This document summarizes toxins produced by plant pathogens and their role in plant pathogenesis. It discusses various classifications of toxins, including pathotoxins, phytotoxins, and vivotoxins. Key points include:
- Pathotoxins play a major role in disease production and cause characteristic disease symptoms. Examples include victorin and T-toxin.
- Phytotoxins' role in disease is suspected but not established, and they cause few disease symptoms. Examples include alternaric acid and piricularin.
- Vivotoxins function in disease production but are not the initial cause; examples include fusaric acid.
The document also covers host-
Toxins produced by plant pathogens play an important role in disease development. There are three classes of toxins: pathotoxins which cause disease symptoms, phytotoxins which may contribute to disease, and vivotoxins which function in disease production but are not the initial cause. Toxins can be host-specific, affecting only the pathogen's host, or non-host specific. Host-specific toxins like T-toxin and victorin are primary determinants of disease in susceptible hosts by disrupting mitochondrial function or stimulating cell death. Non-host specific toxins like tabtoxin and tentoxin do not have host specificity and can affect plant physiology. Toxins cause effects like
This document summarizes toxins produced by plant pathogens. It discusses:
1. Classification of toxins according to source of origin into pathotoxins, phytotoxins, and vivotoxins.
2. Classification based on specificity into host-specific/selective toxins and non-specific/non-selective toxins.
3. Examples of host-specific toxins like T-toxin, HC-toxin, and victorin and their mode of action.
This document discusses toxins produced by plant pathogens. It begins by classifying toxins into three categories: pathotoxins, phytotoxins, and vivotoxins. It then discusses specific toxins in more detail, distinguishing between host-specific toxins and non-host specific toxins. Examples of both types of toxins are provided, along with descriptions of their modes of action and effects on host tissues. Overall, the document reviews the role of toxins in plant disease development and pathogenesis.
This document provides information on plant pathogen toxins. It discusses different types of toxins like exotoxins, endotoxins, pathotoxins, vivotoxins, and phytotoxins. It also describes host-specific toxins produced by fungi like victorin, T-toxin, and HC-toxin and their role in pathogenesis. Non-host specific toxins like tabtoxin and phseolotoxin are also discussed. The effects of toxins on host tissues and some examples of other fungal toxins are summarized.
Role of microbial toxins in plant pathogenesisansarishahid786
This document discusses the role of microbial toxins in plant pathogenesis. It defines toxins as metabolites excreted or released by pathogens that damage host cells. Toxins are classified based on their source and specificity. Host-specific toxins only affect a pathogen's host, while non-host specific toxins can damage unrelated plants. Toxins disrupt cell permeability, metabolic processes, and growth regulation, injuring and killing host cells. They play an important role in disease development and symptom expression.
1. Toxins produced by plant pathogens play important roles in pathogenesis and can be classified as pathotoxins, vivotoxins, or phytotoxins depending on their role.
2. Pathotoxins, like tab-toxin and HMT toxin, play a causal role in disease and reproduce disease symptoms when applied to susceptible hosts.
3. Vivotoxins, like fusaric acid and pyricularin, partially contribute to disease symptoms and can be purified from infected hosts.
4. Many pathogens produce host-selective toxins that only affect their specific host, while others make non-host selective toxins that impact multiple unrelated plant species.
Pathotoxins and plant diseases are discussed. Toxins are low molecular weight compounds produced by plant pathogenic fungi and bacteria that disturb host cell metabolism and cause disease. Notable pathotoxins discussed include victorin from Cochliobolus victoriae which causes oat disease, T-toxin from Bipolaris maydis race T which is host-specific to corn with T-cytoplasm, and HC-toxin from Cochliobolus carbonum race 1 which is also host-specific and causes disease in corn. Alternaria alternata also produces several host-specific toxins on various crops like apple, strawberry, and Japanese pear.
Phytoalexins are toxic compounds produced by plants in response to infection by pathogens or exposure to stresses. They help confer resistance against infecting parasites. The document discusses that phytoalexins are induced after infection and inhibit fungal growth. It provides examples of specific phytoalexins produced by different plants like pisatin in peas and gossypol in cotton in response to various fungi. The document also explains the role of phytoalexins in plant defense and resistance.
Toxins produced by plant pathogens play an important role in disease development. There are three classes of toxins: pathotoxins which cause disease symptoms, phytotoxins which may contribute to disease, and vivotoxins which function in disease production but are not the initial cause. Toxins can be host-specific, affecting only the pathogen's host, or non-host specific. Host-specific toxins like T-toxin and victorin are primary determinants of disease in susceptible hosts by disrupting mitochondrial function or stimulating cell death. Non-host specific toxins like tabtoxin and tentoxin do not have host specificity and can affect plant physiology. Toxins cause effects like
This document summarizes toxins produced by plant pathogens. It discusses:
1. Classification of toxins according to source of origin into pathotoxins, phytotoxins, and vivotoxins.
2. Classification based on specificity into host-specific/selective toxins and non-specific/non-selective toxins.
3. Examples of host-specific toxins like T-toxin, HC-toxin, and victorin and their mode of action.
This document discusses toxins produced by plant pathogens. It begins by classifying toxins into three categories: pathotoxins, phytotoxins, and vivotoxins. It then discusses specific toxins in more detail, distinguishing between host-specific toxins and non-host specific toxins. Examples of both types of toxins are provided, along with descriptions of their modes of action and effects on host tissues. Overall, the document reviews the role of toxins in plant disease development and pathogenesis.
This document provides information on plant pathogen toxins. It discusses different types of toxins like exotoxins, endotoxins, pathotoxins, vivotoxins, and phytotoxins. It also describes host-specific toxins produced by fungi like victorin, T-toxin, and HC-toxin and their role in pathogenesis. Non-host specific toxins like tabtoxin and phseolotoxin are also discussed. The effects of toxins on host tissues and some examples of other fungal toxins are summarized.
Role of microbial toxins in plant pathogenesisansarishahid786
This document discusses the role of microbial toxins in plant pathogenesis. It defines toxins as metabolites excreted or released by pathogens that damage host cells. Toxins are classified based on their source and specificity. Host-specific toxins only affect a pathogen's host, while non-host specific toxins can damage unrelated plants. Toxins disrupt cell permeability, metabolic processes, and growth regulation, injuring and killing host cells. They play an important role in disease development and symptom expression.
1. Toxins produced by plant pathogens play important roles in pathogenesis and can be classified as pathotoxins, vivotoxins, or phytotoxins depending on their role.
2. Pathotoxins, like tab-toxin and HMT toxin, play a causal role in disease and reproduce disease symptoms when applied to susceptible hosts.
3. Vivotoxins, like fusaric acid and pyricularin, partially contribute to disease symptoms and can be purified from infected hosts.
