An-1调控水稻每穗粒数基因网络的构建

项目名称： An-1调控水稻每穗粒数基因网络的构建

项目编号： No.31471159

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 生物科学

项目作者： 罗江虹

作者单位： 中国科学院上海生命科学研究院

项目金额： 85万元

中文摘要： 每穗粒数是决定水稻产量的重要农艺性状，受到复杂的遗传机制调控。我们已报道An-1是一个调控每穗粒数的重要基因。An-1表达上调会引起细胞分裂素激活酶基因LOG表达下调，导致每穗粒数降低；反之，则每穗粒数上升。因此，An-1是一个每穗粒数的负调节因子，与细胞分裂素作用相拮抗。本研究前期预实验，通过对An-1上调表达的转基因植物及其亲本幼穗的转录组进行比较分析，获得差异表达基因133个。其中名为Small Panicle(SP)基因突变后导致每穗粒数减少，提示SP可能是参与穗粒数控制的An-1的下游基因。基于此，本项目拟通过mRNA原位杂交鉴定差异基因的表达模式，以确定受An-1调控且调节每穗粒数的候选基因，利用遗传学、细胞生物学和分子生物学手段鉴定其功能；进而阐明包括SP在内的候选基因与An-1及细胞分裂素之间的调控关系，从而建立以An-1、细胞分裂素及下游基因组成的每穗粒数的遗传调控网络。

中文关键词： An-1；每穗粒数；基因功能；细胞分裂素途径；基因调控网络

英文摘要： The grain number per panicle is directly associated with rice yield and regulated by the complicated genetic mechanism.The previous study showed that the An-1 encoded a basic helix-loop-helix transcription factor and regulated grain number per panicle in rice.Up-regulation of An-1 could down-regulate expression of LOG,an important cytokinin regulator, which caused reduction of grain number per panicle and yield per plant in transgenic plants, as compared with those in Nipponbare.Conversely, RNAi of An-1 in an indica variety Kasalath generated more grains per panicle than the control plants.Thus,An-1 is antagonistic to cytokinin and a negative regulator of grain number. Based on the preceding studies,NIP-AN1 transgenic plants were generated, in which grain number per panicle was reduced and almost no awn was formed as compared with that in Nipponbare.The An-1 expression was up-regulated and LOG expression was also down-regulated in NIP-AN1 transgenic plants.The transcriptomes of young panicles were then compared between Nipponbare and NIP-AN1 transgenic plants, using high throughput sequencing technique. Among the 133 differentially expressed genes, the genes involved in transcription regulation,phytohormone and signal transduction pathways have been selected and subjected to mRNA in situ hybridization to determine their spatio-temporal expression patterns. The preliminary study identified the Small Panicle (SP) gene, which was expressed in primary and secondary branch primordia and floral primordia.The sp mutant displayed reduced grain number per panicle as compared with wild type plants. According to the above results,the goal of this project are as follows: Firstly,the candidate genes will be determined by whether they are expressed in branch primordia and floral primordia,using mRNA in situ hybridization.Then,the functions of candidate genes in regulation of grain number per panicle will be confirmed by mutant and transgenic analysis.Furthermore, we will study the interactions between the candidate genes and investigate the relationship between candidate genes and An-1. We will also elucidate whether the candidate genes are regulated by cytokinin pathway.Finally,we will construct the gene regulatory network to regulate grain number per panicle,including An-1,cytokinin and candidate genes,and provide applicable information for rice molecular breeding.

英文关键词： An-1;grain number per panicle;gene function;cytokinin pathway;gene regulatory network