Genetic Analysis and Fine Mapping of a Spontaneously Mutated Male Sterility Gene in Brassica rapa ssp. chinensis

Male sterility has been widely used in hybrid seed production in Brassica, but not in B. rapa ssp. chinensis, and genetic models of male sterility for this subspecies are unclear. We discovered a spontaneous mutant in B. rapa ssp. chinensis. A series of progeny tests indicated that male sterility in B. rapa ssp. chinensis follows a three-allele model with BrMsa, BrMsb, and BrMsc. The male sterility locus has been mapped to chromosome A07 in BC1 and F2 populations through genotyping by sequencing. Fine mapping in a total of 1,590 F2 plants narrowed the male sterility gene BrMs to a 400 kb region, with two SNP markers only 0.3 cM from the gene. Comparative gene mapping shows that the Ms gene in B. rapa ssp. pekinensis is different from the BrMs gene of B. rapa ssp. chinensis, despite that both genes are located on chromosome A07. Interestingly, the DNA sequence orthologous to a male sterile gene in Brassica napus, BnRf, is within 400 kb of the BrMs locus. The BnRf orthologs of B. rapa ssp. chinensis were sequenced, and one KASP marker (BrMs_indel) was developed for genotyping based on a 14 bp indel at intron 4. Cosegregation of male sterility and BrMs_indel genotypes in the F2 population indicated that BnRf from B. napus and BrMs from B. rapa are likely to be orthologs. The BrMs_indel marker developed in this study will be useful in marker-assisted selection for the male sterility trait.

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Genetic analysis and molecular mapping of a nuclear recessive male sterility gene, ms91(t), in rice

Genome ◽

10.1139/g07-060 ◽

2007 ◽

Vol 50 (9) ◽

pp. 796-801 ◽

Cited By ~ 3

Author(s):

Xia Liu ◽

Songwen Wang ◽

Yong Wang ◽

Shu Wei

Keyword(s):

Male Sterility ◽

Molecular Mapping ◽

Recessive Gene ◽

Chromosome 1 ◽

Aflp Analysis ◽

Hybrid Seed Production ◽

Spontaneous Mutant ◽

Backcross Population ◽

Sterility Gene ◽

Male Sterility Gene

Mutations that result in plant male sterility provide means not only to probe reproductive development but also to facilitate commercial heterosis application and hybrid seed production. In this study, we report a novel male sterility gene, ms91(t), in a spontaneous mutant line (SH38) from a Chinese rice cultivar (Oryza sativa subsp. japonica ‘Jijing14’). The sterility of SH38 was studied by examining its progenies derived from crosses with 6 japonica cultivars. Corresponding F2 populations were obtained by selfing each of the 6 F1s and a backcross population was produced by crossing SH38 to the F1 of SH38 × C18. Our results revealed that SH38 has normal agronomic traits but produces no pollen grains. Segregations of male-sterile and male-fertile progenies in the F2 and backcross populations fit well with ratios of 3:1 and 1:1, respectively, indicating that ms91(t) is a single recessive gene. Amplified fragment length polymorphism (AFLP) analysis of SH38 and Jijing14 plants showed the presence of a unique band in SH38. Simple sequence repeat (SSR) analysis of the bulked and individual progenies of the F2 population of SH38 × C18 showed linkage of ms91(t) with the SSR marker RM5853 on chromosome 1. Subsequently, ms91(t) was fine-mapped to the interval between markers RM7075 (3.75 cM) and RM5638 (3.57 cM). Our results would facilitate the isolation of ms91(t) and male sterility in heterosis application.

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