Differential expression of susceptible and tolerant grape cultivars on black rot infection

Abstract

The ascomycota fungus Guignardia bidwellii, responsible for the black rot disease of grapevine is causing increasing damages in Hungary especially in organic vineyards without chemical disease management. A wide range of mildew resistant cultivars are susceptible to black rot, while the interspecific hybrid variety ‘Csillám’ shows high tolerance/resistance against the disease. In a comprehensive RNAseq experiment transcriptomic responses have been assayed in the tolerant ‘Csillám’ and the susceptible Vitis vinifera variety ‘Csaba gyöngye’ (syn. ‘Perle von Csaba’). Infected and mock inoculated leaves have been sampled at 0hpi, 6hpi, 18hpi and 36hpi in three biological replicates. Forty-two RNA libraries have been sequenced on an Illumina platform (~300 bp insert size, 2×100 bp pair end sequencing). Primary analysis of the sequence data shows significant overlap with transcriptomic changes reported earlier after infection of grapevine with biotrophic fungi. Expression of basic elements of pathogen triggered immunity (such as PR protein genes, stilbene synthases and leucine rich receptor kinases, etc.) is significantly higher in the tolerant variety. On the other hand, resistance gene analogues are also represented between the differentially expressed genes. No gene of interest has been identified around a previously described QTL on linkage group 14, suggesting that the tolerance of ‘Csillám’ might differ from the resistance described earlier in the rootstock variety Börner.Text: