Chitin is a component of cell walls that is considered one of the major fungal pamps. Jun 29, 2010 despite this, the nutrients that enable pathogen growth are derived from host cells, and the host cytoplasm and organelles are important sites of molecular interaction. A major trait of hostpathogen interactions determining host range is genetic specificity, i. The ability of a pathogen to cause disease in a host plant is usually. In many plant pathogen interactions, the rapid onset of a plant defence response relies on a recognition process controlled by avirulence avr genes in the pathogen and the corresponding resistance r genes in the plant. The earliest report of a blastlike disease of rice oryza sativa in the literature is 1637 in china and, in the following years, in japan o u 1987. Understanding these mechanisms at the molecular level would help in developing strains with superior biocontrol properties. Genetics of plantpathogen interactions genetics of plantpathogen interactions ji, cheng. Some of it stems from basic surveys of disease in the field.
As the control of this disease is an urgent task for many countries, further understanding of the interaction between plants and v. Genetics of plant pathogen interactions specifying plant disease resistance brian j. The book offers an integrated overview of plantpathogen interactions. Recently, exchange of mrna and small noncoding rnas has been described between host and parasitic plants, such as cuscuta pentagona or tryphisaria versicolor westwood et al. Genetics of plantpathogen interactions sciencedirect. In the gene for gene interaction during plant defence, avirulence avr genes of pathogen are expressed to produce elicitors fig. Resistance is only expressed when a plant that contains a specific r gene recognizes a pathogen that has the corresponding avirulence gene upper left panel.
Genetics of hostpathogen interaction and breeding for durable. A model host plant to study plantpathogen interaction using rice false smut isolates of ustilaginoidea virens. Gene expression profiling in blastinfected rice leaves. Staskawicz department of plant and microbial biology, 111 koshland hall, university of california, berkeley, california 947203120 understanding the mechanistic basis of why a. We seek to develop and use an efficient method for acquiring molecular population. In many plantpathogen interactions, the rapid onset of a plant defence response relies on a recognition process controlled by avirulence. Genetics and utilization of pathogen resistance in plants. The disease on rice, rice blast, is of enormous economic importance and biological interest. Toxins in plant pathogenesis toxins in plant pathogen interaction. To understand the interaction between a fungal plant pathogen and its host plant population, it is necessary to have genetic information for both populations, but little work has been done to characterize the population genetics of wild plant pathogens.
Continua in plant hostpathogen interactions 514 iii. Pdf plant pathogen interactions the name itself instills immense interest in mind of a reader as to what this title beholds. Goals objectives the objective of this project is the identification of genes in pathogens and host plants that determine the interactions between plant and pathogen. The interaction between plant and pathogen may develop by two ways given below. As he explains, plants have resistant genes, which trigger the immune response after pathogenic infections effectortriggered immunity. Genetics of plant pathogen interactions univ of wisconsin. This can occur through foodborne intoxication where the causative agent produces toxins in the body e.
The dominant genetic paradigm of plant pathogen interaction derives from. Progress has occurred in understanding the function of diseaseresistance genes that govern the resistance of plants to pathogens, and pathogenproduced. Host pathogen interaction an overview sciencedirect topics. This book describes the genetics, biochemistry, and epidemiology of host pathogen interactions in plant disease, especially as they concern the breeding of crops for disease resistance. A rust disease involves a very intimate interaction between the host and an obligate pathogen. The process of pathogenesis the onset of diseased condition in plants is facilitated by many factors such as virulence of the pathogen, susceptibility of the host, presence of suitable environmental conditions and various enzymes and metabolites of pathogens. This book describes the genetics, biochemistry, and epidemiology of hostpathogen interactions in plant disease, especially as they concern the breeding of crops for disease resistance.
Biological and biomedical implications of the coevolution of pathogens and their hosts mark e. However, the proposed framework suggested a need to reexamine the terms used to define the outcomes of host microbe interactions. This bacterium is able to colonize the rectum of susceptible worms and induces a defensive tailswelling response in the host. Occurrence of disease requires three now four basic elements, a susceptible host, a virulent pathogen and suitable environmental conditions fourth component proper time of interaction. Hostpathogen interaction disease is a disfunction of normal physiological processes in plants caused by microorganisms or an abiotic factor. Plants can play host to a wide range of pathogen types including viruses, bacteria, fungi, nematodes, and even other plants. The host pathogen interaction is defined as how microbes or viruses sustain themselves within host organisms on a molecular, cellular, organismal or population level.
