Promotion of Flowering by <i>JcFT</i> Depends On <i>JcLFY</i> in the Perennial Woody Species <i>Jatropha Curcas</i>

Production of normal gametes is necessary for flowering plant reproduction, which involves the transition from the vegetative stage to the reproductive stage and floral organ development. Such transitions and floral development are modulated by various environmental and endogenous stimuli controlled by sophisticated regulatory networks. FLOWERING LOCUS T (FT) and LEAFY (LFY) are genes that integrate signals from multiple genetic pathways in Arabidopsis. However, the comprehensive functions of and relationship between these two genes in trees are poorly understood. In this study, we found that JcFT plays a key role in regulating the transition from the vegetative stage to the reproductive stage in the perennial woody species Jatropha curcas. JcLFY is also involved in regulating the transition from the vegetative stage to the reproductive stage and floral organ development. The non–floral meristem-producing phenotype of JcFT-RNAi could be rescued by overexpression of JcLFY, while the abnormal flowers produced by JcLFY silencing were not rescued by JcFT overexpression. The results indicated that JcFT, in which a mutation lead to a nonflowering phenotype, is the central gene of the floral meristem transition and that JcLFY, in which a mutation leads to striking changes in flowering and often sterility, is the central floral development gene. Moreover, our hybridization results suggest that JcLFY acts downstream of JcFT in Jatropha.