Identification of genes involved in resistance to Didymella pinodes in pea by deepSuperSAGE genome-wide transcriptome profiling

Abstract

Didymella pinodes, causing ascochyta blight, is one of the most important pea pathogens. Despite the devastating consequences of this disease, very little is known about the mechanisms of resistance in the host. We employed the open2architecture transcriptome profiling technique deepSuperSAGE, coupled with next2generation sequencing, to identify pea2specific genes involved in the resistance to this important disease in the resistant Pisum sativum ssp. syriacum accession P665.Two deepSuperSAGE libraries were constructed from leaf RNA of infected and control plants, yielding a total of 17,561 different UniTags. 70% of them could be assigned to known sequences from pea or other plants. 509 UniTags were significantly differentially expressed (p < 0.05; fold change ≥ 2, ≤ 2) in inoculated versus control plants. This study provides a detailed picture of all expressed genes and metabolic pathways differentially regulated during D. pinodes3Pisum sativum interaction and contribute to the identification of candidate resistance genes. Protease inhibitors, antifungal compounds, strengthening of host cell walls, detoxification of D. pinodes toxins and repair of cell walls could contribute to resistance. Ethylene, ABA and indole232acetic acid pathways were up2, while the GA pathway was down2regulated.