作物学报2017，Vol.43Issue(1)：51-62,12.DOI:10.3724/SP.J.1006.2017.00051
水稻早衰突变体psls1的基因定位及克隆
Gene Mapping and Cloning of a Premature Leaf Senescence Mutantpsls1 in Rice
摘要
Abstract
Leaf early senescence directly reduces its photosynthetic capacity, decreasing crop yield and grain quality. It is of great importance to identify novel mutants and characterize their molecular and physiological mechanisms. In this paper, we reported gene mapping and cloning of apsls1 mutant (premature senescence leaf with spots) in rice. The mutant showed early senescence symptoms, including decreased chlorophyll content, over-accumulated H2O2, yellow-withered leaf and increased dead cell from bottom to top of plant after the 7-leaf stage. Moreover, the plant height, tiller number, panicle length, and the number of grains per panicle were significantly lower inpsls1. We observed the degradation of chloroplast, unclean thylakoid and numerous osmio-philic granules inpsls1leaves by transmission electron microscope (TEM). Genetic analysis demonstrated that the phenotype of psls1 was determined by a single recessive gene. Using genetic population derived frompsls1× IRAT129, thepsls1 locus was mapped in a 89 kb region flanked by markers ZS-3 and ZS-8 on chromosome 7, containing 12 putative open reading frames (ORFs). Sequence analysis revealed a single-base substitution occurred in the genomic sequence ofLOC_Os07g46460, which led to a 59 bp deletion in its cDNA, and therefore, predictedLOC_Os07g46460(PSLS1), encoding a ferredoxin-dependent glutamate synthase as the candidate gene. The mRNA expression level of mutatedPSLS1 decreased sharply, resulting in reduction of gluta-mate synthase activity and abnormal amino acid metabolism inpsls1. Under low nitrogen treatment, the senescence phenotype of psls1could occur as early as at the 3-leaf stage. These results indicated thatpsls1 senescence phenotype might be associated with the loss of glutamate synthase activity and the abnormal amino acid metabolism.关键词
水稻/早衰/基因定位/PSLS1基因/谷氨酸合酶(Fd-GOGAT)Key words
Rice/Leaf senescence/Gene-mapping/PSLS1 gene/Glutamate synthase (Fd-GOGAT)引用本文复制引用
黄雅敏,朱杉杉,赵志超,蒲志刚,刘天珍,罗胜,张欣..水稻早衰突变体psls1的基因定位及克隆[J].作物学报,2017,43(1):51-62,12.基金项目
本研究由国家自然科学基金项目(91535302)和国家转基因生物新品种培育重大专项(2015ZX08010-004)资助。 This study was supported by the National Natural Science Foundation of China (91535302) and the Major Project of China on New Varieties of GMO Cultivation (2015ZX08010-004) （91535302）
