水稻白穗突变体wp8的表型鉴定及候选基因定位和功能分析  

Phenotypic identification,candidate gene mapping and functional analysis of white panicle 8(wp8)mutant in rice

作　　者：刘林 朱泽 王致远 刘世家[1] 田云录[1] 周时荣 江玲[1] 刘玲珑 万建民 LIU Lin;ZHU Ze;WANG Zhiyuan;LIU Shijia;TIAN Yunlu;ZHOU Shirong;JIANG Ling;LIU Linglong;WAN Jianmin(State Key Laboratory of Crop Genetics and Germplasm Enhancement/Research Center of Jiangsu Plant Gene Engineering,Nanjing Agricultural University,Nanjing 210095,China)

机构地区：[1]南京农业大学作物遗传与种质创新国家重点实验室/江苏省植物基因工程技术研究中心,江苏南京210095

出　　处：《南京农业大学学报》2021年第6期1035-1045,共11页Journal of Nanjing Agricultural University

基　　金：江苏省农业重大新品种创制项目(PZCZ201701);国家重点研发计划项目(2016YFD0100101)。

摘　　要：[目的]叶色突变体是研究植物光合作用和光形态建成等途径的优良材料,它作为一种可利用的种质资源可应用于杂交制种中。本文旨在阐明叶绿体发育的分子机制。[方法]水稻白穗突变体white panicle 8(wp8)来自粳稻品种‘宁粳6号’化学诱变突变体库。wp8与籼稻品种‘N22’杂交构建F2分离群体用于WP8基因的遗传分析和图位克隆。[结果]相比于野生型,wp8在营养生长期叶片表现出白条纹症状并持续整个生长周期;wp8在抽穗期颖壳白色,在籽粒成熟时颖壳转为黄色。与野生型相比,wp8幼叶、穗部、成熟期剑叶光合色素含量均显著下降。用透射电镜观察幼苗期和成熟期叶片,发现wp8大部分叶绿体发生降解,一些仅存的叶绿体中类囊体片层结构消失并出现大量嗜锇体和空泡状结构。遗传分析和基因定位发现,wp8突变性状由一个隐性核基因LOC_Os06g14620突变导致,WP8为ST1(STRIPE1)的一个新等位基因。荧光定量RT-PCR分析表明,突变体活性氧、光合作用相关基因表达都发生紊乱。[结论]水稻叶色突变体wp8的白条纹叶和白穗性状是由6号染色体编码核糖核苷二磷酸还原酶小亚基基因突变导致。WP8基因不同位点变异会对水稻表型产生不同影响,通过对WP8基因功能分析,有助于阐明叶绿体发育的分子机制。[Objectives]Leaf color mutants are excellent materials for studying the photosynthesis and photomorphogenesis of plants.It can be used as an available germplasm resource and it is helpful in hybrid breeding as a marker for removing off-types.The paper aimed to elucidate the molecular mechanism of chloroplast development.[Methods]A rice white panicle 8(wp8)mutant was isolated in the chemical mutagen bank of the japonica variety‘Ningjing 6’.Genetic analysis and map-based cloning of wp8 were performed on an F2 population constructed by wp8 and the indica rice‘N22’hybridization.[Results]Compared with the wild type,the wp8 mutant showed white stripes in the leaves during the vegetative growth period and lasted throughout the following growth stages;the wp8 mutant showed white hulls at the heading stage,but turned yellow when the grains were mature.Compared with the wild type,the contents of photosynthetic pigment in the young leaves,panicle and mature flag leaf of wp8 mutant all significantly reduced.The transmission electron microscope observation of the leaves of the wp8 mutant at the seedling stage and mature stage revealed that most of the chloroplasts of the wp8 mutant were degraded,and the grana lamella in the remaining chloroplasts disappeared while a large number of osmophiles and vacuolar structures emerged.Through genetic analysis and gene mapping,it was found that the wp8 mutation trait was caused by a recessive nuclear gene LOC_Os06g14620 mutation.WP8 was a new allelic gene of ST1(STRIPE1).Quantitative RT-PCR analysis showed that the expression of reactive oxygen species related genes and photosynthetic related genes were both disordered.[Conclusions]The white stripe and white panicle traits of wp8 were caused by the gene mutation on chromosome 6 that encoded a small subunit of ribonucleoside diphosphate reductase.Variations at different sites of WP8 gene had different effects on rice phenotype.The analysis of WP8 gene function will help elucidate the molecular mechanism of chloroplast development.

关 键 词：水稻 白穗突变体 基因定位 变异分析 表达分析 

分 类 号：S511.032[农业科学—作物学]