4. Many pathogens produce host-selective toxins that only affect their specific host, while others make non-host selective toxins that impact multiple unrelated plant species.
Pathotoxins and plant diseases are discussed. Toxins are low molecular weight compounds produced by plant pathogenic fungi and bacteria that disturb host cell metabolism and cause disease. Notable pathotoxins discussed include victorin from Cochliobolus victoriae which causes oat disease, T-toxin from Bipolaris maydis race T which is host-specific to corn with T-cytoplasm, and HC-toxin from Cochliobolus carbonum race 1 which is also host-specific and causes disease in corn. Alternaria alternata also produces several host-specific toxins on various crops like apple, strawberry, and Japanese pear.
Phytoalexins are toxic compounds produced by plants in response to infection by pathogens or exposure to stresses. They help confer resistance against infecting parasites. The document discusses that phytoalexins are induced after infection and inhibit fungal growth. It provides examples of specific phytoalexins produced by different plants like pisatin in peas and gossypol in cotton in response to various fungi. The document also explains the role of phytoalexins in plant defense and resistance.
1. Many plant pathogens produce toxins that play an important role in disease development and pathogenesis. Toxins can damage host plants and cause symptoms of disease.
2. Examples are given of historic plant disease outbreaks caused by toxin-producing fungi such as the Irish potato famine. Specific toxins like aflatoxin, trichothecenes, and fumonisins are discussed.
3. Plant pathogens employ diverse toxin strategies to weaken hosts including disrupting membranes, inhibiting amino acid and RNA synthesis, and mimicking plant signals. Understanding toxin function provides insights into host-pathogen interactions and ways to develop disease resistance.
Plant - Pathogen Interaction and Disease DevelopmentKK CHANDEL
Plant diseases are the result of infection by any living organisms that adversely affect the growth, development, physiological functioning and productivity of a plant, manifesting outwardly as visible symptoms.
Plant diseases are caused by living organisms that infect plants and cause visible symptoms. Pathogens are the organisms that cause disease, while the plant is the host. Plants interact with many potential pathogens like bacteria, fungi, viruses, and nematodes. Pathogens have adapted ways to invade plants, overcome defenses, and reproduce. They produce substances that affect plant metabolism. Successful infection depends on properties of the pathogen, host, and environment. At a molecular level, pathogens may use enzymes, toxins, and other chemicals to infect plants. The host plant may respond with programmed cell death reactions like the hypersensitive response to limit infection.
The document discusses biological control of plant diseases. It describes ideal characteristics of biocontrol agents including being non-pathogenic and having a broad spectrum of activity. Common biocontrol agents used are fungi, bacteria, and actinomycetes from the genera Trichoderma, Gliocladium, Pseudomonas, and Bacillus. Mechanisms of biocontrol include direct mechanisms like hyperparasitism and antibiosis, as well as indirect mechanisms like competition and inducing systemic resistance in plants.
Biotic stress refers to stress caused by living organisms that damage plants, such as fungi, bacteria, insects, and weeds. Fungi cause more plant diseases than any other factor, with over 8,000 fungal species known to cause plant diseases. Plants have various defense mechanisms against biotic stress, including physical defenses like cell walls and waxy cuticles, and chemical defenses like terpenoids, phenolics, and nitrogen compounds that are toxic to pathogens and herbivores. Biotic stress can significantly impact plants and cause pre- and post-harvest losses if not properly managed.
This document provides an overview of plant disease concepts and classification. It defines diseases as any abnormal condition that alters a plant's appearance or function. Diseases result from an interaction between a susceptible host, a virulent pathogen, and a favorable environment over time. Symptoms are the visible effects on the host, while signs are structures produced by the pathogen. Diseases are classified based on factors like the type of infection (localized or systemic), means of perpetuation and spread (soil-borne, seed-borne, air-borne), geographic occurrence (endemic, epidemic, sporadic, pandemic), inoculum multiplication (simple or compound interest), causal agent (biotic like fungi, protists, nematodes or abiotic environmental
Role of toxins in Plant pathogenesis and the methods of detection of MycotoxinsSabariGirishP1
Plant pathogens secrete various toxins which causes disease to the plant host by infecting the metabolic process of the host. The toxins secreted may be Host specific or non host specific.
This document provides an introduction to plant pathology. It discusses why plant pathology is important, as plants sustain life but are vulnerable to microorganisms. A healthy plant performs normal functions like growth, nutrient uptake, photosynthesis and reproduction. A diseased plant fails at one or more of these functions. The science of plant pathology has four main objectives: to study disease causes and development, plant-pathogen interactions, and control methods. Key terms are defined, such as pathogen, infection, and symptom. Several examples of serious historical diseases causing famines are described. The major types of phytopathogenic organisms that cause plant diseases are identified as fungi, bacteria, viruses, viroids and others.
Bacterial toxins can be divided into exotoxins and endotoxins. Exotoxins are toxic proteins released from bacterial cells and include cytolytic toxins, AB toxins, and superantigens. Cytolytic toxins damage cell membranes, AB toxins consist of subunits that damage cells, and superantigens trigger cytokine storms. Endotoxins are lipopolysaccharides in Gram-negative bacterial membranes that are released upon cell lysis and cause fever, shock, and organ failure by activating the host immune response. Bacterial toxins contribute to pathogenesis by directly damaging host cells or disabling the immune system.
This document discusses the importance of biological control over chemical control for managing plant diseases. It notes that plant pathogens can infect most crop types and reduce yields. While chemicals are widely used to control bacteria, fungi and nematodes, there are concerns about pathogen resistance, environmental contamination, and human/animal toxicity. Biological control uses organisms like beneficial bacteria, fungi and insects to naturally reduce pathogens through competition, antibiotics or predation. It has benefits like lower impact on other organisms, compatibility with natural enemies, and no toxic residues. The document concludes that biological products are a more sustainable approach to pest control as chemicals are phased out due to resistance or commercial viability issues.
The document discusses host-pathogen interactions and plant parasitism. It begins by defining key terms like host-pathogen interaction and parasitism. It then describes how pathogens can infect hosts on a molecular and cellular level. It discusses the disease cycle, including inoculation, penetration, infection, and dissemination. It explains different types of pathogen interactions with hosts, including obligate and nonobligate parasites. It also discusses symbiotic relationships between some microbes and plants. In summary, the document provides an overview of host-pathogen interactions, the disease cycle, and different types of parasitic relationships between microbes and plants.
parasitism and disease and its remedials.pptxjntuhcej
This document discusses the host-pathogen interaction and plant parasitism. It begins by defining key terms like host, pathogen, parasite, and symbiosis. It then describes how pathogens can infect hosts on a molecular and cellular level and cause disease. It discusses the disease cycle and how pathogens are introduced to hosts, penetrate their surfaces, establish infections, and colonize tissues. The document outlines the roles of inoculum, adhesion, penetration, and environmental conditions in disease development. It also describes different types of parasites and their interactions with host plants.
