MADS-box基因家族成员在水稻花序结构（穗型）发育遗传调控网络中的功能和机理解析

Florescence architecture is a key agronomic trait. The spikelet meristem is unique to all of the Poaceae, representing the basic unit of the grass inflorescence architecture, which is crucial in establishing the yield potential of the crop. Based on genetic analyses of floral homeotic mutants in Arabidopsis thaliana, class A and class E MADS-box genes were proposed to plays crucial roles in inflorescence development by regulating floral meristem determinacy. Once activated by LFY, AP1 subsequently activates SEP3. LFY/SEP3 then activates AG, AP3 and PI. This constitutes a feed-forward loop to temporally delay ABCE gene activation, resulting in premature differentiation of floral organs and precocious termination of floral merisems. However, such the defined regulatory network underlying the spikelet meristem and floret development in rice requires to be explored. Although the basic genetic framework underlying meristem maintenance and floral organ development (ABCDE model) is conserved between Arabidopsis and rice, duplications of gene family members have produced functional diversification with respect to inflorescence architecture and floral development. In this study, we will take full advantage of what we have achieved about the rice class A and class E genes to explore the genetic interactions and the up-/down-stream targets of these spikelet meristem-related genes using combined techniques such as forward genetics, reverse genetics, functional genomics, and physiological and biochemical analysis etc. This study aims for better understanding the regulatory networks and protein-protein interactions underpinning spikelet meritem identity and differentiation in rice.

花序分生组织形态（简称穗型）是一个重要的农艺性状。小穗分生组织是禾本科植物特有的结构，直接影响穗型形态，是控制禾本科作物产量的关键因素之一。A类和E类MADS-box基因在模式植物拟南芥花分生组织特性决定上的功能研究较为清楚，形成相互调控互作关系，发挥关键作用。但是水稻花序结构（穗型）和拟南芥花序结构差异很大，分子作用模式可能更为复杂。A、E类基因在水稻花序形态建成的功能作用和调控网络亟待完善。本申请项目利用我们已有的这两类基因的水稻突变体材料，在我们对这两类基因研究的基础上，通过采用正向和反向遗传学相结合的手段、功能基因组学的研究技术和生理生化分析技术，进一步明确这些基因的遗传相互作用，并鉴定出与这些基因互作的上下游基因，以期阐明穗发育的遗传调控机制，建立遗传网络调控模型。

花序分生组织形态（简称穗型）是一个重要的农艺性状。A类和E类MADS-box基因在模式植物拟南芥花分生组织特性决定上的功能研究较为清楚，形成相互调控互作关系，发挥关键作用。然而，在水稻花序结构（穗型）发育中这两类基因的分子作用模式还相对研究较少。在本项目的资助下，我们通过采用正向和反向遗传学相结合的手段、功能基因组学的研究技术和生理生化分析技术，明确了水稻中A和E类MADS-box基因的功能和遗传相互作用，阐明了这些基因在花序分生组织中的作用机理及其在水稻生殖过程中的遗传调控功能。