Since the beginning of the 90s lots of cationic plant, cysteine-rich antimicrobial peptides (AMP) have been studied. However, Broekaert et al. (1995) only coined the term “plant defensin,” after comparison of a new class of plant antifungal peptides with known insect defensins. From there, many plant defensins have been reported and studies on this class of peptides encompass its activity toward microorganisms and molecular features of the mechanism of action against bacteria and fungi. Plant defensins also have been tested as biotechnological tools to improve crop production through fungi resistance generation in organisms genetically modified (OGM). Its low effective concentration towards fungi, ranging from 0.1 to 10 μM and its safety to mammals and birds makes them a better choice, in place of chemicals, to control fungi infection on crop fields. Herein, is a review of the history of plant defensins since their discovery at the beginning of 90s, following the advances on its structure conformation and mechanism of action towards microorganisms is reported. This review also points out some important topics, including: (i) the most studied plant defensins and their fungal targets; (ii) the molecular features of plant defensins and their relation with antifungal activity; (iii) the possibility of using plant defensin(s) genes to generate fungi resistant GM crops and biofungicides; and (iv) a brief discussion about the absence of products in the market containing plant antifungal defensins.
Role of antimicrobial peptides in plant disease management N.H. Shankar Reddy
It is one of the advanced topics in plant disease management, detailed information about antimicrobial peptides and their role in plant disease management is furnished clearly.
plant pathogen interaction
different types of pathogens
gene for gene hypothesis
direct receptor model
Elicitor receptor model
suppersor repressor model
gaurd hypothesis
Role of antimicrobial peptides in plant disease management N.H. Shankar Reddy
It is one of the advanced topics in plant disease management, detailed information about antimicrobial peptides and their role in plant disease management is furnished clearly.
plant pathogen interaction
different types of pathogens
gene for gene hypothesis
direct receptor model
Elicitor receptor model
suppersor repressor model
gaurd hypothesis
Systemic acquired resistance (SAR): A novel strategy for plant protection.mohd younus wani
Exclusive reliance on pesticides, fungicides and herbicides resulted in pesticide and herbicide, resistance, pest resurgence, residues, environmental pollution. Plants have developed various resistance mechanisms to help them adapt to pathogen and insect attack (Jones and Dangl, 2006). Systemic acquired resistance (SAR) is a form of induced resistance that is activated throughout a plant after being exposed to elicitors from virulent, avirulent, or nonpathogenic microbes, or artificial chemical stimuli such as chitosan or salicylic acid (SA) (Gozzo and Faoro, 2013).It is a mechanism of induced defense that confers long-lasting protection against a broad spectrum of microorganisms. SAR requires the signal molecule salicylic acid (SA) and is associated with accumulation of pathogenesis-related proteins, which contribute resistance to the plants.
They can be used as fungicide alternative without any threat of developing resistance and being safe and ecofriendly (Najar et al, 2010). The elicitor, β-Amino butyric acid induces greater systemic resistance to mulberry in addition to enhancement in biochemical parameters and NPK contents of mulberry leaves (Mazal, 2014).Therefore, in order to control the diseases of mulberry without adverse effect on environment, humans and silkworms health attention needs to be given to promote SAR chemicals. A model needs to be framed to promote the use of these chemicals in order to make sericulture more profitable. This is an ecofriendly approach of disease and pest management. The chitinase genes of mulberry induced by insect wounding and fungal infection, suggesting that these chitinases help the mulberry plant to cope with the challenges from insects and fungi (Wang et al., 2015). Jasmonic acid (JA) is an important plant defense signal mediating resistance to herbivores.
Presently disease control is largely depends on the use of fungicides, bactericides and insecticides. The hazardous nature of these chemicals on the environment, human health and silkworm strongly necessitates the search for new, harmless means of disease control.Induced resistance like SAR can diminish the use of toxic chemicals for disease control and thus could be proposed as an alternative, non-biocidal, ecologically-friendly approach for plant protection and hence for sustainable Sericulture. Induced resistance is increased expression of Natural defense mechanisms against different pathogens provoked by external factors of various types. Systemic acquired resistance (SAR) is a "whole-plant" resistance response and can be distinguished from other disease resistant responses by both the spectrum of pathogen protection and the associated changes with gene expression.
