中国水稻科学2017，Vol.31Issue(6)：568-579,12.DOI:10.16819/j.1001-7216.2017.7003
两个垩白突变体的鉴定及突变基因的图位克隆
Identification and Gene Mapping-based Clone of Two Chalkiness Mutants in Rice
摘要
Abstract
[Objective]Chalkiness affects the appearance, processing, cooking and eating quality of rice. The objective of the study was to uncover the genetic mechanism of two rice chalky endosperm mutants for improving rice quality.[Method]Two chalkiness mutants, eb6 and eb7 were identified from EMS-treated japonica rice Zhonghua 11. The agronomic traits and starch physicochemical properties of the two mutants were investigated. Genetic analysis and map-based cloning for the gene responsible for the eb6 and eb7 phenotypes were carried out with the F2 population derived from the cross between eb6 and Nanjing 11, eb7 and 93-11. Furthermore, the expression pattern of candidate gene and the transcript levels of genes related to starch synthase in mutants and wild type(WT) were also investigated.[Result]The central parts of them were white and opaque, with loosely and irregularly arranged and smaller compound starch granules(SGs). Whereas, the marginal part of endosperms of WT and mutants and the central part of WT were filled with densely packed, similar sized polyhedral SGs. The amylose content and gel consistency of mutants were dramatically lower than those of WT. Simultaneously, the proportions of chains with degree of polymerization(DP) of amylopectin in the range from 6 to 16 were significantly increased, whereas the proportion of chains with DP in the range from 16 to 23 was noticeably decreased in the eb6. Genetic analysis showed that a single recessive gene controls chalkiness phenotype of mutants. Based on the F2 population derived from the cross between eb6 and Nanjing 11, the gene was finally narrowed down to a 86.6 kb physical region on chromosome 1. Within this region, one open reading frame(LOC_Os01g44220) has been annotated as large subunit of ADP-glucose pyrophosphorylase gene(OsAGPL2). Sequence analysis revealed that there was only one a nucleotide substitution in the 3rd exon of eb6 and the 7th exon of eb7, which resulted in an amino acid replacement in OsAGPL2, respectively. The qRT-PCR and in-situ hybridization assay indicated that OsAGPL2 was mainly expressed in the developing grains. Moreover, the expression patterns of many genes involved starch synthesis were intensively influenced in mutants.[Conclusion]OsAGPL2 indisputably corresponds to endosperm chalkiness of eb6 and eb7. And all results suggest that OsAGPL2 plays an important role in starch synthesis, the formation of compound starch granules and rice quality.关键词
垩白/淀粉合成/图位克隆/OsAGPL2/水稻Key words
chalkiness/starch synthesis/mapping-based cloning/OsAGPL2/rice分类
生物科学引用本文复制引用
张习春,鲁菲菲,吕育松,罗荣剑,焦桂爱,邬亚文,唐绍清,胡培松,魏祥进..两个垩白突变体的鉴定及突变基因的图位克隆[J].中国水稻科学,2017,31(6):568-579,12.基金项目
国家重点研发计划资助项目(2016YFD0101801) （2016YFD0101801）
国家自然科学基金资助项目(31471472, 31301303, 31501280). （31471472, 31301303, 31501280）
