花生双受精后合子仅分裂几次就停止发育，子房没有膨大。子房柄却不断伸长形成"果针"。当果针将位于其顶端的子房推入土壤后，在黑暗条件下胚胎和子房的发育重新启动。光信号抑制了花生胚胎和子房的发育，但其分子机理尚不清楚。 光敏色素相互作用因子（PIFs）是光信号传导途径的关键转录因子，能与赤霉素、油菜素内酯、乙烯等激素信号互作，影响植物的生长发育。本项目将在花生转录组分析的基础上克隆花生PIF家族的基因，检测花生果针入土前后荚果发育重新启动关键时期PIFs 在mRNA和蛋白水平的积累模式；验证PIFs与DELLA、EIN3、BZR1等的互作关系；研究PIF在花生中过量表达和抑制表达对赤霉素、油菜素内酯和乙烯信号以及胚胎发育关键基因的影响。通过研究光信号对激素信号及下游胚胎发育关键基因的调控，分析PIFs在花生果针入土前后荚果膨大前后对下游基因的调控，阐明光信号抑制花生荚果发育的分子机理。

After fertilization, the zygote cell divides only few times and then the embryo and pod development is arrested in continuous sun light or regular day/night photo period. When the elongating gynophore pushes the ovary to the soil, the embryo and pod development resumes under dark condition. Light prevented embryo and pod development, however, little is known about the molecular mechanism of light-regulation on embryo and pod development. Phytochrome interacting factors (PIFs) are key components of light signaling and they link light signals to the signaling of phytohormones, such as gibberellin (GA), brassinosteroid (BR) and ethylene, in regulation of plant growth and development. In this work, we will clone the PIF family genes based on our gynophore transcriptome sequence information. The mRNA and protein accumulation of PIFs will be quantified before and after gynophore soil penetration, before and at the beginning of pod enlargement. The proteins interaction mode between PIFs and DELLA, BZR1 and EIN3 will be studied. The effects of over expression and RNAi of PIFs on phytohormone signals of GA, BR and ethylene and key genes of embryo development will be determined in transgenic peanut. This work will elucidate the role of PIFs on peanut pod development and provide experimental data for understanding the molecular mechanism of light inhibition of peanut pod development.