Expression of WRKY and MYB genes during infection with powdery mildew in cucumber (<i>Cucumis sativus</i> L)

Abstract

The expression change pattern of three transcription genes (WRKY30, WRKY6 and MYB) in two cucumber lines with different powdery mildew resistance (resistant line ‘JIN5-508’ and susceptible line ‘D8’) were investigated during the infection process with powdery mildew using real-time quantitative polymerase chain reaction (RT-PCR). Gene expression analysis during different time points revealed that the expression ratio of WRKY30 was 10.08585 in D8 and 5.117667 in JIN5-508, respectively, and for WRKY6, the expression ratio was 5.396152 in D8 and 3.787322 in JIN5-508, respectively, and for MYB, the expression ratio was 14.17324 in D8 and 10.70195 in JIN5-508, respectively. Additionally, the time point of the highest relative expression ratio for the three genes was different in the two cucumber lines according to their resistance to powdery mildew, whereas the susceptible line D8 was earlier than the resistant line JIN5-508 in responding to the powdery mildew infection. We suggest that the three genes’ expressions induced by powdery mildew pathogen is related to the disease resistance, and the response of susceptible line is earlier and higher than the resistant line, which may have interactions between the three genes and other resistant genes.

Key words: Cucumber, powdery mildew, gene expression pattern.