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 ◽  
...  
1995 ◽  
Vol 73 (S1) ◽  
pp. 495-505 ◽  
Author(s):  
Kim E. Hammond-Kosack ◽  
Jonathan D. G. Jones

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.


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 ◽  
...  

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.


2016 ◽  
Vol 83 (4) ◽  
Author(s):  
V. Chellappan Biju ◽  
Like Fokkens ◽  
Petra M. Houterman ◽  
Martijn Rep ◽  
Ben J. C. Cornelissen

ABSTRACT Race 1 isolates of Fusarium oxysporum f. sp. lycopersici (FOL) are characterized by the presence of AVR1 in their genomes. The product of this gene, Avr1, triggers resistance in tomato cultivars carrying resistance gene I. In FOL race 2 and race 3 isolates, AVR1 is absent, and hence they are virulent on tomato cultivars carrying I. In this study, we analyzed an approximately 100-kb genomic fragment containing the AVR1 locus of FOL race 1 isolate 004 (FOL004) and compared it to the sequenced genome of FOL race 2 isolate 4287 (FOL4287). A genomic fragment of 31 kb containing AVR1 was found to be missing in FOL4287. Further analysis suggests that race 2 evolved from race 1 by deletion of this 31-kb fragment due to a recombination event between two transposable elements bordering the fragment. A worldwide collection of 71 FOL isolates representing races 1, 2, and 3, all known vegetative compatibility groups (VCGs), and five continents was subjected to PCR analysis of the AVR1 locus, including the two bordering transposable elements. Based on phylogenetic analysis using the EF1-α gene, five evolutionary lineages for FOL that correlate well with VCGs were identified. More importantly, we show that FOL races evolved in a stepwise manner within each VCG by the loss of function of avirulence genes in a number of alternative ways. IMPORTANCE Plant-pathogenic microorganisms frequently mutate to overcome disease resistance genes that have been introduced in crops. For the fungus Fusarium oxysporum f. sp. lycopersici, the causal agent of Fusarium wilt in tomato, we have identified the nature of the mutations that have led to the overcoming of the I and I-2 resistance genes in all five known clonal lineages, which include a newly discovered lineage. Five different deletion events, at least several of which are caused by recombination between transposable elements, have led to loss of AVR1 and overcoming of I. Two new events affecting AVR2 that led to overcoming of I-2 have been identified. We propose a reconstruction of the evolution of races in FOL, in which the same mutations in AVR2 and AVR3 have occurred in different lineages and the FOL pathogenicity chromosome has been transferred to new lineages several times.


2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 612-614
Author(s):  
N. Mironenko ◽  
O. Filatova ◽  
O. Afanasenko

Ascospore progeny of cross of Pyrenophora teres f. teres isolates was evaluated on virulence to three barley genotypes. Monogenic inheritance of virulence (26 a:17 v and 31 a:18 v) was shown to cultivar Harbin and accession c 21272 and supported by results of two fungal backcrosses. The existence of three unlinked avirulence genes to CI 4922 is suggested (37 a:7 v). The model of interaction between barley resistance genes and avirulence genes with postulated fungal genotypes is proposed.


2001 ◽  
Vol 14 (4) ◽  
pp. 508-515 ◽  
Author(s):  
Boris A. Vinatzer ◽  
Andrea Patocchi ◽  
Luca Gianfranceschi ◽  
Stefano Tartarini ◽  
Hong-Bin Zhang ◽  
...  

Scab caused by the fungal pathogen Venturia inaequalis is the most common disease of cultivated apple (Malus × domestica Borkh.). Monogenic resistance against scab is found in some small-fruited wild Malus species and has been used in apple breeding for scab resistance. Vf resistance of Malus floribunda 821 is the most widely used scab resistance source. Because breeding a high-quality cultivar in perennial fruit trees takes dozens of years, cloning disease resistance genes and using them in the transformation of high-quality apple varieties would be advantageous. We report the identification of a cluster of receptor-like genes with homology to the Cladosporium fulvum (Cf) resistance gene family of tomato on bacterial artificial chromosome clones derived from the Vf scab resistance locus. Three members of the cluster were sequenced completely. Similar to the Cf gene family of tomato, the deduced amino acid sequences coded by these genes contain an extracellular leucine-rich repeat domain and a transmembrane domain. The transcription of three members of the cluster was determined by reverse transcription-polymerase chain reaction to be constitutive, and the transcription and translation start of one member was verified by 5′ rapid amplification of cDNA ends. We discuss the parallels between Cf resistance of tomato and Vf resistance of apple and the possibility that one of the members of the gene cluster is the Vf gene. Cf homologs from other regions of the apple genome also were identified and are likely to present other scab resistance genes.


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