柳树ZW性别决定系统发生机制研究

性别分化一直是植物学研究的热点。杨、柳是雌雄异株植物，起源于共同的祖先，但杨树（Chr.19）和柳树（Chr.15）的性染色体分别由不同常染色体进化而来，且杨树（XY）和柳树（ZW）性别决定系统不同。XY性别决定系统国际上已相对有深入研究，并已在不同植物中成功克隆了性别决定基因。具有ZW性别决定系统的植物很少，ZW性别决定系统是如何调控性别分化的？本项目旨在针对这一科学问题开展研究。柳树是少数具有ZW性别决定系统的植物。以簸箕柳为研究对象，申请人已完成性别决定位点精细定位。在此基础上，申请人拟通过家系连锁分析和自然群体关联分析相结合的方法，克隆簸箕柳性别决定基因；构建Z、W染色体性别决定基因区单倍型，解析性别决定基因区序列特征，阐明ZW性别决定系统发生机制；利用转录组、Small RNA、DNA甲基化测序等手段，阐明性别决定基因作用模式和表达特征；通过转化拟南芥，验证性别决定基因功能。

The genetic control of sex determination has always been a hot topic in biology research. Populus and Salix originated from a common paleotetrapolyploid ancestor, however, they have different sex-determining systems and different autosomes evolved into sex chromosomes in the sister genera. Thus far, many profound studies have been carried out on the XY sex-determining system and sex determination genes have been successfully cloned in some plants. In plants, species with ZW sex-determining system are less common, and it is still a question how the ZW system determines plant sex. The purpose of this project is to answer the scientific question. Willow is one of the few plants with ZW sex-determining system. We have accomplished fine mapping of gender loci in Salix suchowensis. Based on the previous work, we aim to clone the sex determination gene of S. suchowensis by combining linkage analysis and association analysis. Through reconstructing haplotypes of sex-determining region (SDR), we will further analyze the sequence characterization of the SDR and reveal the occurrence mechanism of the ZW sex-determining system. We will also characterize the function model and expression pattern of the sex determination gene using DNA methylome, transcriptome and small RNA sequencing. Additionally, we will verify the function of sex determination gene of S. suchowensis through the genetic transformation in Arabidopsis thaliana.