STRUCTURAL ORGANIZATION AND DIFFERENTIAL EXPRESSION OF 3 STILBENE SYNTHASE GENES LOCATED ON A 13-KB GRAPEVINE DNA FRAGMENT

A 13 kb DNA fragment was isolated from a grapevine (Vitis var. Optima) genomic library by hybridizing with elicitor-induced stilbene synthas e cDNA as a probe. After fragmentation with Eco RI, subcloning and seq uencing, two full-size stilbene synthase genes (Vst1 and Vst2) and the 3' end of a third stilbene synthase gene (Vst3) were located within t he 13 kb fragment. Vst1 and Vst2, differing only slightly in the codin g region, are distinguished in the intron size and in the structure of the promoter region. The 5' flanking region of gene Vst1 contains a T ATAA box at nucleotide -48. The substantial structural differences fou nd for the promoters of the two genes are paralleled by a striking dif ference in the expression of the two genes in elicitor-treated cells. Moreover, the accumulation upon elicitation of six different stilbene synthase mRNAs was studied and found to differ by two orders of magnit ude.