Levin 5 coevolution between host and pathogen is, in principle, a powerful determinant of the biology and genetics of infection and disease. Population genetics of plant pathogens considers the origin, maintenance and distribution of genetic variation under the influence of mutation, gene flow, recombination, genetic drift and selection. Hosts, parasites and pathogens, university of warwick, uk, 68 april 2000. The recognition process during the interaction between host and the pathogen represents a signalsensor reaction i. Although the impacts of crop domestication on specialist pathogens are well known, less is known about the interaction of crop variation and generalist pathogens. The genetics of hostpathogen interactions springerlink. Genetics of plantpathogen interactions specifying plant.
The result of the interaction can lead to differential selection in either the host or the pathogen. Molecular basis of host pathogen interaction 37 extracellular surface receptors, which are involved in the detection of pathogen associated molecular patterns pamps to trigger immune responses. Pdf despite substantial advances in plant disease control strategies, our global food supply is still threatened by a multitude of pathogens. Staskawicz department of plant and microbial biology, 111 koshland hall, university of california, berkeley, california 947203120 understanding the mechanistic basis of why a certain pathogen causes disease in one host plant and. Unstable epidemic systems maintain more resistance genes, fewer virulence genes, and less overall genetic diversity than stable endemic diseases. Pathogen defence in plants a biological and molecular view two types of plant resistance response to potential pathogens.
Based on the concept that host damage was the most relevant outcome of the hostpathogen interaction, we proposed revisions to the definitions of the terms pathogen, pathogenicity, and virulence. This term is most commonly used to refer to diseasecausing microorganisms although they may not cause illness in all hosts. Geneforgene interactions specify plant disease resistance. Interactions of tomato and botrytis cinerea genetic diversity. Flor published his seminal work on the genetics of the interaction between flax and its obligate rust pathogen, malamspora lini, that we gained a substantial understanding of the genetic interactions that control disease resistance in plants 10. Mos1 mutagenesis reveals a diversity of mechanisms. Mechanisms of genetic variation alone are, however, often unsatisfactory to explain the compatibility between host and pathogen phenotypes 54, and nongenetic inheritance. The earliest report of a blastlike disease of rice oryza sativa in the literature is 1637 in china and, in the following years, in japan. Mar 18, 2015 hostpathogen interactions influence genetic diversity, and comparative genomic analyses are beginning to dissect genetic determinants involved in this process. Whole genome sequences are available for both rice 11, 12 and the blast fungus, so that the riceblast fungus interaction system offers to test the utility of genomic information for understanding hostpathogen interactions. Models of hostpathogen coevolution assume the presence of genetic variation for host resistance and pathogen infectivity, as well as genotypespecific interactions. The ability of a pathogen to cause disease in a host plant is usually the excep tion, not the rule. The evolutionary genetics of plantpathogen systems oxford.
Continua of specificity and virulence in plant hostpathogen. A pathogen that causes diseases is termed virulent a pathogen that does not cause diseases is termed avirulent types of pathogen. The phytohormone ethylene is a principal modulator in many aspects of plant life, including various mechanisms by which plants react to pathogen attack. At a recent meeting of the genetical societygenetical society spring meeting. Objective introduction pathogen plant defence elictors induced defence systemic defence pathogen related protein secondary compounds communal resistance 3. Biological and biomedical implications of the coevolution of. The genetic polymorphism maintained by hostpathogen coevolution is analysed in a multilocus model. This is the type of resistance needed in the 21st century to ensure food security. Blast disease is a devastating rice disease caused by the ascomycete fungus m.
Plants, in nature, are generally resistant to most pathogens. Plant pathogen interaction an overview sciencedirect topics. Hostinduced gene silencing in the obligate biotrophic. This includes the identification of interactions between genes within each organism as well as between organisms. Hostpathogen interactions in plant disease 1st edition. However, the proposed framework suggested a need to reexamine the terms used to define the outcomes of hostmicrobe interactions. Induced ethylene biosynthesis and subsequent intracellular signaling through a single conserved pathway have been well characterized.
Infectious diseases result from the interplay between the pathogens and the defenses of. Hugh information regarding genetics of plant disease is present inchapter 4 of 5th edition of plant pathology. Hr also contributes to the establishment of the longlasting systemic acquired resistance against subsequent attack by a broad range of normally virulent pathogens. Arabidopsis thaliana, endophytic colonization, plantpathogen interaction, plant defensin gene, pr genes, ustilaginoidea virens. Fungi can promote or inhibit plant growth, which is important. The filamentous fungus can cause disease on many species of the grass poaceae family.
