摘要
[目的]淀粉约占水稻胚乳干物质总量的80%,胚乳中淀粉的组分与含量以及颗粒结构对稻米品质具有重要影响。因此,阐明水稻淀粉合成的分子机制对品质改良具有重要意义。[方法]通过60Co-γ辐照诱变粳稻品种‘中花11’(ZH11),得到1个稳定遗传的胚乳心白突变体white core(whc)。对该突变体的形态学特征、理化性质、淀粉结构等性状进行了分析,并对突变体whc和‘N22’杂交配制的F_2群体进行基因定位。[结果]与野生型相比,该突变体表现为胚乳中心粉质不透明,粒宽与有效穗数增加,千粒质量下降14.5%。whc突变体成熟种子的直链淀粉含量减少24.7%,而总蛋白含量变化不明显。胚乳横截面扫描电镜分析发现,突变体whc的粉质胚乳部位淀粉粒异常。挑选极端单株将whc精细定位在Chr 4染色体长臂的RM349和d1分子标记之间,物理距离为158 kb。测序发现whc突变体中1个编码三角状四肽重复结构域蛋白[tetratricopeptide repeat(TPR)domain containing protein]的基因发生点突变,导致蛋白翻译提前终止。qRT-PCR分析显示,whc突变体中编码AGPase各亚基以及部分淀粉合酶的相关基因表达量发生改变。[结论]水稻心白突变体whc的表型可能是由1个编码TPR蛋白结构域的基因控制。
[Objectives]Starch accounts for about 80% of the total dry matter content of rice endosperm,and composition and content of starch as well as starch granule structure in the endosperm have important influence on the rice quality.Therefore,it is important to clarify the molecular mechanism of starch synthesis in rice.[Methods]A stable white core endosperm mutant（whc） was obtained by mutagenesis of60 Co-γ in a japonica rice variety‘Zhonghua 11＇（ZH11） background.Analysis of phenotypic traits,physicochemical properties,and starch structure was carried out.Further,genetic linkage analysis was performed using an F2 population derived from whc and‘N22＇cross.[Results]Compared to the wild type,the mutant showed floury and opaque in the center of endosperm.In contrast to the increased grain width and effective panicle number,the whc had 14.5% less 1 000-grain weight than its wild type.Meanwhile,the amylose content in the mature seeds of the whc was 24.7% decreased,whereas the total protein content showed no significant difference.Scanning electron microscopy analysis of endosperm cross section showed that starch granules in the floury part of the mutant were abnormal,relative to its wild type.The extreme individual was selected and the whc locus was delimited between the RM349 and d1 molecular markers on the long arm of chromosome 4,with a physical distance of 158 kb.Sequence analysis revealed that coding region of a tetratricopeptide repeat（TPR） domain protein had a single nucleotide substitution,leading to premature termination of protein translation.Quantitative RT-PCR indicated that expression levels of genes encoding the AGPase subunits and other starch synthesisrelated enzymes in the whc mutant endosperm had changed.[Conclusions]The phenotype of the whc was likely controlled by the gene encoding a TPR domain containing protein.
作者
刘子文
胡曼曼
王致远
张瑜竣
谷晗
游佳
王益华
江玲
刘玲珑
LIU Ziwen, HU Manman, WANG Zhiyuan,ZHANG Yujun, GU Han, YOU Jia, WANG Yihua, JIANG Ling, LIU Linglong(State Key Laboratory of Crop Genetics and Germplasm Enhancement/Research Center of Jiangsu Plant Gene Engineering, Nanjing Agricultural University ,Nanjing 210095 ,Chin)
出处
《南京农业大学学报》
CAS
CSCD
北大核心
2018年第2期231-239,共9页
Journal of Nanjing Agricultural University
基金
国家重点研发项目(2016YFD0100101)
江苏省科技支撑计划项目(BE2015355-1)
江苏省农业科技自主创新资金课题(CX(16)1029)
国家自然科学基金项目(31571629)
关键词
水稻
心白突变体
淀粉
理化性质
基因定位
rice
white core （whc） mutant
starch
physicochemical properties
gene mapping
