水稻粒厚主效位点qGT8精细定位和候选基因分析  

Fine Mapping and Candidate Gene Analysis of qGT8, A Major QTL for Grain Thickness in Rice

作　　者：高方远[1] 罗正良[1] 任鄄胜[1] 吴贤婷[1] 陆贤军[1] 苏相文[1] 吕建群[1] 任光俊[1] 

机构地区：[1]四川省农业科学院作物研究所,成都610066

出　　处：《中国农业科学》2015年第24期4859-4871,共13页Scientia Agricultura Sinica

基　　金：国家"863"计划(2014AA10A603;2014AA10A604);现代农业产业技术体系(CARS-01-08);四川省青年科技创新研究团队专项计划(2011JTD0022);四川省财政创新能力提升工程(2013GXJS-005)

摘　　要：【目的】在已鉴定的稻谷粒长、粒宽和粒厚QTL的基础上,对控制粒厚的主效QTL进行精细定位和候选基因分析,以解析川106B(C-106B)细长粒形的遗传基础,为进一步通过分子技术改良其产量水平提供科学依据。【方法】以细长粒形的优质籼稻保持系川106B与籽粒较宽厚的籼稻保持系川345B(C-345B)杂交,构建包含182个单株的F_2群体,采用QTL Catographer v2.5软件基于复合区间作图法发掘与稻谷粒形性状相关的QTL;进一步从BC_3F_2群体筛选隐性单株(稻谷厚度较薄)对粒厚主效QTL(qGT8)进行精细定位,并对候选基因进行测序和荧光定量PCR分析。分别构建qGT8位点携带川106B等位基因的近等基因系(NIL-gt8^(C-106B))和携带川345B等位基因的近等基因系(NIL-GT8^(C-345B))并调查其稻米外观品质及产量性状。【结果】川106B和川345B的粒长、粒宽和粒厚表型存在显著差异。利用F_2群体检测到2个粒长QTL、3个粒宽QTL和3个粒厚QTL,其中,位于第7染色体区间RM21892—RM3589的粒长主效QTL(qGL7)可解释粒长变异的68.23%,川106B等位基因在该位点可增加粒长0.47 mm。控制稻谷粒宽和粒厚的主效QTL(qGW8和qGT8)位于第8染色体上相同区间RM6070—RM447,分别解释相应表型变异的26.48%和34.89%,增加粒宽或粒厚的等位基因均来自于川345B。利用1 732个BC_3F_2隐性单株,将粒厚主效位点qGT8精细定位在标记SG930和SG950间的11.2 kb区段,该区段仅包含1个注释基因LOC_os08g41940(OsSPL16)。对该基因测序分析发现,川106B和川345B在起始密码子ATG上游2 kb区段存在7个差异位点,在编码区有5个多态性位点,其中,川106B在第3外显子插入2 bp(c.1006_1007插入CT)引起移码突变,且位于qGT8的OsmiR156结合位点,推测为川106B籽粒厚度变薄、宽度变细的关键位点。实时荧光定量PCR分析发现,qGT8在幼穗中表达量较高,且在川106B和川345B中的表达方式相似,表达量在1—8 cm长幼穗发育时�[Objective]The paper is order to identify quantitative trait loci（QTLs） for grain length（GL）,width（GW） and thickness（GT）,and further to narrow down the genomic region containing the major QTL for GT and analyze the possible candidate genes,which would help us to understand the genetic basis underlying the formation of slender grains and facilitate the efforts to the marker-assisted improvement of yield in a cytoplasmic male-sterile（CMS） maintainer line Chuan 106B（C-106B）.[Method]In this study,C-106 B,which has a long slender grain type and good grain quality,was crossed with Chuan345B（C-345B）,another CMS maintainer line with thicker and wider grain,to produce F2 population for a preliminary QTL analysis.The chromosome interval of QTLs for grain shape was identified by composite interval mapping（CIM） using QTL Catographer v2.5.Then,a BC3F2 population derived from the same cross was developed and those plants with thinner grain were further picked out for the fine mapping of the major QTL（qGT8） for GT.Sequencing analysis and quantitative real-time PCR for the candidate gene were also conducted.In addition,a pair of nearisogenic lines（NIL） carrying the C-106B（NIL-gt8-（C-106B）） and C-345B（NIL-GT8-（C-345B）） alleles at qGT8 locus were bred and applied to survey for yield and quality traits,respectively.[Result]Significant differences were observed for GL,GW and GT between C-106 B and C-345 B.Using the phenotype and genotype data of the F2 population,two QTLs for GL,three for GW and three for GT were identified.Among these,the major QTL for GL,accounting for 68.23%of phenotypic variance was mapped to the region between RM21892 and RM3589 on chromosome 7.The allele from C-106 B was responsible for increasing GL by 0.47 mm at this locus.Two major QTLs（qGW8 and qGT8） controlled GW and GT,each explaining up to 26.48%and 34.89%of the variation,respectively,were found in the same interval of RM6070-RM447 on chromosome 8.The C-345 B alleles contributed to the increase

关 键 词：水稻 粒形 粒厚 数量性状基因座位 产量 品质 

分 类 号：S511.21[农业科学—作物学]