水稻是最重要的粮食作物之一，在粮食生产和消费中占有极其重要的地位。工业化的高速推进致使臭氧层不断变薄，到达地面的紫外辐射增强。研究显示，增强5%的UV-B将使水稻减产20%以上以及稻米品质将显著下降。因此，重视臭氧层变薄带来的各种生物学效应，揭示紫外线影响水稻叶片早衰的遗传分子机理，培育耐(抗)紫外线新材料,对于提高水稻产量，保障水稻生产的可持续发展及粮食安全具有重要意义。在前期的研究中，申请人以辐射诱变获得的ups早衰突变体为材料，已经将该隐性基因精细定位在第3染色体长臂上，测序分析表明在一个细胞色素P450基因的血红蛋白结合区发生了单碱基缺失，致使该基因功能丧失。本研究将在克隆该候选基因的基础上，分析其表达模式，弄清基本分子生理特征，阐明紫外线引起叶片衰老的遗传机制。此外，利用基因芯片技术、转录组高通量测序技术并结合酵母双杂，获得与该基因互作的关键基因并进行功能研究，确定其调控网络。

Rice is one of the world's most important food crops because it is a staple food for more than half of the world's population. Deletion of stratospheric ozone due to anthropogenic sources such as chlorofluorocarbons has lead to an increase in solar ultraviolet-B radiation (315-280 nm) reaching the Earth's surface, which has potentially deleterious consequences for agricultural production and natural ecosystems. Increased UV-B radiation causes significant direct and indirect biological effects including degradation and conformational changes in DNA, protein and lipids and alterations in photosynthesis, growth and morphology of plants. Studies indicated that increased UV-B radiation caused a significant reduction in dry matter and 20% yield, and affected seed quality as follows: protein, sugar and starch levels decreased in rice. So it is very important to develop UV-B-resistant rice and demonstrate the mechanisms of UV-B resistance in rice..Our previous studies showed that the ups mutant had recessive inheritance and was governed by a single locus. The ups gene determined to be on the long arm of chromosome 3 and is 0.1 cM and 0.2 cM away, respectively from the closest InDel markers ID15 and ID 19, and co-segregated with the SSLP marker RM3646. Further analysis revealed that this 90-kb sequence contains 12 putative genes including two cytochrome P450 genes. Considering that cytochrome P450s are ubiquitous heme proteins and known to play an important role in detoxification of natural and involve in biosynthesis of secondary metabolites such as flavonoid which is very important compounds for UV-B protectants in plants. We therefore considered those two cytochrome P450 genes as the primary candidates for the wild Ups gene.To address which of the two candidate genes corresponds to the ups locus present in the mutant, we compared the sequences of the two genes based on PCR products mplified from the mutant and the respective wild-type progenitors 93-11. Comparing ups to 93-11, it was observed that among the two genes, only one gene from ups mutant a single-base deletion of T in its coding sequence..In this study, we will clone the candidate gene and investigate its function and expression analysis, and reveal the molecular and physiological mechanism, and develop the UV-B resistance rice in the future. Furthermore, we also investigate its regulated network through yeast two-hybrid, microarray and widespread RNA Sequence