Contribution of a WRKY Transcription Factor, ShWRKY81 , to Powdery Mildew Resistance in Wild Tomato.

Tomato powdery mildew, caused by , is a destructive fungal disease that damages almost all of the aerial parts of tomato, causing devastating losses in tomato production worldwide. WRKY transcription factors are key regulators of plant immunity, but the roles of in wild tomato LA1777 against still remain to be uncovered. Here, we show that is an important WRKY transcription factor from wild tomato LA1777, contributing to plant resistance against . was isolated and identified to positively modulate tomato resistance against -Lz. The transient overexpression of the ShWRKY81-GFP (green fluorescent protein) fusion protein in cells revealed that ShWRKY81 was localized in the nucleus. responded differentially to abiotic and biotic stimuli, with mRNA accumulation in LA1777 seedlings upon -Lz infection. The virus-induced gene silencing of led to host susceptibility to -Lz in LA1777, and a loss of HO formation and hypersensitive response (HR) induction. Furthermore, the transcripts of were induced by salicylic acid (SA), and silenced LA1777 seedlings displayed decreased levels of the defense hormone SA and SA-dependent gene expression upon -Lz infection. Together, these results demonstrate that acts as a positive player in tomato powdery mildew resistance.