种子胚胎发育是植物繁殖的重要事件，决定了植物物种的延续。在农业上，胚胎发育直接关系到农作物种子安全、产量和品质的保证。赤霉素（GA）作为主要植物激素，参与了植物众多发育过程，然而其如何参与并调控胚胎发育的分子机理仍不清楚。我们前期发现：GA合成抑制剂PAC处理的拟南芥幼角果出现类似lec1突变体的表型，如胚胎畸形、种子不耐脱水干燥等，该表型能被同时处理GA所恢复；当GA信号抑制因子DELLA蛋白RGA在种子发育阶段诱导积累时，也会引起类似胚胎发育异常；进一步研究发现DELLA蛋白与胚胎发育关键因子LEC1存在互作。据此我们推测GA在胚胎发育中可能通过介导LEC1蛋白活性来发挥重要作用。在此基础上，本项目拟通过对GA在胚胎发育中的功能研究，阐明DELLAs与LEC1蛋白互作对下游基因的转录调控模式，以揭示GA参与植物胚胎发育的分子调控机制，为促进农作物保种及产量与品质的提升提供理论依据。

Embryonic development is an indispensable event for plant reproduction, which determines survival and species continuation of plants. In agriculture, the embryonic development is tightly relevant to the seeds safety, yield and quality of the crops. Gibberellin (GA) is a crucial phytohormone which mediates the multiple developmental processes in plants. However, the underlying molecular mechanism how GA mediates plant embryonic development still remains obscure. We previously found that: when treated with the GA biosynthesis inhibitor paclobutrazol (PAC), the young seeds finally present an abnormal phenotype that is similar to lec1 mutant, including embryo defect and desiccation intolerance, which could be totally suppressed if we treat with GA plus PAC instead of PAC alone; Moreover, the induction of DELLA protein RGA, a key GA signaling repressor, during embryonic developmental process, also causes a similar abnormal phenotype of embryo; We further found that DELLAs interact with LEC1, a central regulator of embryogenesis, in vivo and in vitro. Hence, we hypothesize that GA may play a vital role in embryonic development via mediating the activity of LEC1. Here, we mainly focus on the functional analysis of GA in plant embryogenesis and clarification of the molecular mechanism in which DELLA proteins and LEC1 interact to regulate downstream genes transcription. These results will shed lights on GA signal regulation in embryogenesis and provide technologic basis for promoting seeds safety, and yield and quality of the crops.