拟南芥ROFL1调控花序分生组织的发育和花序结构的研究

不同种类植物的花序结构形态各异，既体现出开花植物的多样性，又表现了植物物种演化的多态性。花序的结构对作物产量也具有深远影响。但植物花序发育的调控机理目前仍不十分清楚。项目前期鉴定到一个在拟南芥花序中高表达的基因，该基因编码26S蛋白酶体的亚基，其功能缺失导致花序形态从十字花科植物的无限总状花序突变为茄科植物的有限聚伞花序。遗传分析显示，该基因影响花序分生组织决定基因TFL1的甲基化并调控其转录表达。因此将其命名为REGULATOR OF TFL1（ROFL1）。本项目拟深入研究ROFL1调节TFL1基因甲基化的遗传机制，建立ROFL1介导泛素蛋白酶体途径调控花序发育的分子遗传网络，并解析ROFL1调节十字花科和茄科植物花序结构变异的遗传基础。研究结果将为阐明植物花序分生组织的发育和花序结构调控的分子机制提供重要信息，并为生产上通过调节花序结构而提高作物产量提供重要的理论指导。

Flowering plants display an enormous morphological diversity of the inflorescence architectures, depending on the number of flowers that are formed and the position where flowers are initiated on the inflorescence axis. The development of inflorescence architectures has important effects on fruits and seeds production, and crop yield. However, a little is known on molecular mechanisms of the inflorescence development in plants. Based on the previous study, we identified a highly expressed gene in the inflorescences of Arabidopsis. This gene encodes a subunit of 26S proteasome, mutation of which results in the changes of the inflorescence architectures from the racemes of Brassicaceae into the cymes of Solanaceae, suggesting that it acts as a key regulator of the inflorescence development. Furthermore, the loss-of-function of this gene involves in the specific downregulation of the expression of inflorescence meristem identity gene TFL1 mediated by DNA hypermethylation. Thus, this gene is named as REGULATOR OF TFL1 (ROFL1). In this study, we will analyze the molecular mechanisms of ROFL1 acting in the regulation of DNA methylation in TFL1. We will establish a genetic and molecular framework of ROFL1-mediated ubiquitin–proteasome degradation for controlling inflorescence architectures in Arabidopsis. We will further prove that ROFL1 acts as a conservative factor that is responsible for the divergence of inflorescence architectures between Brassicaceae and Solanaceae. The results will provide the important information to understand the mechanisms of inflorescence architecture regulation and to improve crop yield.