水稻早衰突变体psls1的基因定位及克隆

发布时间：2018-11-15 11:39

【摘要】：水稻叶片早衰直接影响作物的光合效率,减少产量,降低品质。深入研究早衰的分子机制对控制和延缓衰老具有重要意义。本文报道了一个早衰突变体psls1(premature senescence leaf with spots)的基因定位及克隆结果。突变体在发育到七叶期以后,叶片自下而上叶绿素含量下降,过氧化氢过量积累,突变体叶片逐渐黄化至枯萎;其他农艺性状如株高、分蘖数、主穗长、结实率和穗粒数也相应变差。电镜观察进一步发现,psls1衰老叶片中叶绿体降解、类囊体基粒片层模糊,嗜锇颗粒明显增多。遗传分析表明,psls1受1对隐性基因控制,利用psls1×IRAT129杂交组合F2分离群体中的1690个早衰个体,将基因PSLS1定位在第7染色体分子标记ZS-3和ZS-8之间89 kb的范围内。测序研究发现,区间内一个编码铁氧还依赖的谷氨酸合酶基因LOC_Os07g46460的第2外显子末位的G被替换为A,导致转录本的错误剪切,突变体的c DNA缺失了57 bp碱基片段。在突变体中该基因表达量下降,谷氨酸合酶活性降低,其产物谷氨酸含量显著下降、其他氨基酸代谢紊乱。水培低氮处理下可诱发突变体psls1早衰。研究结果表明,由于PSLS1突变使得谷氨酸合酶失活,氮代谢异常而导致突变体psls1早衰。
[Abstract]:Premature senescence of rice leaves directly affects the photosynthetic efficiency of crops, reducing yield and quality. It is very important to study the molecular mechanism of premature senescence to control and delay senescence. In this paper, the gene location and cloning results of a premature aging mutant psls1 (premature senescence leaf with spots) were reported. The chlorophyll content of the mutant decreased from the bottom to the top of the leaf, the content of hydrogen peroxide was excessive, and the leaf of the mutant was gradually yellowed to wilt. Other agronomic traits, such as plant height, tiller number, main ear length, seed setting rate and grain number per panicle, also became worse. It was further observed by electron microscope that chloroplast degradation, thylakoid granulocyte lamellar blur and osmiophilic granules increased significantly in psls1 senescent leaves. Genetic analysis showed that psls1 was controlled by a pair of recessive genes. Using 1690 premature senility individuals in F _ 2 segregated population of psls1 脳 IRAT129 hybrid, the gene PSLS1 was located within the range of 89 kb between ZS-3 and ZS-8 on chromosome 7. Sequencing results showed that G at the end of exon 2 of a ferric-dependent glutamate synthase gene (LOC_Os07g46460) was replaced by A in the region, resulting in miscut of transcripts, and the deletion of 57 bp base fragment in c DNA of the mutants. In the mutant, the expression of the gene decreased, the activity of glutamate synthase decreased, the content of glutamate decreased significantly, and the metabolism of other amino acids was disturbed. The mutant psls1 premature senescence could be induced by low nitrogen treatment under hydroponic culture. The results showed that PSLS1 mutation resulted in inactivation of glutamate synthase and abnormal nitrogen metabolism, which resulted in premature failure of mutant psls1.
【作者单位】：中国农业科学院作物科学研究所/农作物基因资源与基因改良国家重大科学工程;四川省农业科学院生物技术核技术研究所;
【基金】：国家自然科学基金项目(91535302) 国家转基因生物新品种培育重大专项(2015ZX08010-004)资助~~
【分类号】：S511

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