植物叶片是光合作用的主要器官。很多因素包括内源信号和外界环境都影响叶片的最终形状和大小。植物叶片的发育调控机制到目前仍不十分清楚。通过DELLA蛋白RGA作为诱饵筛选本实验室的拟南芥转录因子库，从中筛选到一个新的RGA相互作用的蛋白DIT1(DELLA Interacting Transcription factor 1). 通过BiFC进一步证明RGA和DIT1确实在体内相互作用。DIT1定位在核中。过量表达DIT1导致叶片严重变形且变小。初步研究表明该基因在叶中表达。说明DIT1在植物叶片发育中起到关键的调控作用。本研究将调查DIT1过量表达和功能失活后造成叶片缺陷的详细表型，研究该基因在叶片中的表达模式，进一步验证DIT1与RGA相互作用，包括寻找它们相互作用的蛋白区域，同时将寻找转录因子DIT1的直接调控的下游基因，最终阐明DIT1调控叶片发育的分子机制。

Leaves are the major organs for photosynthesis. Many factors including endogenous signals such as various hormones and environmental cues such as fertilizer and water all affect leaf final sizes and shapes. The regulation of leaf development is rather complicated. Up to now, the mechanisms controlling leaf growth and development are still elusive. Here, we found a novel transcription factor DIT1 (DELLA Interacting Transcription factor 1) which interact with the known DELLA transcription repressor RGA though screening our Gal4-AD transcription factor library for DELLA interactors. BiFC confirmed the interaction between DIT1 and RGA. Overexpression of DIT1 led to severe leaf defects including small sizes and shape abnormalities, suggesting that DIT1 plays key roles in leaf development. This study will demonstrate the mechanisms by which DIT1 regulate leaf development by genetic and molecular approaches. The detailed phenotypes of leaves caused by overexpression or disruption of DIT1 will be investigated. The expression pattern of DIT1 in leaves will be examined. We will confirm the interaction between DIT1 and RGA and find the interaction domains in these two proteins. The downstream genes directly regulated by DIT1 will be found out to illustrate the molecular mechanisms by which DIT1 modulate leaf development.