水稻温敏雄性不育突变体mh86s的鉴定及基因克隆

Identification and Gene Cloning of the Thermo-sensitive Male Sterile Mutant mh86s in Rice

光/温敏核雄性不育基因在水稻杂种优势利用中发挥着重要作用。发掘光/温敏核雄性不育突变体及其基因有助于更好地了解水稻中光/温敏核雄性不育的机制并丰富遗传资源。本研究在籼稻材料明恢86的转基因后代中鉴定了1个雄性不育突变体,该突变体在正常生长季表现为雄性不育,花药较野生型小,淡白色,镜检无花粉,孕穗期低温处理后育性恢复,为1个温敏雄性不育突变体,命名为mh86s。利用突变体mh86s分别和其野生亲本明恢86及籼稻材料93-11杂交,构建F 2遗传群体,遗传分析表明雄性不育性状由1对隐性核基因控制。采用图位克隆技术将该温敏雄性不育基因定位在第2染色体分子标记Indel7.38和SNP3之间49.8 kb的物理区间内。在该定位区间内包含已克隆的温敏雄性不育基因tms5。测序结果表明,突变体mh86s中tms5基因和野生型相比,第2外显子1个碱基发生了替换(G-T),导致推测的161位氨基酸由甘氨酸变为缬氨酸。利用突变体mh86s和携带tms5基因的温敏不育系HD9802S杂交,F 1表现为温敏雄性不育。据此推断突变体mh86s中的温敏雄性不育基因为tms5的新等位基因,命名为tms5-mh86。研究结果丰富了tms5基因资源,有助于解析tms5基因结构与功能,相应的分子标记亦可用于tms5-mh86的标记辅助选择。

Photo-or thermo-senstive genic male sterile gene(PGMS or TGMS)has played an important role in the utilization of heterosis in rice.The identification of PGMS or TGMS mutants and genes could help to better understand the mechanism of PGMS or TGMS in rice and enrich the genetic resources.In this study,a male sterile mutant was identified from the transgenic offspring of Minghui 86,an indica rice material.The mutant showed male sterility in the normal growth season,the anthers were smaller than those of the wild type,pale white,and no pollen was detected by microscopy.The fertility could be recovered after the low-temperature treatment at booting stage,and the mutant was a thermo-sensitive male sterile mutant,which was named mh86s.The mutant mh86s was hybridized with their wild parent Minghui 86 and the indica rice material 93-11,respectively,thus to construct the F 2 genetical population.And the genetic analysis showed that the male-sterile character was controlled by a pair of recessive genic gene.By using the map-based cloning,the gene of thermo-sensitive male sterility was located in the 49.8 kb physical interval between the molecular markers Indel7.38 and SNP3 of the chromosome 2,and the cloned thermo-sensitive male sterility gene tms5 was included in the mapping interval.The sequencing analysis revealed that there was a single-base substitution(G to T)in the second exon of tms5 gene in the mutant mh86s compared to the wild type,which led the presumed amino acid was changed from glycine to valine at the 161th position.F 1 was characterized by thermo-sensitive male sterility by the hybridization of the mutant mh86s and the thermo-sensitive male sterile line HD9802S carrying tms5 gene.Therefore,it was inferred that the gene of thermo-sensitive male sterility in the mutant mh86s was the new allele of tms5,which was named tms5-mh86.The results of this study enriched the tms5 gene resources and contributed to the analysis of tms5 gene structure and function,and the corresponding molecular markers could also be used in the marker-assisted selection of tms5-mh86.