【摘要】 脱落酸(abscisci acid ABA)作为一种重要的植物激素,在植物生长发育过程中具有很重要的作用.9-顺式-环氧类胡萝卜素双加氧酶(NCED)是ABA合成的关键限速酶,但有关NCED的生物功能报道较少.本研究发现OsNCED3具有水稻老叶中表达量最高的特性,响应非生物胁迫,外源施加ABA激素,OsNCED3基因的表达量显著下调.通过培养筛选出的纯合osnced3突变体株系,发现其较野生型有明显延缓水稻叶片衰老的表型,电导率和DAB、NBT染色,叶绿素含量也反映同样的趋势.参与叶片衰老的相关基因在osnced3突变体株系中的表达量也明显降低.营养生长期,与野生型相比,osnced3突变体株高变高.同时,在成熟期osnced3突变体株系的农艺性状如种子饱满度、千粒重、结实率都优于野生型株系.因此,推测在osnced3突变体中,OsNCED3基因受损,从而延缓水稻叶片的衰老,最终影响水稻产量.更多还原

【Abstract】 Abscisci acid(ABA)is an important phytohormone,which played a crucial role in plant development.9-cis-epoxycarotenoid dioxygenase(NCED)is a rate limited enzyme responsible for the ABA biosynthesis in plants,but the biological function of NCED is unclear.In this study,we found that OsNCED3 has the highest expression level in rice old leaves and was in response to abiotic stress.OsNCED3 was significantly down-regulated by ABA treatment.We cultivated the osnced3 mutant lines and found that it showed significantly delayed leaf senescence phenotype compared with the wild type.Moreover,the results of Ion leakage,DAB staining,NBT staining and chlorophyll content also confirmed this trait.The expression of senescence-related genes was significantly downregulated.intheosnced3 mutant lines.The height of the osnced3 mutant lines was significantly higher at the vegetative stages.Meanwhile,agronomic characters such as the fullness of seed,the mass of 1000 grains,filling rate are better than the wild type in the mature period.Taken together,these data indicate that the osnced3 mutant lines,in which the OsNCED3 gene is impaired,delay the senescence of rice leaf,and finally affect rice yield.更多还原