中国水稻科学2025，Vol.39Issue(6)：813-824,12.DOI:10.16819/j.1001-7216.2025.241003
水稻长护颖小粒突变体lsg8的表型鉴定与基因克隆
Identification and Gene Cloning of a Long Sterile Lemma and Small Grain Mutant lsg8 in Rice(Oryza sativa L.)
摘要
Abstract
[Objective]The aim of this study was to identify and clone a gene responsible for long sterile lemma and small grain size in rice,and to explore the genetic basis and molecular mechanism controlling these traits.[Method]A stably inherited mutant displaying long sterile lemmata and small grains was obtained from the japonica rice WYJ27 through ethyl methanesulfonate(EMS)mutagenesis.This mutant was named as lsg8(long sterile lemma and small grain on chromosome 8).The agronomic traits of both the wild-type and the mutant were observed and recorded.The epidermal cells of the glume were observed using scanning electron microscopy(SEM).An F2 segregating population was generated by crossing lsg8 with the indica rice variety IR36,and used for genetic analysis and gene mapping.Candidate genes were further identified through gene sequencing and expression analysis.RT-qPCR was performed to analyze the relative expression levels of genes regulating cell expansion and floral development.[Result]Compared with the wild type,the mutant lsg8 exhibited a significantly longer sterile lemma,significantly decreased grain width and grain thickness,and consequently a reduced 1000-grain weight.In addition,the plant height,panicle length,the length of the first,second,and fourth internodes from the top,the number of primary branches,the number of secondary branches,the number of grains per panicle,and the seed setting rate of lsg8 were significantly lower than those of the wild type WYJ27.SEM observation of the outer epidermis of the glume showed that the cell length and width of the mutant lsg8 were significantly shorter and narrower than those of the wild type.Genetic analysis suggested that the mutant phenotype is controlled by a single recessive nuclear gene.Through map-based cloning,the LSG8 gene was mapped to a region between markers M5 and M6 on chromosome 8.The physical distance between these two markers is approximately 276 kb,containing 42 open reading frames(ORFs).Sequencing analysis revealed a single nucleotide difference in ORF18(LOC_Os08g06480)between the wild type and the lsg8 mutant,indicating that ORF18 is likely the candidate gene controlling the long sterile lemma and small grain phenotype.RT-qPCR analysis revealed that LSG8 is expressed in various tissues at different developmental stages,with the highest expression in panicles at the mature stage and the lowest in leaf sheaths at the mature stage.Furthermore,significant alterations were observed in the relative expression levels of genes related to cell expansion,sterile lemma development,and floral organ identity in the lsg8 mutant.[Conclusion]The lsg8 mutant is a new allele of the previously reported ASP1 gene.The mutation in OsLSG8 results in a long sterile lemma and small grain phenotype,playing an important role in maintaining the morphogenesis of rice sterile lemma and grain morphology.关键词
水稻/长护颖/小粒/遗传分析/图位克隆Key words
rice(Oryza sativa L.)/long sterile lemma/small grain/genetic analysis/map-based cloning引用本文复制引用
陆帅,徐福祥,环海东,龚远航,张皓程,金素奎,蔡秀玲,高继平,冷语佳,陶涛,刘冉,周文玉,曹蕾,杨青青,张明秋,任鑫哲,杨芝笛..水稻长护颖小粒突变体lsg8的表型鉴定与基因克隆[J].中国水稻科学,2025,39(6):813-824,12.基金项目
国家重点研发计划资助项目(2022YFD1200103) （2022YFD1200103）
江苏省重点研发计划资助项目(BE2022336). （BE2022336）
