BeyondRgenes: dissecting disease-resistance pathways using genomics and proteomics

Abstract

Breeding for disease resistance in crops has mainly been accomplished by incorporating single resistance (R) genes. There are advantages to quantitative resistance in terms of durability but breeding for this type of resistance is difficult. New technologies in genomics and proteomics are providing insights into disease-resistance pathways. Structural genomics can identify genomic regions that carry genes controlling these pathways and provide a means for identifying and cloning the genes involved. High-throughput molecular breeding can be used to rapidly assess a large number of lines and select for multiple-resistance quantitative trait loci. This makes breeding for complex resistance types feasible. Functional genomics can identify genes involved in the resistance pathway. By merging structural and functional genomics it will be possible to correlate complex patterns of gene expression with genomic regions and identify key elements that control entire pathways. To fully understand the pathways it is necessary to look at posttranslational modification of proteins, as this is a fundamental mechanism involved in transducing the signal from the cell membrane to the nucleus to activate the resistance. Phosphoproteomics will help to discover proteins involved in the signalling pathways.Résumé : L'amélioration génétique des cultures pour la résistance aux maladies a été principalement accomplie par l'introduction de gènes de résistance (R) individuels. La résistance quantitative présente des avantages de durabilité, mais l'amélioration pour ce type de résistance est ardue. Les nouvelles technologies en génomique et en protéomique nous permettent de jeter un regard nouveau sur les voies métaboliques de résistance aux maladies. La génomique de structure permet d'identifier les régions du génome contenant des gènes qui contrôlent ces voies et nous offre la possibilité d'identifier et de cloner les gènes impliqués. L'amélioration moléculaire à haute capacité peut être utilisée pour rapidement évaluer de nombreuses lignées et pour sélectionner en fonction de plusieurs locus de caractère quantitatif. L'amélioration pour des types de résistance complexes est ainsi rendue possible. La génomique fonctionnelle permet d'identifier des gènes impliqués dans les voies métaboliques de résistance. En réunissant les génomiques de structure et fonctionnelle, il sera possible de faire le lien entre des schèmes complexes d'expression génétique et des régions du génome, et d'identifier les éléments clés qui contrôlent des voies entières. Pour bien comprendre les voies métaboliques, il est essentiel d'examiner les modifications post-traduction des protéines puisqu'il s'agit d'un mécanisme fondamental impliqué dans la transduction du signal de la membrane cellulaire au noyau afin d'activer la résistance. La phosphoprotéomique stimulera la découverte de protéines impliquées dans les voies de signalisation.

TaFLRS, a novel mitogen-activated protein kinase in wheat defence responses

“…Lr16 in wheat belongs to a group of R genes that are initiated upon plant-pathogen recognition mediated by a gene-for-gene interaction between a plant R gene product and a pathogen Avr gene product and the interaction leads to the activation of plant defence responses (Hammond-Kosack and Jones 1996;Jordan et al 2006;Rudd et al 2008). In this P. triticina-wheat interaction, the rapid TaFLRS transcriptional upregulation following the Lr16-BBB incompatible interaction was detected in 1.5 h but there was no significant change upon race TJB compatible interaction, suggesting that TaFLRS might be involved in the early defence response to leaf rust.…”

“…Plant defence responses depend on recognition of invading pathogens, and this recognition may occur via gene-for-gene interactions in which a plant resistance (R) gene product detects the action of a cognate pathogen avirulence (Avr) factor (Dangl and hypersensitive response (HR) at the site of infection with localized cell death, and significant amelioration of disease symptoms, and this plant-pathogen interaction has been long considered a model system in the analysis of wheat defence pathways (Kolmer 1996;Jordan et al 2006). Fusarium head blight (FHB) is also a serious disease of wheat worldwide that may cause substantial yield and quality losses (Gilbert et al 2006).…”

Proteomic analysis of the phytopathogenic soilborne fungusVerticillium dahliaereveals differential protein expression in isolates that differ in aggressiveness

“…Induction of pathogenesis‐related proteins is one of many plant defense responses against pathogens 6. Integration of knowledge from genomic studies, such as gene expression and functions, with proteomics‐based studies is an important combination in biology, in general, and towards plant disease resistance improvement in particular 7. Proteomics, based on a combination of 2‐DE followed by MS analysis, is a key research tool to study microbial pathogens in terms of their proteome maps, stage‐specific proteomics, and pathogenicity factors.…”

Wheat mitogen-activated kinase pathways in plant defense response

“…The presence of single leaf rust resistance genes in near-isogenic lines confers resistance to avirulent races resulting in a hypersensitive response at the site of infection with localized cell death, and significant amelioration of disease symptoms (Kolmer, 1996). This plant-pathogen interaction has been long considered a model system in the analysis of wheat defense pathways (Jordan et al, 2006). and other small grains (Gilbert and Tekauz, 2000).…”