Hostpathogen interactions are the interactions that take place between a pathogen e. A major trait of host pathogen interactions determining host range is genetic specificity, i. This leads to a cascade of transcription factors consisting of primary ein3like regulators and downstream. Host pathogen interaction plants linkedin slideshare. The hostpathogen interaction is defined as how microbes or viruses sustain themselves within host organisms on a molecular, cellular, organismal or population level. The chapter describes approaches to obtain plants resistant against disease by means of genetic engineering by plantpathogen interaction models. As in fungal or oomycete pathogens, parasitic plants also form haustoria as feeding organs during their interaction with host plants. Leaf rust rust resistance stripe rust stem rust adult plant. Jan 12, 2015 host cell recognizes the bacterium and initiates programmed cell death to restrict the growth of the pathogen, which thus does not cause disease. It was apparent that, in terms of the sophistication and depth of our knowledge, and the power of the tools. Unstable epidemic systems maintain more resistance genes, fewer virulence genes, and. The molecular basis of the three ways interaction between plants. Hostpathogen interactions influence genetic diversity, and comparative genomic analyses are beginning to dissect genetic determinants involved in. Fungal plant pathogens have evolved diverse mechanisms for penetrating into host plant tissue, ranging from entry through natural plant openings to various mechanisms of direct penetration through the outer surface.
Sep 29, 2012 understanding these mechanisms at the molecular level would help in developing strains with superior biocontrol properties. Evolutionary insights into hostpathogen interactions from. Genetics of plantpathogen interactions specifying plant disease resistance brian j. The genetic polymorphism maintained by host pathogen coevolution is analysed in a multilocus model. What is hostpathogen initial interaction telling us. Ijms free fulltext an overview of the molecular genetics. Based on the concept that host damage was the most relevant outcome of the host pathogen interaction, we proposed revisions to the definitions of the terms pathogen, pathogenicity, and virulence. All other combinations lead to lack of recognition by the host, and the. Gene expression analysis of plant hostpathogen interactions. This kind of geneforgene interaction is something that animal geneticists can only dream of. Molecular plantmicrobe interactions mpmi publishes fundamental and advanced applied research on the genetics, genomics, molecular biology, biochemistry, and biophysics of pathological, symbiotic, and associative interactions of microbes, insects, nematodes, or parasitic plants with plants.
A model host plant to study plantpathogen interaction using rice false smut isolates of. Hostpathogen interaction may also result hypersensitivity of the host tissue, whereby rapid death of the affected cells prevents the further spreading of the pathogen due to shortage of nutrition. During the contact between plant and pathogenic microorganism, a particular chain of events is produced in the plant organism. Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus like organisms, phytoplasmas, protozoa, nematodes and. By definition, all pathogens damage their host to some extent. A pathogen that causes diseases is termed virulent a pathogen that does not cause diseases is termed avirulent types of pathogen based on effects. The model assumes geneforgene interactions of the type commonly observed between host plants and their fungal pathogens. Plant virushost interaction contains cuttingedge research in plant molecular virology, including pathogenic viroids and transport by insect vectors, interference with transmission to control viruses, and synergism, with pivotal coverage of rna silencing and the counterdefensive strategies used by viruses to overcome the silencing response in plants.
Previous mutant screens have identified multiple loci that affect this interaction. The plant is provided by a receptor that interacts with bacterial protein. The chapter describes approaches to obtain plants resistant against disease by means of genetic engineering by plant pathogen interaction models. Molecular aspects of plantpathogen interaction archana. Plant pathology also phytopathology is the scientific study of diseases in plants caused by pathogens infectious organisms and environmental conditions physiological factors. Notable plant viruses include the papaya ringspot virus which has caused millions of dollars of damage to farmers in hawaii and southeast asia, 19 and the tobacco mosaic virus which caused scientist martinus beijerinck. Using this framework, we describe and contrast the genetic and environmental. Pdf genetics of plantpathogen interactions and resistance.
Despite this, the nutrients that enable pathogen growth are derived from host cells, and the host cytoplasm and organelles are important sites of molecular interaction. Ebwr9 is the corresponding r gene locus in brinjal. Janet morrison plantpathogen interactions department of. While the genetic basis of the hostpathogen interaction fits the criteria for coevolution, the time frame does not appear to be consistent with cospeciation. Genetic engineering is based on the technology enabling construction of genetic structures in the form of the socalled recombinant hybrid molecules dna or rna in laboratory conditions. The role of ethylene in hostpathogen interactions annual. Shengyang he explores plantpathogen interactions and provides an overview of a plants basic immunological responses. Jun 01, 2005 while the genetic basis of the host pathogen interaction fits the criteria for coevolution, the time frame does not appear to be consistent with cospeciation. Coevolutionary genetics of plants and pathogens springerlink. To study how genetic variation within a crop affects plant resistance to generalist pathogens, we infected a collection of wild and domesticated tomato accessions with a genetically diverse population of the generalist pathogen. It discusses all the steps in the pathway, from the microbehostcell interface and the plants recognition of the microbe to the plants defense response and biochemical alterations to achieve tolerance resistance. Host cell recognizes the bacterium and initiates programmed cell death to restrict the growth of the pathogen, which thus does not cause disease.
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