番茄果实重量基因FW11.3控制细胞大小的分子机理研究

Tomato fruit weight is an important agronomic trait. It relates to fruit quality and yield, so it is one of the most important goals of tomato domestication and breeding. Tomato fruit weight is a quantitative trait. The cloning and molecular function analysis of major QTL genes controlling fruit weight will pave the road to investigate the molecular basis of tomato domestication and fruit development, which will provide directions for the genetic improvement of tomato fruit weight. The applicant of this project has been studying the domestication and genetic improvement of tomato fruit weight for many years. Recently, the applicant identified the Fruit Weight 11.3 (FW11.3) gene, a major QTL gene controlling fruit weight in tomato, through map-based cloning. Tomato fruit weight is determined by locule number, cell number and cell size. FW11.3 might be the first tomato fruit weight QTL gene found to control the cell size of fruit. FW11.3 encodes an unknown function protein. It is expressed much higher in columella than in pericarp. However, its mutant, fw11.3, increases cell size in pericarp. This project will ⑴ detect the cell specific expression pattern of FW11.3 gene in tomato fruit and the subcellular localization of FW11.3 protein; ⑵ determine the biological process of fruit cell size regulation FW11.3 protein involved, through comparing the cell structure, DNA ploidy, hormone, transcriptome and metabolome of the fruit of wild type, fw11.3 near isogenic line, and transgenic line; ⑶ figure out the role of FW11.3 protein in the biological process of fruit cell size regulation. The results of this project will not only help us to understand the molecular mechanisms controlling cell size in tomato fruit, but also provide an important genetic recourse for tomato improvement.

果实重量是番茄重要的农艺性状，决定着番茄品质和产量，是驯化和育种的重要目标性状。果实重量主效基因的克隆与功能分析，对于阐明番茄驯化和果实发育的分子机制、指导番茄遗传改良具有重要的理论和育种价值。申请人长期从事番茄果实重量驯化与分子改良研究，最近我们克隆了影响果实重量的主效基因FW11.3。番茄果实重量决定于心室数量、细胞数量和细胞大小。FW11.3基因可能是目前克隆的第一个通过影响果实细胞大小来调控果实重量的QTL基因。FW11.3基因编码一个功能未知蛋白。它主要在果心部位表达。本项目拟在此基础上，深入研究：番茄果实发育过程中，FW11.3基因转录表达的细胞特异性及其蛋白表达、定位情况；确定FW11.3蛋白参与果实细胞大小调控的分子生物学途径；并在蛋白水平分析FW11.3蛋白在该途径中所处的环节及其作用。研究结果将有助于阐明果实细胞大小调控的分子机理，同时为番茄遗传改良提供重要的基因资源。