GmFT2a和GmFT5a差异性调控大豆结荚习性的分子机制研究

Stem growth habit is one of the most important factors that direct impact on soybean yield of single plant. Comparing with WT plants, GmFT5a-overexpressing (ox) plants terminated stem growth immediately after flowering, with reduced node numbers and plant height. while the stem of GmFT2a-overexpressing (ox) plants continued to grow after flowering, with no significant changes in node numbers and plant height, the single plant yield of GmFT5a-ox is much less than that of GmFT2a-ox, indicating that GmFT2a and GmFT5a differentially regulate soybean stem growth, however, the molecular mechanism is unclear. The yeast two-hybrid will be used to screen the proteins interact specifically with GmFT2a and GmFT5a, RNA-seq expression profiles analysis will be chose to identify the genes which are downstream of and controlled by GmFT2a and GmFT5a, CRISPR/Cas9, ChIP-PCR and other molecular technology will be performed to validate the regulatory relationship of GmFT2a, GmFT5a and their interaction proteins with soybean stem growth gene Dt1, the molecular mechanism of GmFT2a and GmFT5a differentially regulate soybean stem growth and single plant yield will be clarified.

结荚习性是直接影响大豆单株产量的重要因素之一。前期研究发现，在长日照条件下，过表达GmFT5a植株在开花后立即结束顶端生长，与野生型相比主茎节数减少并且株高变矮；而GmFT2a过表达植株在开花后继续营养生长，与野生型相比主茎节数和株高没有明显差异，而且GmFT5a过表达植株单株产量显著低于GmFT2a转基因植株；表明GmFT2a和GmFT5a差异性调控大豆花后结荚习性和单株产量，但是其分子机制尚未明确。因此，本研究拟利用酵母双杂交技术筛选分别与GmFT2a和GmFT5a互作的特异蛋白、RNA-seq表达谱鉴定GmFT2a和GmFT5a下游不同的调控基因、CRISPR/Cas9及ChIP-PCR等分子生物学手段证明GmFT2a和GmFT5a及其互作蛋白与结荚习性控制基因Dt1的调控关系，阐明GmFT2a和GmFT5a差异性调控大豆结荚习性和和单株产量的分子机制。

FLOWERING LOCUS T (FT)基因家族整合外部及内部信号调控植物的不同生长发育过程。在大豆中，FT2a和FT5a在成花诱导中起重要作用，但它们在开花后生殖生长发育的作用是未知的。异源过表达分析显示FT2a和FT5a都能诱导开花，但FT5a在开花后调控大豆结荚习性的作用显著强于FT2a。在过表达FT5a植株早期发育的生长点中，FT5a抑制拟南芥TERMINAL FLOWER1同源基因Dt1的表达，同时强烈促进APETALA1同源基因的表达。Dt1抑制因子Dt2在FT2a和FT5a过表达转基因植株生长点均上调表达，表明Dt2不参与FT5a调控大豆顶端生长过程。结合以前的FT2a和FT5a互作FDL19的研究，拟南芥bZIP转录因子FD同源蛋白FDL12与FT2a和FT5a互作，但是FDL06只特异性结合FT5a。我们的研究结果表明了FT2a和FT5a差异性调控大豆开花后的结荚习性。FDL06与FT5a的特异性互作可能在大豆开花后的有限结荚习性出现过程中起重要的作用。