Characterization and induction kinetics of a putative candidate gene associated with downy mildew resistance in grapevine

摘要

Downy mildew in cultivated grapevines (Vitis spp.), caused by Plasmopara viticola, is a devastating disease that results in considerable economic losses as well as environmental damage due to the repeated application of fungicides. The molecular role of the NBS-LRR family is highly related to plant immune- activity against various pathogens and pests. In this study, the 5' and 3' ends of the resistance gene homology fragment, designated as RGA23, were obtained by rapid amplification of cDNA ends PCR (RACE-PCR), and a 2,789 bp full-length cDNA was obtained using the gene-specific primers based on the spliced sequence. The deduced 892 amino acid sequence of this cDNA contains a characteristic NBS-LRR domain of plant resistance genes and a coiled-coil (CC) region. We analyzed the expression of RGA23 under P. viticola infection and abiotic stress at different time points using real-time quantitative polymerase chain reaction (RT-qPCR). The results showed that P. viticola treatment and four tested abiotic stimuli, including SA, MeJA, ABA, and H2O2, triggered significant inductions of RGA23 within 12 d of inoculation. The results indicate that RGA23 may play a critical role in protecting grapevines against P. viticola through a signaling pathway triggered by P. viticola and these molecules.