The VviMYB80 Gene is Abnormally Expressed in Vitis vinifera L. cv. 'Zhong Shan Hong' and its Expression in Tobacco Driven by the 35S Promoter Causes Male Sterility

Anther development is a very precise and complicated process. In Arabidopsis, the AtMYB80 transcription factor regulates genes involved in pollen development and controls the timing of tapetal programmed cell death (PCD). In this study, we isolated and characterized cDNA for VviMYB80 expressed in flower buds of male-sterile Vitis vinifera L. cv. 'Zhong Shan Hong', a late-maturing cultivar derived from self-progeny of cv. 'Wink'. VviMYB80 belongs to the MYB80 subfamily and clusters with AtMYB35/TDF1 in a distinct clade. We found that in flower buds, expression of the VviMYB80 gene in cv. 'Zhong Shan Hong' sharply increased at the tetrad stage, resulting in a higher and earlier transcript level than that found in cv. 'Wink'. Expression of the VviMYB80 gene, driven by the 35S promoter, caused pleiotropic effects on the stamens, including smaller and shriveled anthers, delayed dehiscence, fewer seeds, shorter anther filaments, distorted pollen shape and a lack of cytoplasm, with the tapetum exhibiting hypertrophy in transformed tobacco. These results suggest that VviMYB80 may play an important role in stamen development and that expression of VviMYB80 driven by the 35S promoter in tobacco induces male sterility.