This document reviews the current status of natural virus resistance genes and prospects for deploying these genes against virus infections. It discusses dominant resistance genes that confer monogenic resistance through recognition of viral avirulence factors. To date, 12 examples have been characterized that fall into the nucleotide binding site-leucine rich repeat class. Recessive resistance genes that cause impaired susceptibility by disrupting host factors required for virus infection are also described. These include mutations in translation initiation factors that cause resistance to various potyviruses and other viruses. Advances in genomics and molecular techniques are improving prospects for identifying and utilizing natural virus resistance genes in crop breeding programs.
Gene for gene system in plant fungus interactionVinod Upadhyay
MOLECULAR CHARACTERIZATION OF GENE FOR GENE SYSTEMS IN PLANT- FUNGUS INTERACTION AND THE APPLICATIONS OF AVIRULENCE GENES IN CONTROL OF PLANT PATHOGENS
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.
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.
Gene for gene system in plant fungus interactionVinod Upadhyay
MOLECULAR CHARACTERIZATION OF GENE FOR GENE SYSTEMS IN PLANT- FUNGUS INTERACTION AND THE APPLICATIONS OF AVIRULENCE GENES IN CONTROL OF PLANT PATHOGENS
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.
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.
The concept of gene for gene hypothesis was first developed by Flor in 1956 based on his studies of host pathogen interaction in flax, for rust caused by Melampsora lini. The gene for gene hypothesis states that for each gene controlling resistance in the host, there is corresponding gene controlling pathogenicity in the pathogen. The resistance of host is governed by dominant genes and virulence of pathogen by recessive genes. The genotype of host and pathogen determine the disease reaction. When genes in host and pathogen match for all loci, then only the host will show susceptible reaction. If some gene loci remain unmatched, the host will show resistant reaction. Now gene – for –gene relationship has been reported in several other crops like potato, sorghum, wheat, etc. The gene for gene hypothesis is also known as “Flor Hypothesis.”
The concept of gene for gene hypothesis was first developed by Flor in 1956 based on his studies of host pathogen interaction in flax, for rust caused by Melampsora lini. The gene for gene hypothesis states that for each gene controlling resistance in the host, there is corresponding gene controlling pathogenicity in the pathogen. The resistance of host is governed by dominant genes and virulence of pathogen by recessive genes. The genotype of host and pathogen determine the disease reaction. When genes in host and pathogen match for all loci, then only the host will show susceptible reaction. If some gene loci remain unmatched, the host will show resistant reaction. Now gene – for –gene relationship has been reported in several other crops like potato, sorghum, wheat, etc. The gene for gene hypothesis is also known as “Flor Hypothesis.”
Precision in Plant Immune Expression: Not Lost in Translation Kate Barlow
Xinnian Dong, HHMI Investigator, Arts & Sciences Professor of Biology, Duke University
• Expression of broad-spectrum disease resistance in plants often results in fitness penalty.
• Plant immune responses are normally regulated at both transcriptional and translational levels.
• Transcriptional and translational regulatory mechanisms of plant immune genes can be manipulated to engineer broad-spectrum resistance in crops.
Systemic Acquired Resistance (SAR) and it’s Significance in Plant Disease Ma...Ankit Chaudhari
Systemic Acquired Resistance (SAR) is a mechanism of induced defense that confers long-lasting protection against a broad spectrum of microorganisms and pests. Presently disease control is largely based on the use of hazardous chemicals viz., fungicides, bactericides and insecticides for either direct or indirect disease management. The hazardous natures of the products on the environment, human and animal health strongly necessitates the search for new safer means of disease control. SAR have high potential to diminish the use of toxic chemicals in the agriculture and has emerged as an alternative, non-conventional, non-biocidal and eco-friendly approach for plant protection and hence for sustainable agriculture. SAR requires the signal molecule salicylic acid (SA) and is associated with accumulation of pathogenesis-related proteins, which are thought to contribute to resistance.
Genome of Athelia rolfsii genome of ~65Mb having 20290 contigs. Annotation analysis revealed 16000 genes involved in fungicide resistance, virulence and pathogenicity along with and lethal genes.Genome have GC content 46.4%
History
Host pathogen interaction
R gene
Molecular techniques for detection of plant pathogens
Role of molecular techniques in resistance breeding Deployment of R genes and linked markers
Transgenic approaches in plant protection
Conclusion
Los días 7 y 8 de mayo organizamos en la Fundación Ramón Areces con la Fundación General CSIC el Simposio Internacional 'Microbiología: transmisión'. La "transmisión" en microbiología hace referencia al proceso por el que material genético es transferido de una célula a otra, de una población a otra. Es un proceso clave para entender el origen y la evolución de los seres vivos. El objetivo de esta reunión era conocer mejor la logística de la transmisión para ser capaces de modular o suprimir algunos procesos de transmisión dañinos.