Prime-ome: "A molecular approach towards defense priming"Dhanya AJ
Prime-ome is the entire set of messenger RNA (mRNA) molécules or transcripts, proteins and metabolites produced or modified by an organism or system during the different stages of priming in plants and prime-omics is the study of prime-ome.
Molecular basis of plant resistance and defense responses to pathogensSenthil Natesan
In response to pathogen attack, plants have evolved sophisticated defense mechanisms to delay or arrest pathogen growth.Unlike animals, plants lack a circulating immune system recognizing microbial pathogens. Plant cells are more autonomous in their defense mechanisms and rely on the innate immune capacity of each cell and systemic signals that disseminate from infection sites (Jones and Dangl, 2006). Plant innate immunity consists of preformed physical and chemical barriers (such as leaf hairs, rigid cell walls, pre-existing antimicrobial compounds) and induced defenses. Should an invading microbe successfully breach the pre-formed barriers, it may be recognized by the plant, resulting in the activation of cellular defense responses that stop or restrict further development of the invader.
Host-pathogen Interactions, Molecular Basis and Host Defense: Pathogen Detect...QIAGEN
Host–pathogen interactions are strikingly complex during infection. This slidedeck provides an overview of the molecular basis of these intricate interactions: the impact of microbiota on innate and adaptive immunity, metabolism, and insulin resistance and host defense mechanisms. Various research tools will be introduced to simplify and streamline each step of studying the host response, enabling detection of pathogens, analysis of gene expression and regulation, epigenetic modification, genotyping and signal transduction pathway activation.
— The diseases caused by bipartite Begomoviruses have emerged as overwhelming problem in various cropping systems of Pakistan. The study was conducted to evaluate the potential of induced resistance in mungbean to Mungbean yellow mosaic virus (MYMV) disease. In this work, resistance to MYMV infection was induced in mungbean plants by activating the Salicylic acid (SA) pathway using SA and Benzothiadiazole (BTH) as treatments. The resistance was characterized by evaluating symptom appearance and virus titter through ELISA. Elicitors i.e., SA and BTH were applied at different concentrations to enhance the innate resistance of mungbean by the induction of defense related compounds. All treatments were helpful in reducing plant infection but the most effective treatment was the combination of SA@5mM and BTH@150mg/L as compared to virus inoculated control. Three weeks analysis showed peak accumulation of defense related enzymatic antioxidants and phenols in the mungbean leaves treated with SA and BTH. Higher enzymatic activity was observed in elicitor treated plants followed by inoculation with MYMV. As the resistance increased due to the application of SA & BTH the enzymatic activities of SOD, POD, and CAT were also increased during second week after application of elicitors. This study revealed that SA and BTH are potential source for management of MYMV by enhancing the level of protection through induction of systemic acquired resistance.
Systemic acquired resistance (SAR): A novel strategy for plant protection.mohd younus wani
Exclusive reliance on pesticides, fungicides and herbicides resulted in pesticide and herbicide, resistance, pest resurgence, residues, environmental pollution. Plants have developed various resistance mechanisms to help them adapt to pathogen and insect attack (Jones and Dangl, 2006). Systemic acquired resistance (SAR) is a form of induced resistance that is activated throughout a plant after being exposed to elicitors from virulent, avirulent, or nonpathogenic microbes, or artificial chemical stimuli such as chitosan or salicylic acid (SA) (Gozzo and Faoro, 2013).It is a mechanism of induced defense that confers long-lasting protection against a broad spectrum of microorganisms. SAR requires the signal molecule salicylic acid (SA) and is associated with accumulation of pathogenesis-related proteins, which contribute resistance to the plants.
They can be used as fungicide alternative without any threat of developing resistance and being safe and ecofriendly (Najar et al, 2010). The elicitor, β-Amino butyric acid induces greater systemic resistance to mulberry in addition to enhancement in biochemical parameters and NPK contents of mulberry leaves (Mazal, 2014).Therefore, in order to control the diseases of mulberry without adverse effect on environment, humans and silkworms health attention needs to be given to promote SAR chemicals. A model needs to be framed to promote the use of these chemicals in order to make sericulture more profitable. This is an ecofriendly approach of disease and pest management. The chitinase genes of mulberry induced by insect wounding and fungal infection, suggesting that these chitinases help the mulberry plant to cope with the challenges from insects and fungi (Wang et al., 2015). Jasmonic acid (JA) is an important plant defense signal mediating resistance to herbivores.