Plant pathology is the study of diseases that affect plants. The document outlines key concepts in plant pathology including definitions of plant disease, the disease triangle, classification of diseases, and causes of infectious and non-infectious diseases. It also discusses the objectives and importance of plant pathology, summarizing that plant pathology aims to study the causes and mechanisms of disease, epidemiology, and develop management strategies, in order to reduce losses from diseases and meet global food needs.
Plant Pathology is the study of diseases that affect plants. It involves studying the causes, mechanisms, and control of plant diseases. The document discusses key topics in plant pathology including disease cycles, types of pathogens and inoculum, modes of dissemination, and the relationship between disease cycles and epidemics. It provides definitions and examples of important terminology used in plant pathology.
(1) The document discusses endophytes, which are microorganisms that live within plant tissues without causing harm. (2) It describes the types of endophytes including bacteria, fungi, algae, and oomycetes and provides examples of each. (3) Endophytes interact with their host plants in mutualistic ways such as enhancing resistance to pathogens, producing compounds that inhibit other microbes, and promoting plant growth.
The document discusses plant-pathogen interactions and infection mechanisms. It describes how pathogens have adapted to invade plants, overcome defenses, and colonize tissues. Pathogens secrete substances that impact host metabolism and components. Mechanical forces from pathogens aid penetration of cell walls. The gene-for-gene concept explains genetic interactions between a pathogen and its host. At a molecular level, a resistance gene in the host encodes a receptor recognizing an elicitor from the pathogen, triggering defenses. Modes of infection include mechanical forces and use of enzymes, toxins, and growth regulators by pathogens to degrade tissues and interfere with host functions.
Phytoalexins are antimicrobial compounds produced by plants in response to pathogens like fungi and bacteria. Some key phytoalexins include ipomeamarone from sweet potato, pisatin from pea pods, phaseollin from bean pods, and glyceollin I from soybeans. Phytoalexins are synthesized after the plant recognizes molecules from the pathogen. They function to inhibit pathogen growth through mechanisms like disrupting cell membranes or inhibiting energy production. Their production is part of the plant's defense response and helps contribute to resistance against diseases.
L 1.Introduction to PDM kkungggfdrrfftghhhAkash486765
The document provides an introduction to plant pathology and classification of plant diseases. It discusses the objectives of plant pathology and defines what a plant disease is. It then classifies plant diseases based on type of infection, perpetuation and spread, geographic distribution, multiplication of inoculum, host plants affected, symptoms, plant parts affected, and causal agents. It also discusses the history and important discoveries in plant pathology. Integrated disease management is defined as using complementary techniques to keep disease below an economic threshold and avoid resistance.
This document discusses the tree of life and the three domains of life: Bacteria, Archaea, and Eukarya. It provides details on the domains of Bacteria and Archaea, which are both prokaryotes, and notes some of their differences. The domain Eukarya is then discussed, including the kingdoms of plants, fungi, and animals. Key aspects of fungi and plants are summarized, such as fungi obtaining nutrients outside their bodies, and plants producing food through photosynthesis using chloroplasts in leaves.
FFA Judging Plant pathology study guide.pptDawitGetahun6
This document is a study guide for a plant pathology judging contest that was assembled by Tom McCutcheon and Mike Shamblin from various internet sources for educational purposes. It may be copied and distributed without financial compensation as long as the efforts of the authors are recognized. The study guide contains over 50 slides that provide pictures of plant diseases along with their common name and 3 sentences or less about recommended control methods.
1. Many plant pathogens produce toxins that play an important role in disease development and pathogenesis. Toxins can damage host plants and cause symptoms of disease.
2. Examples are given of historic plant disease outbreaks caused by toxin-producing fungi such as the Irish potato famine. Specific toxins like aflatoxin, trichothecenes, and fumonisins are discussed.
3. Plant pathogens employ diverse toxin strategies to weaken hosts including disrupting membranes, inhibiting amino acid and RNA synthesis, and mimicking plant signals. Understanding toxin function provides insights into host-pathogen interactions and ways to develop disease resistance.
Plant - Pathogen Interaction and Disease DevelopmentKK CHANDEL
Plant diseases are the result of infection by any living organisms that adversely affect the growth, development, physiological functioning and productivity of a plant, manifesting outwardly as visible symptoms.
Plant diseases are caused by living organisms that infect plants and cause visible symptoms. Pathogens are the organisms that cause disease, while the plant is the host. Plants interact with many potential pathogens like bacteria, fungi, viruses, and nematodes. Pathogens have adapted ways to invade plants, overcome defenses, and reproduce. They produce substances that affect plant metabolism. Successful infection depends on properties of the pathogen, host, and environment. At a molecular level, pathogens may use enzymes, toxins, and other chemicals to infect plants. The host plant may respond with programmed cell death reactions like the hypersensitive response to limit infection.
The document discusses biological control of plant diseases. It describes ideal characteristics of biocontrol agents including being non-pathogenic and having a broad spectrum of activity. Common biocontrol agents used are fungi, bacteria, and actinomycetes from the genera Trichoderma, Gliocladium, Pseudomonas, and Bacillus. Mechanisms of biocontrol include direct mechanisms like hyperparasitism and antibiosis, as well as indirect mechanisms like competition and inducing systemic resistance in plants.
Biotic stress refers to stress caused by living organisms that damage plants, such as fungi, bacteria, insects, and weeds. Fungi cause more plant diseases than any other factor, with over 8,000 fungal species known to cause plant diseases. Plants have various defense mechanisms against biotic stress, including physical defenses like cell walls and waxy cuticles, and chemical defenses like terpenoids, phenolics, and nitrogen compounds that are toxic to pathogens and herbivores. Biotic stress can significantly impact plants and cause pre- and post-harvest losses if not properly managed.
This document provides an overview of plant disease concepts and classification. It defines diseases as any abnormal condition that alters a plant's appearance or function. Diseases result from an interaction between a susceptible host, a virulent pathogen, and a favorable environment over time. Symptoms are the visible effects on the host, while signs are structures produced by the pathogen. Diseases are classified based on factors like the type of infection (localized or systemic), means of perpetuation and spread (soil-borne, seed-borne, air-borne), geographic occurrence (endemic, epidemic, sporadic, pandemic), inoculum multiplication (simple or compound interest), causal agent (biotic like fungi, protists, nematodes or abiotic environmental
Role of toxins in Plant pathogenesis and the methods of detection of MycotoxinsSabariGirishP1
Plant pathogens secrete various toxins which causes disease to the plant host by infecting the metabolic process of the host. The toxins secreted may be Host specific or non host specific.
