Recent studies have shown that the expression of genes related to the synthesis of flavonoids, such as the phenylalanineammonia lyase (PAL), chalcone synthase (CHS), chalcone isomerase (CHI), and stilbene synthase (STS) genes were induced in response to different signaling molecules and Botrytis cinerea inoculation in grapevine leaves. Therefore, in the present study, the nucleotide and deduced amino acid sequences of STS genes from cultivars Campbell Early and Kyoho were compared. The deduced amino acid sequences of VlKSTS12, VlKSTS11, VICESTS13, and VlKSTS1 showed 100 % homology to VlCESTS12, VlCESTS11, VICESTS24, and VlKSTS13, respectively, in Campbell Early and Kyoho. In addition, the maximum transcription was observed 6 h after chemical treatments. In Campbell Early, the transcription of PAL, CHS, and CHI was higher in leaves treated with ethephon than in those treated with hydrogen peroxide, methyl jasmonate, and salicylic acid. The PAL, CHS, and CHI genes were more induced in Campbell Early than in Kyoho. The mRNA content of STS genes started to increase at 6 h and peaked at 48 h after the treatments. In Kyoho leaves, the expression of STSs was highly up-regulated at 1 h and peaked at 6 h after the treatments. The expression of the STS genes was induced in both the cultivars in leaves inoculated with B. cinerea. STS11 and STS12 showed differential expression patterns from STS1, STS24, and STS13 in Campbell Early leaves inoculated with B. cinerea.
