中国农业科学2016，Vol.49Issue(10)：1835-1843,9.DOI:10.3864/j.issn.0578-1752.2016.10.001
水稻穗退化突变体 spd11的遗传分析及候选基因鉴定
Genetic Analysis and Candidate Gene Identification of the Panicle Degradation Mutant spd11 in Rice
摘要
Abstract
[Objective]The objective of this study was to gain a better understanding of the regulation mechanism of early rice panicle development by genetic analysis and candidate gene identification of panicle degradation mutant spd11. [Method] A panicle degradation mutant, spd11, was isolated by ethyl methanesulfonate mutagenesis from the mutant library of japonica rice dense and erect mutant dep2 of Zhonghua 11. Phenotypes and the main agronomic traits of spd11 were analyzed under field conditions in Chengdu, Sichuan. Because spd11 can not seed, we individually harvested each plant of the isolate spd11 mutant strains lines and planted each of the plants as an independent line for genetic analysis. We investigated the segregation of each strain and analyzed the genetic pattern of spd11. The mutant gene of spd11 was mapped using F2 populations by crossing spd11+/spd11-plants with Gang 46B. Then, we conducted DNA sequencing, phylogenetic and alignment analysis of LOG proteins in different species.[Result] Compared with the control, spd11 exhibited long flag leaf blade lengths. The lengths of primary branches were shortened along with a 58% decrease in branch numbers. The florets of spd11 almost degenerated to white floc, though incompletely degenerated florets consisting only of a completely closed husk could be found occasionally. Other agronomic traits such as tiller number and flag leaf blade width showed little difference across lines. Genetic analysis showed that some lines were wild-type plants, but other lines isolated mutant plants. The segregation ratios between wild-type and mutant plants were all fitted to 3:1, indicating that spd11 was controlled by a single recessive nuclear gene. Then, the mutant gene was mapped to a region of 43.2 kb between two In/Del markers ch1-2295 and ch1-2299 on the long arm of chromosome 1, and the genetic distance were 0.23 cM and 0.46 cM, respectively, containing 8 predicted genes. Sequencing analysis revealed that a single base was changed (G116A) in the coding region of the OsLOG gene which encodes a cytokinin-activating enzyme, causing a missense mutation (C39Y). Alignment and phylogenetic analysis indicated that the LOG proteins were highly conserved in different species, and the mutation in spd11 was located at a very important amino acid site. Comprehensive analysis of the mutation sites and the phenotypes of reported log allelic mutants hinted that this site (C39Y) may lie within OsLOG. [Conclusion] SPD11 may be allelic to the OsLOG gene, and the mutation on a key site of OsLOG could affect cytokinin activation in spd11 mutant, eventually leading to the panicle degradation phenotype.关键词
水稻/穗退化突变体/遗传分析/候选基因鉴定/OsLOGKey words
rice/panicle degradation mutant/genetic analysis/candidate gene identification/OsLOG引用本文复制引用
钟萍,孙昌辉,陈璞睿,王迁,肖富良,张宽,马芙蓉,黄美菱,王平荣,邓晓建..水稻穗退化突变体 spd11的遗传分析及候选基因鉴定[J].中国农业科学,2016,49(10):1835-1843,9.基金项目
国家自然科学基金（31401358，31371602）、教育部博士点基金 （）