Presently disease control is largely depends on the use of fungicides, bactericides and insecticides. The hazardous nature of these chemicals on the environment, human health and silkworm strongly necessitates the search for new, harmless means of disease control.Induced resistance like SAR can diminish the use of toxic chemicals for disease control and thus could be proposed as an alternative, non-biocidal, ecologically-friendly approach for plant protection and hence for sustainable Sericulture. Induced resistance is increased expression of Natural defense mechanisms against different pathogens provoked by external factors of various types. Systemic acquired resistance (SAR) is a "whole-plant" resistance response and can be distinguished from other disease resistant responses by both the spectrum of pathogen protection and the associated changes with gene expression.
Prime-ome: "A molecular approach towards defense priming"Dhanya AJ
Prime-ome is the entire set of messenger RNA (mRNA) molécules or transcripts, proteins and metabolites produced or modified by an organism or system during the different stages of priming in plants and prime-omics is the study of prime-ome.
Molecular basis of plant resistance and defense responses to pathogensSenthil Natesan
In response to pathogen attack, plants have evolved sophisticated defense mechanisms to delay or arrest pathogen growth.Unlike animals, plants lack a circulating immune system recognizing microbial pathogens. Plant cells are more autonomous in their defense mechanisms and rely on the innate immune capacity of each cell and systemic signals that disseminate from infection sites (Jones and Dangl, 2006). Plant innate immunity consists of preformed physical and chemical barriers (such as leaf hairs, rigid cell walls, pre-existing antimicrobial compounds) and induced defenses. Should an invading microbe successfully breach the pre-formed barriers, it may be recognized by the plant, resulting in the activation of cellular defense responses that stop or restrict further development of the invader.
Host-pathogen Interactions, Molecular Basis and Host Defense: Pathogen Detect...QIAGEN
Host–pathogen interactions are strikingly complex during infection. This slidedeck provides an overview of the molecular basis of these intricate interactions: the impact of microbiota on innate and adaptive immunity, metabolism, and insulin resistance and host defense mechanisms. Various research tools will be introduced to simplify and streamline each step of studying the host response, enabling detection of pathogens, analysis of gene expression and regulation, epigenetic modification, genotyping and signal transduction pathway activation.
— The diseases caused by bipartite Begomoviruses have emerged as overwhelming problem in various cropping systems of Pakistan. The study was conducted to evaluate the potential of induced resistance in mungbean to Mungbean yellow mosaic virus (MYMV) disease. In this work, resistance to MYMV infection was induced in mungbean plants by activating the Salicylic acid (SA) pathway using SA and Benzothiadiazole (BTH) as treatments. The resistance was characterized by evaluating symptom appearance and virus titter through ELISA. Elicitors i.e., SA and BTH were applied at different concentrations to enhance the innate resistance of mungbean by the induction of defense related compounds. All treatments were helpful in reducing plant infection but the most effective treatment was the combination of SA@5mM and BTH@150mg/L as compared to virus inoculated control. Three weeks analysis showed peak accumulation of defense related enzymatic antioxidants and phenols in the mungbean leaves treated with SA and BTH. Higher enzymatic activity was observed in elicitor treated plants followed by inoculation with MYMV. As the resistance increased due to the application of SA & BTH the enzymatic activities of SOD, POD, and CAT were also increased during second week after application of elicitors. This study revealed that SA and BTH are potential source for management of MYMV by enhancing the level of protection through induction of systemic acquired resistance.