This document provides an introduction to plant pathology. It discusses why plant pathology is important, as plants sustain life but are vulnerable to microorganisms. A healthy plant performs normal functions like growth, nutrient uptake, photosynthesis and reproduction. A diseased plant fails at one or more of these functions. The science of plant pathology has four main objectives: to study disease causes and development, plant-pathogen interactions, and control methods. Key terms are defined, such as pathogen, infection, and symptom. Several examples of serious historical diseases causing famines are described. The major types of phytopathogenic organisms that cause plant diseases are identified as fungi, bacteria, viruses, viroids and others.
Bacterial toxins can be divided into exotoxins and endotoxins. Exotoxins are toxic proteins released from bacterial cells and include cytolytic toxins, AB toxins, and superantigens. Cytolytic toxins damage cell membranes, AB toxins consist of subunits that damage cells, and superantigens trigger cytokine storms. Endotoxins are lipopolysaccharides in Gram-negative bacterial membranes that are released upon cell lysis and cause fever, shock, and organ failure by activating the host immune response. Bacterial toxins contribute to pathogenesis by directly damaging host cells or disabling the immune system.
This document discusses the importance of biological control over chemical control for managing plant diseases. It notes that plant pathogens can infect most crop types and reduce yields. While chemicals are widely used to control bacteria, fungi and nematodes, there are concerns about pathogen resistance, environmental contamination, and human/animal toxicity. Biological control uses organisms like beneficial bacteria, fungi and insects to naturally reduce pathogens through competition, antibiotics or predation. It has benefits like lower impact on other organisms, compatibility with natural enemies, and no toxic residues. The document concludes that biological products are a more sustainable approach to pest control as chemicals are phased out due to resistance or commercial viability issues.
The document discusses host-pathogen interactions and plant parasitism. It begins by defining key terms like host-pathogen interaction and parasitism. It then describes how pathogens can infect hosts on a molecular and cellular level. It discusses the disease cycle, including inoculation, penetration, infection, and dissemination. It explains different types of pathogen interactions with hosts, including obligate and nonobligate parasites. It also discusses symbiotic relationships between some microbes and plants. In summary, the document provides an overview of host-pathogen interactions, the disease cycle, and different types of parasitic relationships between microbes and plants.
parasitism and disease and its remedials.pptxjntuhcej
This document discusses the host-pathogen interaction and plant parasitism. It begins by defining key terms like host, pathogen, parasite, and symbiosis. It then describes how pathogens can infect hosts on a molecular and cellular level and cause disease. It discusses the disease cycle and how pathogens are introduced to hosts, penetrate their surfaces, establish infections, and colonize tissues. The document outlines the roles of inoculum, adhesion, penetration, and environmental conditions in disease development. It also describes different types of parasites and their interactions with host plants.
Plant pathology is the study of diseases that affect plants. The document outlines key concepts in plant pathology including definitions of plant disease, the disease triangle, classification of diseases, and causes of infectious and non-infectious diseases. It also discusses the objectives and importance of plant pathology, summarizing that plant pathology aims to study the causes and mechanisms of disease, epidemiology, and develop management strategies, in order to reduce losses from diseases and meet global food needs.
Plant Pathology is the study of diseases that affect plants. It involves studying the causes, mechanisms, and control of plant diseases. The document discusses key topics in plant pathology including disease cycles, types of pathogens and inoculum, modes of dissemination, and the relationship between disease cycles and epidemics. It provides definitions and examples of important terminology used in plant pathology.
(1) The document discusses endophytes, which are microorganisms that live within plant tissues without causing harm. (2) It describes the types of endophytes including bacteria, fungi, algae, and oomycetes and provides examples of each. (3) Endophytes interact with their host plants in mutualistic ways such as enhancing resistance to pathogens, producing compounds that inhibit other microbes, and promoting plant growth.
The document discusses plant-pathogen interactions and infection mechanisms. It describes how pathogens have adapted to invade plants, overcome defenses, and colonize tissues. Pathogens secrete substances that impact host metabolism and components. Mechanical forces from pathogens aid penetration of cell walls. The gene-for-gene concept explains genetic interactions between a pathogen and its host. At a molecular level, a resistance gene in the host encodes a receptor recognizing an elicitor from the pathogen, triggering defenses. Modes of infection include mechanical forces and use of enzymes, toxins, and growth regulators by pathogens to degrade tissues and interfere with host functions.
Phytoalexins are antimicrobial compounds produced by plants in response to pathogens like fungi and bacteria. Some key phytoalexins include ipomeamarone from sweet potato, pisatin from pea pods, phaseollin from bean pods, and glyceollin I from soybeans. Phytoalexins are synthesized after the plant recognizes molecules from the pathogen. They function to inhibit pathogen growth through mechanisms like disrupting cell membranes or inhibiting energy production. Their production is part of the plant's defense response and helps contribute to resistance against diseases.
L 1.Introduction to PDM kkungggfdrrfftghhhAkash486765
The document provides an introduction to plant pathology and classification of plant diseases. It discusses the objectives of plant pathology and defines what a plant disease is. It then classifies plant diseases based on type of infection, perpetuation and spread, geographic distribution, multiplication of inoculum, host plants affected, symptoms, plant parts affected, and causal agents. It also discusses the history and important discoveries in plant pathology. Integrated disease management is defined as using complementary techniques to keep disease below an economic threshold and avoid resistance.
This document discusses the tree of life and the three domains of life: Bacteria, Archaea, and Eukarya. It provides details on the domains of Bacteria and Archaea, which are both prokaryotes, and notes some of their differences. The domain Eukarya is then discussed, including the kingdoms of plants, fungi, and animals. Key aspects of fungi and plants are summarized, such as fungi obtaining nutrients outside their bodies, and plants producing food through photosynthesis using chloroplasts in leaves.
FFA Judging Plant pathology study guide.pptDawitGetahun6
This document is a study guide for a plant pathology judging contest that was assembled by Tom McCutcheon and Mike Shamblin from various internet sources for educational purposes. It may be copied and distributed without financial compensation as long as the efforts of the authors are recognized. The study guide contains over 50 slides that provide pictures of plant diseases along with their common name and 3 sentences or less about recommended control methods.
Fungi are a diverse group of organisms that are ubiquitous in terrestrial and freshwater environments. They play important ecological roles in recycling organic matter as saprotrophs, symbionts, and parasites. Fungi can be unicellular yeasts or multicellular molds composed of threadlike filaments called hyphae. Hyphae may be septate or coenocytic, and form together into a mat-like structure called a mycelium. Fungi are classified based on their sexual reproduction structures and spores as well as hyphal morphology. The four main classes of medically important fungi are Ascomycetes, Basidiomycetes, Deuteromycetes, and Phy
plant pathology and plant disease 1516297.pptDawitGetahun6
This document provides an overview of plant pathology principles organized into jeopardy game format. It covers topics including Oomycota, Ascomycota, symptoms and signs of disease, disease management, terminology used in plant pathology, and general mycology. For each topic, there are 5 questions ranging from 100 to 500 points about key concepts within that category.
