小麦抽穗期相关转录因子TaMYB72的功能分析

The optimum flowering time is an important agronomic trait for sustainable productivity and high yield potential of crops, therefore, discovering the heading date genes and analyzing their function are of theoretical significance and application value. In our previous works, many heading date related TFs were screened by using the platform of transfer the wheat TF genes into rice, in which TaMYB72 can make the heading date of transgenic rice 12-15 days earlier. In this work, we will decipher the effect of TaMYB72 on wheat heading date through series experiments. The transcriptional activation and DNA banding activity of TaMYB72 will be tested in vitro; The temporal and spatial expression patterns, as well as diurnal expression patterns of TaMYB72 under different light condition will be characterized by qRT-PCR at transcription level; The regulation of TaMYB72 on wheat heading date will be determined based on the analyzing of the transgenic wheat with over-expressing and the knock-down/out of this gene; The allelic variations of TaMYB72 and their effects on the heading date in wheat will be conducted using the wheat mini-core collections and their introgression lines. Through the above research, we hope to uncover the function and molecular mechanisms of TaMYB72 on regulation of wheat heading date, and provide new information on the genetic and molecular control of flowering. And ultimately provide optimum candidate gene for wheat breeding.

适宜的抽穗期是保证作物高产稳产的重要农艺性状，因此小麦抽穗期调控基因的挖掘与功能解析具有重要的科学意义和应用价值。在前期工作中，我们利用小麦转录因子大规模转化水稻的平台，鉴定出一批与抽穗期相关的转录因子基因，其中过表达TaMYB72可以使转基因水稻抽穗提前12-15天。本项目拟对TaMYB72在小麦中调控抽穗期的功能进行深入研究，包括蛋白转录激活活性及体外与DNA顺式元件结合活性检测；从转录水平分析TaMYB72基因时空表达特性及不同光照条件下的节律和周期性表达模式；通过对过表达及基因沉默的转基因小麦表型分析，明确TaMYB72对小麦抽穗期的调控作用；利用小麦微核心种质及其导入系群体，通过关联分析及连锁分析的方法研究 TaMYB72基因多样性，挖掘其优异等位基因。通过以上研究以期阐明TaMYB72对小麦抽穗期的调控作用，丰富小麦抽穗期调控的理论，并为小麦新品种的培育提供优异基因资源。

适宜的抽穗期是保证作物高产稳产的重要农艺性状，因此小麦抽穗期调控基因的挖掘与功能解析具有重要的科学意义和应用价值。在前期工作中，我们利用小麦转录因子大规模转化水稻的平台，获得了一万余株超表达小麦转录因子基因的转基因水稻植株，并鉴定出一批与抽穗期相关的转录因子基因，其中超表达TaMYB72使转基因水稻抽穗提前~12天。TaMYB72在结构上包括6个外显子和5个内含子，编码一个包含354个氨基酸残基的MYB-related转录因子。TaMYB72定位于细胞核中，在酵母中具有转录激活活性。TaMYB72在六倍体小麦基因组中具有3个拷贝，分别定为于小麦第六同源群的6A、6B和6D染色体的短臂上。在长日照条件下，TaMYB72呈现节律性表达模式，在短日照条件下，其表达不具有节律性。通过对水稻中已知的抽穗期相关基因在转基因水稻中的表达模式进行分析表明：TaMYB72可能通过某种由Ehd1介导的未知途径，调控成花素基因Hd3a和RFT1的表达，并最终促进转基因水稻提前抽穗。本研究为解析小麦抽穗期调控机制、培育小麦广适品种提供了理基础和候选基因。