Molecular aspects of avirulence genes of the tomato pathogen Cladosporium fulvum

1995 ◽  
Vol 73 (S1) ◽  
pp. 490-494 ◽  
Author(s):  
Pierre J. G. M. de Wit ◽  
Matthieu H. A. J. Joosten ◽  
Guy Honée ◽  
Paul J. M. J. Vossen ◽  
Ton J. Cozijnsen ◽  
...  
Keyword(s):  
Host Plant ◽  
Resistance Genes ◽  
Hypersensitive Response ◽  
Fungal Pathogens ◽  
Direct Interaction ◽  
Defense Responses ◽  
Cladosporium Fulvum ◽  
Avirulence Genes ◽  
Host Genotype ◽  
Gene For Gene

Host genotype specificity in interactions between biotrophic fungal pathogens and plants in most cases complies with the gene-for-gene model. Success or failure of infection is determined by the absence or presence of complementary genes, avirulence and resistance genes, in the pathogen and the host plant, respectively. Resistance, expressed by the induction of a hypersensitive response followed by other defence responses in the host, is envisaged to be based on recognition of the pathogen, mediated through direct interaction between products of avirulence genes of the pathogen (the so-called race-specific elicitors) and receptors in the host plant, the putative products of resistance genes. The interaction between the biotrophic fungus Cladosporium fulvum and its only host, tomato, is a model system to study fungus–plant gene-for-gene relationships. Here we review research on isolation, characterization, and biological function of two race-specific elicitors AVR4 and AVR9 of C. fulvum and cloning and regulation of their encoding genes. Key words: avirulence genes, race-specific elicitors, resistance genes, hypersensitive response, host defense responses.

Plant disease resistance genes: unravelling how they work

1995 ◽  
Vol 73 (S1) ◽  
pp. 495-505 ◽  
Author(s):  
Kim E. Hammond-Kosack ◽  
Jonathan D. G. Jones
Keyword(s):  
Resistance Genes ◽  
Plant Disease Resistance ◽  
Defense Responses ◽  
Host Responses ◽  
Cladosporium Fulvum ◽  
Avirulence Genes ◽  
In Planta ◽  
Molecular Events ◽  
Cf Resistance Genes ◽  
Avr Gene

Resistance (R) genes confer on a plant the ability to defend itself following microbial attack. Each R gene exhibits an extreme specificity of action and is only effective against a microbe that has the corresponding functional avirulence (Avr) gene. This article reviews the strategies and experimental approaches deployed to understand the molecular events underlying the specificity of action of various tomato Cf resistance genes that results in incompatibility to the fungal pathogen Cladosporium fulvum. Topics covered include the clustering of Cf genes, the biology of Cf-dependent incompatibility, the map-based and transposon tagging approaches used to clone the Cf-2 and Cf-9 genes, respectively, identification by mutagenesis of other plant loci required for full Cf-9 mediated resistance, the expression of a functional Avr9 gene in planta and its lethal consequences to Cf-9 containing plants, the physiological and molecular host responses to C. fulvum and AVR elicitor challenges and some genetic approaches to ascertain the crucial components of the defense response. Key words: Cladosporium fulvum, Lycopersicon esculentum, tomato leaf mold, Cf resistance genes, fungal avirulence genes, plant defense responses.

Effect of SnTOX effectors on the virulence degree of Stagonospora nodorum isolates

Biomics ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 343-351
Author(s):  
S.V. Veselova ◽  
G.F. Burkhanova ◽  
S.D. Rumyantsev ◽  
T.V. Nuzhnaya
Keyword(s):  
Host Plant ◽  
Transcriptional Activity ◽  
Susceptibility Gene ◽  
Stagonospora Nodorum ◽  
Quantitative Composition ◽  
Host Genotype ◽  
Mrna Accumulation ◽  
Gene System ◽  
Compatible Interactions ◽  
Gene For Gene