Management of potato virus Y (PVY) in potato by some biocontrol agents under ...Open Access Research Paper
The study was conducted to test the activity of Pseudomonas fluorescens, Rhodotorula sp and fermented neem extract to protect potato plants against potato virusY disease development under field conditions. Infected potato tubers were soaked in P. fluorescens, Rhodotorula sp suspensions and in fermented neem extracts separately and sown in the field in completely randomized block design. The development of virus symptoms and the accumulation of virus in the plant based on Enzyme Linked Immunosorbent Assay (ELISA) were followed. The results obtained showed that the treatment of potato tubers with the three agents have significantly accelerated plant emergence, 5-6 days early than non treated ones, and improved plant growth, the plant dry weights ranged from 120-177 g/plant compared to 42 g/plant in non treated plants. The enhancement of plant growth was found associated with reduction in disease severity based on symptoms development and restriction of virus concentration as proved by ELISA absorbance of 405 nm, 0.14-0.23 compared with 2.50 in non treated plants. The results indicated that the use of bioagent to induce systemic resistance provide an efficient tool, as insecticide alternative to manage potato virus Y in potato. Check out more by following link https://innspub.net/management-of-potato-virus-y-pvy-in-potato-by-some-biocontrol-agents-under-field-conditions/
Pathogenesis-related proteins (initially named “b” proteins) were discovered in tobacco leaves
hypersensitively reacting to TMV by two independently working groups (Van Loon and Van Kammen,
1970; Gianinazzi et al., 1970)
Management of host plant resistance through immunizationAnshul Arya
it is a small presentation prepared for seminar purpose .immunization is a new technique very few people know about it even i did not get any slide prepared by it earlier even whatever i got was not purchased .so i prepared it for those who are interested to know about it without having problems to find the matter for it.
Biotechnology and disease management with special reference toSarda Konjengbam
Plant biotechnology can be defined as the use of tissue culture and genetic engineering techniques to produce genetically modified plants that exhibit new or improved desirable characteristics.
PLANT BIOTECHNOLOGY HELPS PLANT PATHOLOGY IN MANY WAYS.
Plant phenolics are secondary metabolites that encompass several classes structurally diverse of natural products biogenetically arising from the shikimate-phenylpropanoids-flavonoids pathways. Plants need phenolic compounds for pigmentation, growth, reproduction, resistance to pathogens and for many other functions. Therefore, they represent adaptive characters that have been subjected to natural selection during evolution. Plants synthesize a greater array of secondary compounds than animals because they cannot rely on physical mobility to escape their predators and have therefore evolved a chemical defence against such predators. This article, after a short review of plant phenols and polyphenols as UV sunscreens, signal compounds, pigments, internal physiological regulators or chemical messengers, examines some findings in chemical ecology concerning the role of phenolics in the resistance mechanisms of plants against fungal pathogens and phytophagous insects.
RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression, typically by causing the destruction of specific mRNA molecules. Historically, it was known by other names, including co-suppression, post-transcriptional gene silencing (PTGS), and quelling. Only after these apparently unrelated processes were fully understood did it become clear that they all described the RNAi phenomenon. Andrew Fire and Craig C. Mello shared the 2006 Nobel Prize in Physiology or Medicine for their work on RNA interference in the nematode worm Caenorhabditis elegans, which they published in 1998. Since the discovery of RNAi and its regulatory potentials, it has become evident that RNAi has immense potential in suppression of desired genes. RNAi is now known as precise, efficient, stable and better than antisense technology for gene suppression. Two types of small ribonucleic acid (RNA) molecules – microRNA (miRNA) and small interfering RNA (siRNA) – are central to RNA interference. RNAs are the direct products of genes, and these small RNAs can bind to other specific messenger RNA (mRNA) molecules and either increase or decrease their activity, for example by preventing an mRNA from producing a protein. RNA interference has an important role in defending cells against parasitic nucleotide sequences – viruses and transposons. It also influences development.
The simplest virions consist of two basic components: nucleic acid (single- or double-stranded RNA or DNA) and a protein coat, the capsid, which functions as a shell to protect the viral genome from nucleases and which during infection attaches the virion to specific receptors exposed on the prospective host cell.
Rhizobia are symbiotic diazotrophs (prokaryotic organisms that carry out dinitrogen fixation) that form a symbiotic association with legumes. This association is symbiotic in that both the plant and rhizobia benefit. The plant supplies the rhizobia with energy in the form of amino acids and the rhizobia fix nitrogen from the atmosphere for plant uptake. The reduction of atmospheric dinitrogen into ammonia is the second most important biological process on earth after photosynthesis (Sylvia, 2005). The actual process of dinitrogen fixation can only be carried out by diazotrophs that contain the enzyme dinitrogenase. Nitrogen is the most critical nutrient needed to support plant growth. Unfortunately, atmospheric dinitrogen (78% of air we breathe) is extremely stable due to triple bonds which can only be broken by energy intensive ways. These include electrical N2 fixation by lightning where oxides of N come to ground with rain, the Haber-Bosch process in industrial fertilizer production, and biological N2 fixation in legumes by bacterial symbionts such as Rhizobium etli. Biological fixation of nitrogen was the leading form of annual nitrogen input until the last decade of the 20th century (Russelle, 2008). It is gaining attention once again as sustainability becomes a central focus to feed a world population of over 7 billion people.
