Tendrils, inflorescences and fruitfulness: A molecular perspective

Abstract

Tendrils and inflorescences are closely related organs which both derive from the same meristematic structure known as an anlagen or uncommitted primordium. The close relationship between these two structures suggests that there is a control step at the gene level which directs the differentiation of an uncommitted primordium down the tendril or the inflorescence pathway, and that the process is quite plastic. To investigate this process at the molecular level a grapevine flowering model has been developed and will be used as a reference for testing grapevine homologues of Arabidopsis genes known to be involved in flowering. Differences between the flowering of Arabidopsis and grapevine suggest that for some genes, control and even function may differ in the vine. Juvenility and the absence of fruit during the initial years of growth is a feature of many perennial fruit crops, including grapevine. For juvenile grapevines, tendrils develop but inflorescences do not. Genotype-dependent and -independent strategies for overcoming the delay in flowering observed for both juvenile transgenic grapevine plants and progeny from breeding programs are discussed.