Lecture 3- Bacterial Nutrition and Growth-.pptDawitGetahun6
This document discusses various environmental factors that affect microbial growth, including temperature, pH, osmotic pressure, and oxygen levels. It describes how microorganisms are classified based on their optimal and maximum temperature ranges, as well as their ability to grow under acidic, alkaline, high salt, or anaerobic conditions. The document also covers microbial nutrition requirements, discussing the main macronutrients of carbon, nitrogen, phosphorus, and others needed for growth, and how organisms are categorized based on their carbon and energy sources.
Nutrient cycles occur at both the local ecosystem level through biological processes, and the global level through geological processes and atmospheric circulation. Key nutrients like carbon, oxygen, hydrogen, nitrogen, and phosphorus cycle through biotic and abiotic compartments of ecosystems, including organisms, soils, atmosphere, and oceans. At the global scale, the hydrosphere and atmosphere drive the water cycle, while carbon and nitrogen cycle through oceans, soils, atmosphere, and biosphere. Human activities are altering global nutrient cycles, such as through the addition of nitrogen to ecosystems from fossil fuel combustion.
Rhizobacteria are root-colonizing bacteria that form symbiotic relationships with plants. They are often referred to as plant growth-promoting rhizobacteria (PGPR) as they enhance plant growth through mechanisms such as nitrogen fixation, phosphate solubilization, and inducing systemic resistance against pathogens. Rhizobacteria have various applications as bioinoculants, biofertilizers, and biocontrol agents to promote plant growth and reduce the need for chemical fertilizers and pesticides. Future prospects include genetically engineering PGPR to overexpress beneficial traits and improve their biocontrol efficacy through synergistic effects.
The document discusses three key biogeochemical cycles - carbon, nitrogen, and phosphorus. It provides details on each cycle, including:
1) The carbon cycle involves the movement of carbon between the atmosphere, organisms, and fossils fuels. Plants and animals exchange carbon via photosynthesis and respiration. Human emissions impact the cycle.
2) Nitrogen circulates between the air, soil, plants and animals through nitrogen fixation, plant/animal uptake, and denitrification. It is essential for proteins but scarce without bacterial conversion.
3) Phosphorus cycles slowly between rocks, soil and organisms and is important for energy transfer and genetic material. Excess fertilizer runoff impacts nitrogen and phosphorus cycles in waterways
The document summarizes microbiology techniques for culturing and observing microbes. It describes the five steps for culturing as inoculation, isolation, incubation, inspection, and identification. Inoculation introduces microbes to growth media. Isolation produces pure cultures on agar plates. Incubation allows growth under optimal conditions. Inspection involves observing colony morphology and staining for microscopy. Identification correlates observed characteristics to identify the microbe. It also explains light and electron microscopy, describing their components, resolutions, and sample preparation techniques like staining.
metabolsim of microorganism 1664107090.pptDawitGetahun6
Microbial metabolism involves the breakdown and synthesis of complex molecules. There are two main types of metabolism: catabolism which breaks down molecules and releases energy, and anabolism which uses energy to build complex molecules. Microbes metabolize carbohydrates, lipids, and proteins through various pathways. During aerobic respiration, glucose is completely oxidized using oxygen as the final electron acceptor to generate ATP. Fermentation pathways produce ATP without oxygen by using organic molecules as electron acceptors. The study of microbial metabolism is important for food production and preservation.
agri microbiology for Micro Hort PPT.pptxDawitGetahun6
1. The document discusses various microscopy techniques used to study microorganisms, including bright-field, dark-field, phase-contrast, and fluorescent microscopy. It also covers electron microscopy.
2. Microorganisms can be classified as prokaryotes or eukaryotes. Prokaryotes include bacteria and archaea and lack a nucleus, while eukaryotes such as protists, fungi, plants and animals have membrane-bound organelles including a nucleus.
3. The key differences between prokaryotic and eukaryotic cells are that eukaryotic cells have a nucleus enclosed in a membrane, linear DNA, histones, chromosomes, and membrane-bound organelles, while
method of studing microbial 13114527.pptDawitGetahun6
The document discusses various types of culture media used for growing microorganisms in the laboratory, including chemically defined media which has an exact known composition, complex media made from extracts of yeasts and meats which provide nutrients like carbon, nitrogen and vitamins, and solid media which uses agar as a solidifying agent to allow bacterial growth on surfaces like test tubes and Petri dishes. The different media types are selected based on the specific microorganism being cultured and whether a solid or liquid growth surface is needed.
growth of microorganism chp 7-8 ppt.pptDawitGetahun6
1. Bacterial growth occurs through binary fission and can happen rapidly depending on environmental conditions like temperature and nutrient levels. The number of bacterial cells increases exponentially.
2. Microbial growth is affected by environmental factors like temperature and pH as well as chemical factors including proper concentrations of carbon, hydrogen, oxygen, nitrogen, phosphorus, and trace elements.
3. A bacterial growth curve consists of four phases - lag, log, stationary, and death - and is used to understand microbial growth under different conditions and the effect of various chemicals and temperatures. Growth is typically measured through turbidity using a spectrophotometer.
This document outlines the historical development of microbiology from the 17th century to present day. It discusses the key early discoveries including van Leeuwenhoek's discovery of microorganisms under the microscope in the 1670s. Later sections cover the development of vaccines and antimicrobial therapies like antibiotics. It also addresses the role of microbes in industry and emerging diseases in the post-antibiotic era.
in the soil micriobial bioremediation2.pptDawitGetahun6
This document defines and describes various methods of bioremediation. It discusses in situ bioremediation techniques like bioventing, biodegradation and bioaugmentation that treat contamination on-site. Ex situ techniques like land farming and composting remove contamination for off-site treatment. Phytoremediation uses plants to extract, degrade, stabilize or filter contaminants. The effectiveness of bioremediation depends on microorganisms, environmental factors and the contaminant type.
Soil is a complex medium that provides nutrients and support for plant growth. It is composed of minerals, air, water, and organic matter. Soil forms over long periods through weathering and the activity of organisms. Key factors that influence soil formation are parent material, climate, organisms, topography, and time. Soil provides nutrients, water, and anchorage for plants through complex nutrient cycles and soil profiles that vary in texture, structure, pH, and organic content. Proper soil management through practices like tillage, no-till, and conservation methods helps maintain healthy soil that supports plant growth.