Soil organic matter has long been recognized as one of the most important components in maintaining soil fertility, soil quality, and agricultural sustainability. The soil zone strongly influenced by plant roots, the rhizosphere, plays an important role in regulating soil organic matter decomposition and nutrient cycling. Processes that are largely controlled or directly influenced by roots are often referred to as rhizosphere processes. These processes may include exudation of soluble compounds, water uptake, nutrient mobilization by roots and microorganisms, rhizosphere-mediated soil organic matter decomposition, and the subsequent release of CO2 through respiration. Rhizosphere processes are major gateways for nutrients and water. At the global scale, rhizosphere processes utilize approximately 50% of the energy fixed by photosynthesis in terrestrial ecosystems, contribute roughly 50% of the total CO2 emitted from terrestrial ecosystems, and mediate virtually all aspects of nutrient cycling. Therefore, plant roots and their rhizosphere interactions are at the center of many ecosystem processes. However, the linkage between rhizosphere processes and soil organic matter decomposition is not well understood. Because of the lack of appropriate methods, rates of soil organic matter decomposition are commonly assessed by incubating soil samples in the absence of vegetation and live roots with an implicit assumption that rhizosphere processes have little impact on the results. Our recent studies have overwhelmingly proved that this implicit assumption is often invalid, because the rate of soil organic matter decomposition can be accelerated by as much as 380% or inhibited by as much as 50% by the presence of live roots. The rhizosphere effect on soil organic matter decomposition is often large in magnitude and significant in mediating plant-soil interactions.
The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into various chemical forms as it circulates among the atmosphere and terrestrial and marine ecosystems. The conversion of nitrogen can be carried out through both biological and physical processes. Important processes in the nitrogen cycle include fixation, ammonification, nitrification, and denitrification. The majority of Earth's atmosphere (78%) is nitrogen, making it the largest pool of nitrogen. However, atmospheric nitrogen has limited availability for biological use, leading to a scarcity of usable nitrogen in many types of ecosystems. The nitrogen cycle is of particular interest to ecologists because nitrogen availability can affect the rate of key ecosystem processes, including primary production and decomposition. Human activities such as fossil fuel combustion, use of artificial nitrogen fertilizers, and release of nitrogen in wastewater have dramatically altered the global nitrogen cycle.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
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A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...
Defensins: Antimicrobial peptide for the host plant resistance
1.
2. Speaker
S. V. Pawar
Ph.D. (Ag.) II year
Dept. of Plant Pathology
Dr. P.D.K.V., Akola
Seminar Incharge
Dr. S. S. Mane
Professor and Head of Department
Dept. of Plant Pathology
Dr. P.D.K.V., Akola
3. • Plants are constantly exposed to several pests and pathogens
in nature.
• Plants have evolved a variety of different mechanisms like
physical barriers and biochemical compounds to cope with
constant threat posed by the pathogens.
• Defensins are small basic, cysteine-rich proteins with
antimicrobial activities
• Defensins constitute one of the largest families of small
antimicrobial peptides in plants.
4. • Defensins are the integral part of innate immune system an
ancient system that seems to prevail in all multicellular
organisms.
• Modern crop protection strategies against various pathogens
are based on exploiting the natural, intricate plant defense
mechanisms through transgenic approaches
• The ultimate aim of this is to reduce both the cost of crop
protection and the potentially detrimental impact of pesticides
on the ecosystems.
7. Defensins are small cationic peptides of 45-54 amino acid
residues with anti microbial activities that inhibit the growth of wide
range of phytopathogenic micro organisms which are distributed
throughout the plant kingdom.
o They are the new member of thionine family.
o Defensins are expressed in most but not all plants and are key
members of a plant’s immune system, which helps in protecting
the plants from various pathogens.
o They provide a first line of defense against pathogen attack.
