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Cucumber blight caused by Phytophthora melonis is one of the most serious diseases of cucumber in south China, and causes significant losses for cucumber production.WRKY is a significant transcription factor family which are widely involved in plant disease resistance reaction.However, so far, there are no reports about WRKY transcription factors involved in cucumber disease defense reaction.To investigate the possible involvement of CsWRKYs in cucumber response to P.melonis infection,we performed a systematic analysis of expression profiles of 54 CsWRKYs by real time-PCR in susceptible cultivar B80 (compatible) and resistant cultivar JSH (incompatible) inoculated by P.melonis.Our results revealed that among 54 tested genes the expression of 18 genes was increased remarkably in both compatible and incompatible interactions between cucumber and P.melonis.In experiments with defense signaling molecules of SA and MeJA, very interestingly, 16 CsWRKYs among the 18 P.melonis-inducible genes were strong induced by SA, and only 3 CsWRKYs (CsWRKY13, CsWRKY42 and CsWRKY50)both responded to MeJA treatments.These results suggested that a majority of CsWRKYs involved in cucumber disease defense reaction though SA signaling pathway, some were co-regulated by both SA and JA (MeJA).