GhMAKR在棉铃和种子发育中的功能研究

It is urgent to increase seed cotton yield in China where the arable land is limited. Three primary factors (boll number, boll weight and lint) determine seed cotton yield, which are closely associated to boll development. However, the molecular mechanisms of cotton boll development isn’t elucidated. In our previous studies, we cloned a gene named GhMAKR, specifically expressed in cotton bolls. In order to investigate the functions of GhMAKR in the development of cotton bolls, in this project, we plan to up-regulate and down-regulate the expression levels of GhMAKR in cotton; compare gene expression profile in bolls of transgenic plants between wild type; characterize the GhMAKR promoter regulatory elements; and reveal the relationship between GhMAKR and plant hormone. Our studies will demonstrate the functions and regulatory network of GhMAKR gene in boll development. The gene and the boll-specific promoter might be useful in gene engineering to improve the cotton yiled and quality.

在有限耕地资源的条件下提高棉花产量，是我国实现棉花稳产、高产迫切需要解决的问题。棉花产量因素主要包括铃数、铃重和衣分，三个因素均与棉铃的发育密切相关。然而目前有关棉铃发育分子机理的研究不多。课题组通过EST序列对比，获得了棉铃优势表达基因GhMAKR，启动子调控GUS表达进一步证实GhMAKR在棉铃中特异表达。为弄清GhMAKR在棉铃发育中的功能，本项目拟获得超量和RNAi抑制GhMAKR表达的转基因棉花，分析GhMAKR表达水平对棉铃的铃数、铃重，以及胚珠和纤维发育的影响；对比上调和下调GhMAKR转基因棉花棉铃发育的表达谱变化；分析GhMAKR启动子中棉铃特异表达的调控元件；研究GhMAKR与IAA、BRs等激素的关系；解析GhMAKR与棉铃发育的调控机制。本研究对弄清棉铃发育的分子机理有理论意义，还可为利用植物基因工程手段提高棉花产量和品质提供目的基因和组织特异启动子。

棉花是世界上最主要的天然纤维作物，棉花生产在我国国民经济中占有十分重要的地位。在有限耕地资源的条件下提高棉花产量，是我国实现棉花稳产、高产迫切需要解决的问题。棉花产量因素主要包括铃数、铃重和衣分，提高棉花产量离不开各组分之间的相互协调，三个因素均与棉铃的发育密切相关。然而目前有关棉铃发育分子机理的研究不多。课题组通过EST序列对比，获得了棉铃优势表达基因GhMAKR3，启动子调控GUS表达进一步证实GhMAKR3在棉铃中特异表达。利用果实优势表达启动子S7上调GhMAKR3基因的表达棉铃变小，种子百粒重降低。组成型抑制GhMAKR3基因表达转基因棉花种子的百粒重增重，种子中可溶性糖含量提高，纤维长度变长。BL和BRZ抑制剂能影响GhMAKR3表达水平，上调和下调GhMAKR3基因表达影响BRs信号传导途径相关基因的表达，结果说明GhMAKR3是一个棉铃优势表达基因，可能参与BRs信号传导过程。