背景回顾：The endosperm provides nutrients and growth regulators to the embryo during seed development. LEAFY COTYLEDON1 (LEC1) has long been known to be essential for embryo maturation. 

提出问题：LEC1 is expressed in both the embryo and the endosperm; however, the functional relevance of the endosperm-expressed LEC1 for seed development is unclear. 

主要发现：Here, we provide genetic and transgenic evidence demonstrating that endosperm-expressed LEC1 is necessary and sufficient for embryo maturation. 

结果1-胚乳LEC1可以促进胚胎成熟：We show that endosperm-synthesized LEC1 is capable of orchestrating full seed maturation in the absence of embryo-expressed LEC1. 

结果2-没有胚乳LEC1，胚胎发育终止：Inversely, without LEC1 expression in the endosperm, embryo development arrests even in the presence of functional LEC1 alleles in the embryo. 

结果3-胚乳LEC1作用时期和方式：We further reveal that LEC1 expression in the endosperm begins at the zygote stage and the LEC1 protein is then trafficked to the embryo to activate processes of seed maturation. 

结论：Our findings thus establish a key role for endosperm in regulating embryo development.

 摘 要 

种子发育过程中，胚乳为胚胎的发育提供了营养和生长调节因子。LEC1一直被认为是胚胎成熟必不可少的蛋白。LEC1同时在胚胎和胚乳中表达，但是胚乳中LEC1的表达对于胚胎发育的作用还不清楚。本文中，作者通过遗传学和转基因方法，发现胚乳表达的LEC1对于胚胎的成熟是必要且充分的。作者发现，胚乳合成的LEC1能够在没有胚表达LEC1的情况下，协调种子的完全成熟。相反，如果胚乳中没有LEC1的表达，即使胚胎中存在功能性LEC1等位基因，胚胎发育也会停止。作者进一步发现，LEC1在胚乳中的表达起始于合子阶段，然后LEC1蛋白被运输到胚胎中以激活种子成熟过程。因此，本文的研究确立了胚乳在调节胚胎发育中的关键作用。