Identification and fine mapping of a glume-like lodicule mutant in rice (Oryza sativa L.).

【Objective】The identification and cloning of novel mutant genes of floral organ in rice would play an important role in understanding the molecular genetic mechanisms and molecular signal pathways regulating floral organ development. 【Method】Field identification,comparison between mutant and wild-type floral organs,statistics of segregation of different phenotypes as well as gene mapping based on map-based cloning were used to describe the characteristics of floral organ,to determinate the inheritance of gll mutant and high-resolution mapping of GLL gene.【Result】It was shown that a wide variety of spikelet developmental defects exhibited from outer to inner floral organs in gll mutant,and the main mutant phenotypes were glume-like lodicule and the extra glume.The Chi-square test of F2 and F3 individuals derived from four crosses indicated that the segregation ratio of phenotypes was consistent with the inheritance of single recessive nuclear gene.The plants with gll phenotype were obtained from F2 or F3 generations from Nipponbare×gll for mapping GLL gene.One hundred and fifty-six polymorphic molecular markers,which evenly distributed on 12 chromosomes in rice,were used to test 408 individules with mutant phenotype. According to statistical analysis,the GLL gene was located on rice chromosome 1 between RM1068 and RM3482 with a genetic distance of 4.6 and 2.3 cM to gll locus,respectively.Then,four SSR markers were developed within this region,gll locus was finally mapped on a region of 108 kb physical distance.【Conclusion】The gll mutant is controlled by a recessive nuclear gene,which is located on the long arm of chromosome1,between RM6097 and RM6827 with 108 kb physical distance.