A molecular genetic perspective of reproductive development in grapevine

The grapevine reproductive cycle has a number of unique features. Inflorescences develop from lateral meristems (anlagen) in latent buds during spring and summer and enter a dormant state at a very immature stage before completing development and producing flowers and berries the following spring. Lateral meristems are unique structures derived from the shoot apical meristem and can either develop into an inflorescence or a tendril. How the grapevine plant controls these processes at the molecular level is not understood, but some progress has been made by isolating and studying the expression of flowering genes in wild-type and mutant grapevine plants. Interestingly, a number of flowering genes are also expressed during berry development. This paper reviews the current understanding of the genetic control of grapevine flowering and the impact of viticulture management treatments and environmental variables on yield. While the availability of the draft genome sequence of grapevine will greatly assist future molecular genetic studies, a number of issues are identified that need to be addressed--particularly rapid methods for confirming gene function and linking genes to biological processes and traits. Understanding the key interactions between environmental factors and genetic mechanisms controlling the induction and development of inflorescences, flowers, and berries is also an important area that requires increased emphasis, especially given the large seasonal fluctuations in yield experienced by the crop and the increasing concern about the effect of climate change on existing wine-producing regions.