Lecture 2- on Cell Structures.ppt biologyDawitGetahun6
Fungi are eukaryotic, spore-bearing organisms that produce extracellular enzymes and absorb nutrients. Their basic cellular unit is the hypha, which can be septate or coenocytic. Fungi have typical eukaryotic organelles like mitochondria and nuclei, as well as fungal-specific structures involved in cell wall growth. They reproduce both sexually through spores formed via meiosis and asexually via mitotic spores. Fungal life cycles can be predominantly haploid, dikaryotic, or diploid depending on when karyogamy and meiosis occur. Important model fungi like Neurospora crassa were influential in developing concepts in genetics.
The document provides an overview of plant pathology and the history of several important plant diseases. It discusses causal agents of disease including fungi, bacteria, nematodes and viruses. Several significant diseases that have impacted agriculture throughout history are summarized, including late blight of potato in Ireland which caused the Irish Potato Famine, chestnut blight which wiped out the American chestnut, Dutch elm disease which devastated street trees, and sudden oak death first discovered in California in the 1990s.
This document summarizes key aspects of the kingdom Fungi. It describes the characteristics of fungi, including their heterotrophic nutrition and modes of growth. It discusses fungal life cycles and roles as decomposers, symbionts through mycorrhizae and lichens, and parasites. The evolution and classification of fungi is covered, focusing on the four main phyla: Chytridiomycota, Zygomycota, Ascomycota, and Basidiomycota. Representative fungi from each phylum are described along with their reproductive structures and life cycles.
what is plant pathology and plant disease .pptDawitGetahun6
Plant pathology is the study of plant diseases caused by pathogens such as fungi, bacteria, viruses and nematodes. Throughout history, devastating plant diseases like the Irish Potato Famine caused by late blight have resulted in millions of deaths. Today, plant diseases cause $8 billion in annual losses to U.S. crops. Plant pathologists work to understand and manage diseases through research and developing control methods to protect food and plant health.
Leveraging Generative AI to Drive Nonprofit InnovationTechSoup
In this webinar, participants learned how to utilize Generative AI to streamline operations and elevate member engagement. Amazon Web Service experts provided a customer specific use cases and dived into low/no-code tools that are quick and easy to deploy through Amazon Web Service (AWS.)
How to Fix the Import Error in the Odoo 17Celine George
An import error occurs when a program fails to import a module or library, disrupting its execution. In languages like Python, this issue arises when the specified module cannot be found or accessed, hindering the program's functionality. Resolving import errors is crucial for maintaining smooth software operation and uninterrupted development processes.
ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
Denis is a dynamic and results-driven Chief Information Officer (CIO) with a distinguished career spanning information systems analysis and technical project management. With a proven track record of spearheading the design and delivery of cutting-edge Information Management solutions, he has consistently elevated business operations, streamlined reporting functions, and maximized process efficiency.
Certified as an ISO/IEC 27001: Information Security Management Systems (ISMS) Lead Implementer, Data Protection Officer, and Cyber Risks Analyst, Denis brings a heightened focus on data security, privacy, and cyber resilience to every endeavor.
His expertise extends across a diverse spectrum of reporting, database, and web development applications, underpinned by an exceptional grasp of data storage and virtualization technologies. His proficiency in application testing, database administration, and data cleansing ensures seamless execution of complex projects.
What sets Denis apart is his comprehensive understanding of Business and Systems Analysis technologies, honed through involvement in all phases of the Software Development Lifecycle (SDLC). From meticulous requirements gathering to precise analysis, innovative design, rigorous development, thorough testing, and successful implementation, he has consistently delivered exceptional results.
Throughout his career, he has taken on multifaceted roles, from leading technical project management teams to owning solutions that drive operational excellence. His conscientious and proactive approach is unwavering, whether he is working independently or collaboratively within a team. His ability to connect with colleagues on a personal level underscores his commitment to fostering a harmonious and productive workplace environment.
Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
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How to Manage Your Lost Opportunities in Odoo 17 CRMCeline George
Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
Reimagining Your Library Space: How to Increase the Vibes in Your Library No ...Diana Rendina
Librarians are leading the way in creating future-ready citizens – now we need to update our spaces to match. In this session, attendees will get inspiration for transforming their library spaces. You’ll learn how to survey students and patrons, create a focus group, and use design thinking to brainstorm ideas for your space. We’ll discuss budget friendly ways to change your space as well as how to find funding. No matter where you’re at, you’ll find ideas for reimagining your space in this session.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
environment for investigating the changes in vegetation cover dynamics. Our study utilizes
advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
analyze the transformations that have taken place over the course of a decade.
The complex relationship between human activities and the environment has been the focus
of extensive research and worry. As the global community grapples with swift urbanization,
population expansion, and economic progress, the effects on natural ecosystems are becoming
more evident. A crucial element of this impact is the alteration of vegetation cover, which plays a
significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
Chapter wise All Notes of First year Basic Civil Engineering.pptxDenish Jangid
Chapter wise All Notes of First year Basic Civil Engineering
Syllabus
Chapter-1
Introduction to objective, scope and outcome the subject
Chapter 2
Introduction: Scope and Specialization of Civil Engineering, Role of civil Engineer in Society, Impact of infrastructural development on economy of country.
Chapter 3
Surveying: Object Principles & Types of Surveying; Site Plans, Plans & Maps; Scales & Unit of different Measurements.
Linear Measurements: Instruments used. Linear Measurement by Tape, Ranging out Survey Lines and overcoming Obstructions; Measurements on sloping ground; Tape corrections, conventional symbols. Angular Measurements: Instruments used; Introduction to Compass Surveying, Bearings and Longitude & Latitude of a Line, Introduction to total station.
Levelling: Instrument used Object of levelling, Methods of levelling in brief, and Contour maps.
Chapter 4
Buildings: Selection of site for Buildings, Layout of Building Plan, Types of buildings, Plinth area, carpet area, floor space index, Introduction to building byelaws, concept of sun light & ventilation. Components of Buildings & their functions, Basic concept of R.C.C., Introduction to types of foundation
Chapter 5
Transportation: Introduction to Transportation Engineering; Traffic and Road Safety: Types and Characteristics of Various Modes of Transportation; Various Road Traffic Signs, Causes of Accidents and Road Safety Measures.
Chapter 6
Environmental Engineering: Environmental Pollution, Environmental Acts and Regulations, Functional Concepts of Ecology, Basics of Species, Biodiversity, Ecosystem, Hydrological Cycle; Chemical Cycles: Carbon, Nitrogen & Phosphorus; Energy Flow in Ecosystems.