Stagonospora nodorum Berk. is the causal agent of Septoria nodorum blotch (SNB) of wheat (Triticum aestivum L.). It synthesizes host-specific necrotrophic effectors (NEs), which facilitate infection process and ensure virulence of pathogen on host plant with a dominant susceptibility gene. The interaction of virulence genes products of the NEs pathogen (SnTox) with susceptibility genes products of the host plant (Snn) in the S. nodorum - wheat pathosystem is carried out in inverted gene-for-gene system and causes the development of disease. In this study, we tested three main NEs SnToxA, SnTox1, SnTox3, which have already been identified in S. nodorum at the gene level. The NEs role in the development of SNB has already been proven; however, the overall host response to SNB does not always strictly follow the inverted gene-for-gene system, as multiple SnTox-Snn interactions can be additive or epistatic. In this regard, the aim of the work was to identify the NE genes in three S. nodorum isolates and to study effect of NEs genes transcriptional activity on the isolate virulence. We have shown that all three NEs SnToxA, SnTox3 and SnTox1 played an important role in the development of the disease in compatible interactions. Effectors SnTox3 and SnTox1 exhibited epistatic interaction that was removed by a triple compatible interaction (SnTox3-Snn3, SnToxA-Tsn1 and SnTox1-Snn1). This effect was shown by us for the first time. The mechanisms of epistatic and additive interactions, as well as the virulence of the isolate were associated with the regulation of the NEs genes transcriptional activity. The avirulent isolate Sn4VD lacked transcription of all three NEs genes, and the virulent isolate Sn9MH was characterized by a high level of mRNA accumulation of all three NEs genes during infection on susceptible cultivar. We also showed that SnTox expression depended both on the host genotype in SnToxA and SnTox3 and on the number of compatible interactions exhibiting additive or epistatic interactions in SnTox1 and SnTox3. Finally, the virulence of the S. nodorum isolate depended on the qualitative and quantitative composition of NEs.

Plant Resistance Genes for Fungal Pathogens - Physiological Models and Identification in Cereal Crops

1991 ◽  
Vol 46 (11-12) ◽  
pp. 969-981 ◽  
Author(s):  
Wolfgang Knogge
Keyword(s):  
Plant Defense ◽  
Resistance Genes ◽  
Fungal Pathogens ◽  
Plant Protection ◽  
Defense Responses ◽  
Avirulence Gene ◽  
Physiological Models ◽  
Plant Genes ◽  
Plant Pathogen Interaction

The complex biological phenomenon “resistance” can be reduced to single Mendelian traits acting on both the plant and the pathogen side in a number of pathosystems. According to the “gene-for-gene hypothesis”, the outcome of a plant/pathogen interaction in these cases is incompatibility if a plant carrying a particular resistance gene and a pathogen with the complementary avirulence gene meet. This suggests a causal role of resistance genes in a recognition process initiating active plant defense responses. Fundamentally different strategies are followed to identify these genes molecularly depending on the plant and pathogen species involved. Fungal diseases of crop plants, especially those of cereals, cause dramatic yield losses worldwide. It is assumed that a molecular characterization of plant genes conferring resistance to fungal pathogens will lead to a better understanding of the plant defense system in general permitting the development of new methods of crop plant protection.

Gene-for-gene relationships in the Avena: Puccinia graminis host–parasite system in Canada

1970 ◽  
Vol 48 (5) ◽  
pp. 969-975 ◽  
Author(s):  
J. W. Martens ◽  
R. I. H. McKenzie ◽  
G. J. Green
Keyword(s):  
North America ◽  
Resistance Genes ◽  
Stem Rust ◽  
Host Population ◽  
Puccinia Graminis ◽  
Physiologic Race ◽  
Host Genotype ◽  
Physiologic Races ◽  
Host Parasite ◽  
Gene For Gene

The results of 48 years of oat stem rust physiologic race surveys are interpreted in terms of the prevailing host genotype. Changes in the frequencies of genes that govern virulence in the pathogen can be explained only in part by changes in the resistance genes carried by the host population. Genes for virulence on newly released types of resistance have spread very quickly through the rust population, after initial 'breakdown' of the resistance. The most successful physiologic races carry genes for virulence in excess of those required for successful parasitism in North America. Many races carry genes for virulence on types of resistance that have never been used on this continent.

scholarly journals Direct protein interaction underlies gene-for-gene specificity and coevolution of the flax resistance genes and flax rust avirulence genes

2006 ◽  
Vol 103 (23) ◽  
pp. 8888-8893 ◽  
Author(s):  
P. N. Dodds ◽  
G. J. Lawrence ◽  
A.-M. Catanzariti ◽  
T. Teh ◽  
C.-I. A. Wang ◽  
...  
Keyword(s):  
Protein Interaction ◽  
Resistance Genes ◽  
Avirulence Genes ◽  
Gene For Gene

scholarly journals Novel Mutations Detected in Avirulence Genes Overcoming Tomato Cf Resistance Genes in Isolates of a Japanese Population of Cladosporium fulvum

PLoS ONE ◽  
2015 ◽  
Vol 10 (4) ◽  
pp. e0123271 ◽  
Author(s):  
Yuichiro Iida ◽  
Pieter van ‘t Hof ◽  
Henriek Beenen ◽  
Carl Mesarich ◽  
Masaharu Kubota ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Japanese Population ◽  
Cladosporium Fulvum ◽  
Avirulence Genes ◽  
Novel Mutations ◽  
Cf Resistance Genes
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