Epigenetics of Plant Developmental Transitions - Repressors of the Embryonic Program

种子是植物农业中最重要的经济终端产品。种子质量的提高需要对种子发育的全面了解，特别是在种子成熟的后期，此时正在合成和积累储存储备，如蛋白质，淀粉，脂质和其他营养物质。种子贮藏蛋白（SSP）基因一直被认为是研究种子成熟的分子标记和研究组织特异性基因表达调控的模型系统。一些基因被认为是种子成熟的主要调控因子，包括SSP，但目前关于这些基因的调控及其与靶标的相互作用的知识仍然是零散的。我们已经在拟南芥（分子生物学研究的模式植物）中进行了遗传筛选，以寻找调节SSP表达的基因。在一次筛选中，我们鉴定了种子成熟基因在叶子中异位表达的突变体。这些基因的身份突变表型的基础上已被揭示：他们大多是表观遗传调节基因的表达，通过修改染色质的结构。这里提出的研究是基于我们以前的工作，并继续寻找和表征控制种子成熟程序表达的遗传和表观遗传网络。这项工作完成后，将丰富和拓宽我们对植物种子和营养体发育过程中基因表达调控的认识。由于种子成熟程序是一个进化上保守的发育程序，从模式植物拟南芥中获得的知识可以很容易地转移到双子叶作物，如油菜，大豆和菜豆，并最终有助于未来种子质量的改进。

Seeds are economicaly the most important end product in plant agriculture. The improvement of seed quality requires a thorough understanding of seed development, particularly in the later phase of seed maturation, when storage reserves such as proteins, starches, lipids and other nutrients are being synthesized and accumulated. Seed storage protein (SSP) genes have long been considered as molecular markers for the study of seed maturation and as a model system for the investigation of the control of tissue specific gene expression. A few genes are known as master regulators of seed maturation including of SSPs, but present knowledge on these genes' regulation and interaction with their targets is still fragmented. We have already performed a genetic screen in Arabidopsis (a model plant for molecular biology research) to look for genes that regulate the expression of SSPs. In one screen, we identified mutants where seed maturation genes are ectopically expressed in leaves. The identities of these genes underlying the mutant phenotypes have been revealed: they are mostly epigenetic regulators that regulate gene expression by modifying the structure of chromatin. The research proposed here is based on our previous work and continues to search for and characterize the genetic and epigenetic network that controls the expression of the seed maturation program. This work, when completed, will enrich and broaden our knowledge on gene expression regulation during plant seed and vegetative development. Since the seed maturation program is an evolutionarily conserved developmental program, the knowledge gained from the model plant Arabidopsis can easily be transferred to dicotyledonous crops, such as canola, soybean and common bean, and will ultimately contribute to seed quality improvement in the future.