Water Pollution: Water Quality standards, Introduction to Treatment & Disposal of Waste Water. Reuse and Saving of Water, Rain Water Harvesting. Solid Waste Management: Classification of Solid Waste, Collection, Transportation and Disposal of Solid. Recycling of Solid Waste: Energy Recovery, Sanitary Landfill, On-Site Sanitation. Air & Noise Pollution: Primary and Secondary air pollutants, Harmful effects of Air Pollution, Control of Air Pollution. . Noise Pollution Harmful Effects of noise pollution, control of noise pollution, Global warming & Climate Change, Ozone depletion, Greenhouse effect
Text Books:
1. Palancharmy, Basic Civil Engineering, McGraw Hill publishers.
2. Satheesh Gopi, Basic Civil Engineering, Pearson Publishers.
3. Ketki Rangwala Dalal, Essentials of Civil Engineering, Charotar Publishing House.
4. BCP, Surveying volume 1
This document provides an overview of wound healing, its functions, stages, mechanisms, factors affecting it, and complications.
A wound is a break in the integrity of the skin or tissues, which may be associated with disruption of the structure and function.
Healing is the body’s response to injury in an attempt to restore normal structure and functions.
Healing can occur in two ways: Regeneration and Repair
There are 4 phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. This document also describes the mechanism of wound healing. Factors that affect healing include infection, uncontrolled diabetes, poor nutrition, age, anemia, the presence of foreign bodies, etc.
Complications of wound healing like infection, hyperpigmentation of scar, contractures, and keloid formation.
2. .
Doctoral Seminar II
O
n
Role of Toxins in Plant Pathogenesis
Major Advisor
Dr.Dayara
m
Univ.Prof.
Deptt. Of
Plant
Pathology
Speaker
Mukesh
Kumar Ph.D
Scholar
Department of Plant Pathology
Dr. Rajendra Prasad Central Agricultural University Pusa,
Samastipur, 848185 (Bihar) India
6. Classification of toxins
..
According to the source of origin, toxins are divided
into 3 broad classes namely.
1. Pathotoxins
2. Phytotoxins
3. Vivotoxins
(Wheeler and Luke, 1963)
7. A. Pathotoxins
.
1. These are the toxins which play a major role in
disease production and produce all or most of the
symptoms characteristic of the disease in
susceptible plants.
2. Most of these toxins are produced by pathogens
during pathogenesis.
Ex: Victorin: Cochliobolus victoriae
(Helminthosporium victoriae), the causal agent of
Victoria blight of oats. This is a host specific toxin.
8. B. Phytotoxins
1.These are the substances produced in the host plant due to host-
pathogen interactions for which a causal role in disease is merely
suspected rather than established.
2.These are the products of parasites which induce few or none of
the symptoms caused by the living pathogen.
3.They are non specific and there is no relationship between toxin
production and pathogenicity of disease causing agent.
Ex: Alternaric acid – Alternaria solani.
Piricularin- Pyricularia oryzae.
(Wheeler and Luke, 1963)
9. C. Vivotoxins
1.These are the substances produced in the infected
host by the pathogen and / or its host which functions
in the production of the disease, but is not itself the
initial inciting agent of the disease.
Ex:-Fusaric acid – Wilt causing Fusarium sp.
(Dimond and Waggoner, 1953)
10. Classification based on specificity of toxins
1.Host specific / Host selective toxins:- These are the metabolic
products of the pathogens which are selectively toxic only to the
susceptible host of the pathogen.
Ex:- Victorin, T-toxin, Phyto-alternarin,Amylovorin.
2.Non-specific/Non-selective toxin:- These are the metabolic
products of the pathogen, but do not have host specificity and affect
the protoplasm of many unrelated plant species that are normally
not infected by the pathogen.
Ex: Ten-toxin, Tab-toxin, Fusaric acid, Piricularin,
Lycomarasmin and Alternaric acid
(Scheffer, 1983)
11. Differentiate host – specific and non-host specific toxins
Hostspecific Non-host specific
Host specific.
toxic
host
1. Selectively
susceptible
pathogen.
2. Primary determinants of
disease.
3. Produce all the essential
symptoms of the disease.
Ex: Victorin, T-toxin
Non-host specific.
only to 1. No host specificity and can
of the also affect the physiology of
those plant that are normally
not infected by the pathogen.
2. Secondary determinants of
disease.
3. Produce few or none of the
symptoms of the disease.
Ex: Tentoxin, Tabtoxin
12. A. Host specific:-
T-toxin: Helminthosporium maydis
HC-toxin: Helminthosporium carbonum.
HS- toxin: Helminthosporium sacchari.
Phytoalternarin: Alternaria kikuchiana
PC- toxin: Periconia circinata
B. Non-host specific:-
Tentoxin: Alternaria tenuis.
Tabtoxin or wild fire toxin: Pseudomonas tabaci.
Phaseolotoxin: Pseudomonas syringae pv. Phaseolicola.
13. Effect of toxins on host tissues
. (Singh, 2001)
1. Changes in cell wall permeability:
Toxins kill plant cells by altering the permeability of
plasma membrane, thus permitting loss of water and
electrolytes and also unrestricted entry of substances
including toxins. Cellular transport system, especially,
H+ / K+ exchange at the cell membrane is affected.
14. Increase in respiration due to disturbed salt balance.
Malfunctioning of enzyme system
(Singh, 2001)
2.Disruption of normal metabolic processes:-
15. Interfere with the growth regulatory system of the host plant.
Some toxins inhibit root growth.
Ex:-Fusarium moniliforme produces a thermostable toxin
even in soil around the root which causes browning of the root
and their restricted development.
. (Singh,
2001)
3. Other mechanisms:-
16. The selective (Host-specific) Toxins
T-toxin or Helminthosporium maydis race T-toxin (HMT-toxin)
Is produced by the fungus Helminthosporium maydis ( Cochiobolus
heterostrophus). The pathogen cause leaf blight of maize.
T-toxin is the disrupting the function of the mitochondria of Tcms
maize.
T-toxin bind to inner mitochondrial membrane protein (URF-13),
the product of the T-URF 13, gene to create a pore on the
membrane, cause leakage of small molecules, and subsequently
inhibit ATPsynthesis, resulting in cell death.
17. The Effect of T-toxin From Cochliobolus heterostrophus on T-cms
maize
T-toxin bind to inner mitochondrial membrane protein (URF-13), the
product of the T-URF 13, gene to create a pore on the membrane, cause
leakage of small molecules, and subsequently inhibit ATP synthesis,
resulting in cell death.
18. Is one of the most impotent and selective Pathotoxins. it is the first-
well documented and widely recognised host-specific toxin.
This toxin is produced by Cochliobolus victoriae, the fungus that
causes victoria blight of oat.
The disease is characterised by necrosis of the root and stem base
and blighting of leaves.
It is highly mobile in the plant.
