Abstract

Grapevine is an economically important crop throughout the world. However commonly cultivated species Vitis vinifera is susceptible to powdery mildew fungi. The objective of this study was to analyze the promoter of VvNAC36 transcription factor gene, which was induced by powdery mildew infection, as it was shown by previous microarray results. Analysis of VvNAC36 transcription factor promoter allows identifying the important cis-elements, which are responsible for gene regulation during infection. Knowing that the responsible cis-element of the gene is crucial for further study, the role of this gene is in powdery mildew infected grapevine. The study was performed using circumspect methodology. To confirm the presence of transgene in transgenic plants the PCR and glufosinate total herbicide application was used. The transplanted transgenic seedlings were infected with Golovinomyces orontii. To detect the GUS reporter gene expression, histochemical GUS staining and spectrophotometric assays were applied in each deletion variant. Finally the promoter sequence was analyzed by the PLACE (a database for PLAntCisacting Elements) program for identifying cis-elements. The results of the study showed significant difference in mock treated and induced expression in transgenic plants transformed with VvNAC36 promoter segments of different lengths, fused to GUS reporter gene. In basal expression level, the deletion variants 1178 bp and 257 bp differed significantly. Powdery mildew infection significantly increased the expression in all promoter variants, except the two shortest fragments. Based on the promoter motif analysis, it can be concluded, that the GT1-box (GAAAAA) supposed to have crucial role in regulating of VvNAC36 transcription factor gene during powdery mildew infection.

Keywords: VvNAC36 transcription factor; Powdery mildew; Gene expression; Cis-elements