绒毡层的程序化死亡对于水稻雄配子发育极为重要，绒毡层的异常往往会导致雄性不育。我们在水稻EMS突变体库中获得了一个完全雄性不育突变体pdt1，经多年观察鉴定，确定其绒毡层提前程序化死亡。遗传分析表明pdt1受一对隐性核基因控制。图位克隆及互补验证确定PDT1编码一个半乳糖醛酸转移酶，其在穗部表达量显著高于其它器官。半乳糖醛酸转移酶是果胶形成的关键酶，果胶参与活性氧代谢进而影响绒毡层发育，但目前并没有半乳糖醛酸转移酶参与水稻育性发育的报道。本项目拟通过对PDT1基因的功能及机理研究，鉴定pdt1突变蛋白的酶活性；探明 pdt1突变性状的理化和免疫组化缺陷，确定其是否与果胶合成及活性氧代谢异常有关；确定PDT1的表达模式和蛋白定位区域；明确PDT1在转录水平和蛋白水平的调控模式，筛选及验证其互作蛋白。本研究希望能够揭示PDT1的基因功能及半乳糖醛酸转移酶参与水稻育性发育的分子机制。

The programmed cell death of tapetum is necessary for the development of male gamete in rice, and any abnormal in this process would result in male sterile. A nuclear male sterile mutant pdt1 was identified from EMS-treated Jinhui10 library. In pdt1, premature programmed cell death of tapetum was observed, which resulted in completely male sterility by years’ study. Genetic analysis showed that pdt1 mutant phenotype was controlled by a nuclear recessive gene. Map-based cloning and complementary verification confirmed that the PDT1 encoded a galacturonosyltransferase which is mainly expressed in panicles. Galacturonosyltransferase is a key enzyme in the synthesis process of pectin that participated in the development of tapetum. However, there is no report that the galacturonosyltransferase was invovled in male gamete development in rice. This research aims to study the function and molecular mechanism of PDT1. We propose to identify enzyme activity of pdt1 in vitro, to determine whether pdt1 mutant phenotype is related to the abnormity of pectin synthesis and metabolism of active oxygen by physicochemical and immunohistochemical study, to confirm expression pattern and protein subcellular localization of PDT1, to analysis the regulation pattern of PDT1 in transcription and protein levels, and to screen out the interacted proteins of PDT1. This study is expected to reveal the function of PDT1 and its molecular mechanism in rice fertility development.