8. Histor
y• First plant defensin
was isolated by
Mendez and colleagues
1990
• Plant defensin termed was
coined by Terras and
colleagues
1995
• Reported the use of defensin to
enhance the resistance to fungal
pathogen by Terras and colleagues
1995
8
10. Table 1: Biotic and Abiotic Stress induction of Plant
Defensin Expression
Lay and Anderson, 2005
Stress Plant defensin Plant source Tissue
Pathogen infection DRR230-a, DRR230-b Pisum sativum Immature pea pods
Rs-AFP3, Rs-AFP4 Raphanus sativus Leaves
DRR230-c Pisum sativum Leaves
PDF1.2 Arabidopsis thaliana Leaves
PDF2.3 Arabidopsis thaliana Leaves
FST Nicotiana tabacum Sepals
Wounding DRR230-c Pisum sativum Leaves
Drought Dhn8 Glycine max Leaves and roots
Salt NeThio1, NeThio2 Nicotiana excelsior Leaves
NpThio1 Nicotiana paniculata Leaves
Cold Tad1 Triticum aestivum Crown tissue and
young seedlings
11. Role of Defensins
Role in symbiotic interactions
Involvement of plant defensins in other stresses
Effect of defensins on root development
Role of defensins in reproductive organs
Role in defense response
12. Advantages
Defensins are expressed in various organs and provide a first line of
defense against pathogen attack.
Defensins work at level of innate non specific immunity against the
varied pathogens.
Nontoxic to most animal and plant cells.
Defenins are thermostable.
Defensins have shown satisfactory efficacy against pathogens.
• Overexpression of certain defensin gene causes the growth
abnormality.
• Complexity of translating laboratory results to field situations or the
difficulty in negotiating the regulatory requirements required for
experiment.
Limitations
14. 2. Expressed during normal plant growth and development.
3. Expression of defensin gene is developmentally regulated or in response
to biotic and abiotic stimuli.
4. All plant defensins described to date have a signal peptide marking the
protein for extracellular secretion.
1. They are produced by single gene.
5. Different biological activity.
16. Table 2: Various biological activities displayed by
the plant defensins
Sl.no Biological activity Examples Plant sources
1 Anti fungal Rs-AFP1-4
Ah-AMP1
AlfAFP1
Dm-AMP-1
Raphanus sativus
Aesculus hippocatanum
Medicago sativa
Dahalia merkii
2 Anti bacterial Pth-St1
Fabatin -1 and -2
SoD1-7
Solanum tuberosum
Vicia faba
Spinacia oleracea
3 Protein synthesis inhibitor γ1-H
γ1-P
Hordeum vulgare
Triticum turgidium
4 Amylase inhibitor SIα1-3 Sorghum bicolor
5 Proteinase inhibitor CfD2
Cp-thionin
Cassia fistula
Vigna unguiculata
6 Sodium channel inhibitor γ1-Z and γ2-Z Zea mays
Lay and Anderson, 2005
17. Classes of Defensins
ER signal peptide Defensin domin
ER signal peptide Defensin domin C- terminal prodomin
Lay and Anderson, 2005
Class I
Class II
N- terminal
N- terminal
18. Anti fungal plant defensins
Divided into two different subgroups:
Morphogenic defensins: Reduced hyphal elongation with a
concomitant increase in hyphal branching.
Ex: Rs-AFP1, Rs-AFP2
Nonmorphogenic defensins: Reduce the rate of hyphal
elongation, but do not induce marked morphological distortions.
Ex: Dm-AMP1, Dm-AMP2
19. Kaur et al., 2011
= Plant defensin
= Unidentified
receptor
= Sphingolipid
N = Nucleus
M = Mitochondria
V = Vacuole
Mode of action of Rs AFP2 defensin
20. Mode of action of Dahlia (Dm- AMP1)
Thevissen et al., 2003
21. Transgene Source
plant
Recipient plant(s) Increased resistance against test
organism(s)
Rs-AFP2 Radish Tobacco Alternaria longipes
Rs-AFP2 Radish Tomato, oil rape A. solani, Fusarium oxysporum, Phytophthora
infestans, Rhizoctonia solani, Verticillium dahliae
AlfAFP Alfalfa Potato V. Dahliae
Spi1 Norway
spruce
Tobacco, Norway
spruce embryonic
cultures
Erwinia carotovora, Heterobasidion annosum
DRR230-a Pea Canola Leptosphaeria maculans
DRR230-a
DRR230-c
Pea Tobacco Fusarium oxysporum, Asochyta
pinodes,Trichoderma reesei, Ascochyta lentis, F.
solani, L. maculans, Ascochyta pisi, Alternaria
alternata
BSD1 Chinese
cabbage
Tobacco Phytophthora parasitica
WT1 Wasabi Rice Magnaporthe grisea
Lay and Anderson, 2005
22.