Victorin or HV-toxin:
19. The current model of victorin-induced cellular responses.
(Tada et al., 2005)
The current model of victorin-induced cellular responses. Victorin-sensitive cells. (A)
Victorin may interact with an extracellular mediator( s) in Vb/Pc-2 oats and stimulates ion
fluxes across the plasma membrane, followed by the activation of defense responses and
rapid cell death. After cell death, victorin may permeate cells and is distributed in the
mitochondria, inducing a senescence-like response. (B) Victorin-insensitive cells. Victorin
neither induces cell death nor enters the resistant cells.
20. The fungus causes leaf spot of maize. The fungus species has tow
races, 1 and 2. only race 1 produces the HC-toxin.
Race 1 is also weak pathogenic on most lines but is highly virulent
on maize that is homozygous recessive at the Mendelian loci Hm1
and Hm2.
HC- toxin or Helminthosporium carbonum toxin
21. Infection of maize by Cochliobolus carbonum race 1 (HC-toxin-producing). The
plants in the foreground are genotype hm1/hm1 hm2/hm2 (susceptible). A few
plants were inoculated by spraying conidia and the other plants became
infected by natural spread. The plants in the background are genotype Hm1/-
(resistant).
(Baidyaroy et al., 2001)
22. The eyespot disease caused by Helminthosporium sacchari is
especially severe in seedling of certain sugarcane cultivars.
The host specific toxin produced by the fungus induces reddish
brown strip when injected into susceptible leaves.
The toxin brings about changes in chloroplast and cell wall
permeability .
HS- toxin or Helminthosporium sacchari
23.
24. Milo disease or periconia blight caused by periconia circinata
attacks only milo type of grain sorghum.
The pathogen is soil-borne and invade the root and lower
internodes of the plant.
The toxin causes rapid loss of potassium ions and other materials
through leakage of the plasma membrane of susceptible but not
resistance tissues.
PC-toxin or periconia toxin:
25. Host-specific Toxins in Relation to Pathogenesis and Disease
Resistance R.P. SCHEFFER
Effect of Periconia circinata toxin on susceptible and resistant
sorghum seedlings. Equal amounts of toxin were added to the
nutrient solution of the susceptible (center) and resistant (right)
seedlings three days before this picture was taken. The untreated
control is on the left
26. This host specific toxin is produced by Alternaria kikuchiana,
the fungus causing black spot of japanese pear.
Three Phytoalternarin A, B and C have been obtained from
culture filtrates of the fungus.
There is direct damage to the plasma membrane leading to a rapid
loss of electrolytes.
AK-toxin Phytoalternarin:
27.
28. Pseudomonas syringae pv. tabaci the causal
Tabtoxin or Wildfire toxin:- Tabtoxin is produced by
bacterium of
tobacco wildfire disease.
In tobacco wildfire disease the necrotic lesion on the leaves are
surrounded by a yellow halo.
Most of the toxins produced by plant pathogens are pleiotropic
that is, they have more than one effect on the host cell, but most
bacterial toxin, include tabtoxin, are monotropic, having single
effect
Non-specific/Non-selective toxin:
29. Disease development on transgenic tobacco leaves inoculated with P. syringae pv.
tabaci. Tobacco plants were inoculated at two points per leaf with P. syringae pv. Tabaci
(109bacteria/ml) by the multiple needle method and kept for 6 days in a humid box to
develop the disease. Control tobacco (left) shows the chlorotic symptoms of pathogen
attack, whereas the transgenic tobacco TAB7 (right) exhibits no symptoms at the
inoculation sites of P.syringae pv. tabaci.
30. Phaseolotoxin: Pseudomonas syringae pv. Phaseolicola, causes halo
blight of bean and some other legumes.
Thechlorotic halos are accompanied by ornithine accumulation in
the tissues.
Both race 1 and race 2 of P. phaseolicola can produce
phaseolotoxin, but they differ in host range, suggesting that the
toxin is not involved in host specificity.
Phaseolotoxin
31.
32. Is Produced by Alternaria alternata. causes leaf spots.
That bind to inactivate the protein.
Also inhibits phosphorylation of ADPtoATP
.
Leading to disruption of chlorophyllsynthesis
Tentoxin:
33. Toxicity of AK-toxin produced by the Japanese pear pathotype of Alternaria
alternata. The culture filtrate of the Japanese pear pathotype was dropped on
slightly wounded points of left-half leaves. Right-half leaves were spray
inoculated with a conidial suspension. Leaves were incubated for 24 h.
34. Effect of toxin from Alternaria citri on a leaf of the host plant. Top leaf: 2 days after
a 50 µg drop containing 0.05 µg of toxin was placed on each side of the midrib,
near the leaf center. Control leaf is shown below. (Kohmoto, 1999).
35. Cercosporin
Produced by Cercospora sp.
Causes leaf spot disease of groundnut
This toxin is activated by light and become toxic to plants by
generating activated species if oxygen (single O2); the activated O2
destroy the host membrane and provide nutrients topathogen,
36. Cercosporin production and mode of action. Cercosporin is produced by the fungus in response to
environmental cues, primarily light. Once produced and excreted by the fungus, the cercosporin
molecule is activated by light to generate activated oxygen species. The activated oxygen species, in
turn, cause peroxidation of the plant host membrane lipids, leading to membrane damage and cell
death. Membrane damage allows for leakage of nutrients from the host leaf cells into the leaf
intercellular spaces, and is hypothesized to be the mechanism that provides these intercellular
pathogens with the nutrients required for growth and sporulation in host tissues. (Ehrenshaft et al.,
2000)
38. Ergot alkaloid
The most prominent member of this group is Claviceps
purpurea.
This fungus grows on rye and related plants and produces
alkaloids.
Cause ergotisms in humans and other mammals who consume
grains contaminated with its fruiting structure called ergot
Sclerotium.
39.
40. Aflatoxin
Aspergillus flavus, Aspergillus nomius and Aspergillus
parasiticus.
There are four kinds of Aflatoxins such as Aflatoxin B1, B2, G1
and G2, in which Aflatoxin B1 (AFB1) is highly toxic and
carcinogenic (Leontopoulos et al., 2003) .
Aflatoxins are known to be carcinogenic agents that are
serious hazards to human and animal health (Sidhu et al.,
2009).
In addition, Aflatoxin also has an impact on agricultural
economy through the loss of crop production (Wu, 2004).
43. Conclusions
Plant toxins confer a competitive advantage to the plant, and
especially protect it from insect attack or plant pathogens.
Poisoning of livestock is coincidental to this function.
Since plant toxins seem specifically targeted on insects, either by
concentration in a particular plant part or by production at
concentrations sufficient to intoxicate the insect, livestock
poisonings may be avoidable.
Careful management plants should be developed so that
consumption of the toxic plant parts are avoided.