23. Case study 1: Transgenic tomato plants containing MsDef1 showing resistance
to wilt caused by Fusarium oxysporum f.sp. lycopersici
Abdallah et al., 2010
MsDef1-transgenic tomato plants with three leaf stage into soil infested with
F. oxysporum f.sp. lycopersici showing no symptoms compared to the non-transgenic
control plants. The severe wilt symptoms appeared on control plants indicated by
arrows. (B) Dark brown vascular discoloration appeared in the stem of non-transgenic
plant and was absent in the transgenic plant.
24. Case study 2: Defensin (TvD1) exhibited strong anti-fungal activity against
Rhizoctonia solani in transgenic tobacco plants
Vijayan et al., 2013
Non-transgenic controls - 39 % LAD, Low-expression plant (T13) -7 % LAD, High-expression plants T1 -
2.5% LAD, T26-2 %LAD for leaf bioassay. For seedling assay the control plants showed the wilting
symptoms at the shoot and root junction where as transgenic plants showed high level of tolerance.
25. Case study 3: Bioassay of transgenic peanut plants containing defensin fusion
gene for early and late leaf spot diseases caused by Cercospora
arachidicola and Cercospora personata respectively
Madhu Bala et al., 2015
The top and bottom rows indicate disease development 10 and 21 days after inoculation.
Cultivar GG 20 was used as a nontransformed control, whereas TMV 2 and JL 24 were used as
susceptible controls. The number of lesions and lesion size were less in transgenic peanut lines
DEF 5 as compared with the control line
Early leaf spot disease
Late leaf spot disease
26. Case study 4 :Expression of Dm-AMP1 in rice confers resistance to
Magnaporthe grisea
When transgenic plants were challenged with M. grisea, there was a remarkable difference
in diseased leaf area (%DLA) between non-transformed (69.68±2.52) and transgenic lines
(11.12 ±0.65 to 18.35±1.74) at 99% confidence interval (CI).
Jha et al., 2009
27. Floral
development
stage
NaD2
(%)
NaD1 (%)
N. alata
floral
organ
NaD2 (%)
NaD1 (%)
1 0.35 2.3 Petals 0.04 0.14
2 0.26 1.8 Sepals 0.08 0.38
3 0.28 1.6 Anthers 0.01 0.13
4 0.17 1.6 Styles 0.02 0.13
5 0.08 0.4 Stigma 0.02 0.05
Ovaries 0.02 0.23
Table 5: Percentage of NaD2 and NaD1 in total protein extracts derived from
different stages of development from floral organs of Nicotiana
alata.
Peter et al., 2014
28. Conclusion
Defensins are widespread in plants and are expressed in tissues that
provide a first line of defense against potential pathogens.
.MsDef1 in tomato transgenic plant shows the resistance towards wilt
caused by Fusarium oxysporum f.sp. lycopersici.
Transgenics produced from the defensin gene Dm-AMP1 confirms
resistance to Magnaporthe grisea and Rhizoctonia solani in rice and
Phyptophthora palmivora in papaya.
Transgenic tobacco expressing ZmDEF1 exhibited anti fungal
activity against Phytophthora palmivora .
29. Transgenic peanut plants containing defensin fusion gene showed
less number of lesions and reduced lesion size caused by
Cercospora arachidicola and Cercospora personata.
NaD2 and NaD1defensin showed the inhibitory effect on
urediniospore germination in Puccinia coronata f. sp. avenae and
Puccinia sorghi.
Defensin (TvD1) exhibited strong anti-fungal activity in
transgenic tobacco plants against Rhizoctonia solani
The diversity and widespread occurrence of defensins in the
plant kingdom suggests they will be a rich source of proteins
with antimicrobial activities that have potential in agri
biotechnological applications.
