Identification and Mapping of a New Soybean Male-Sterile Gene, mst-M

The use of sterility is common in plants and multiple loci for hybrid sterility have been identified in crops such as rice. In soybean, fine-mapping and research on the molecular mechanism of male sterility is limited. Here, we identified a male-sterile soybean line, which produces larger, abnormal pollen grains that stain poorly with I₂-KI. In an inheritance test, all F ₁ plants were fertile and the F ₂ and F _2:3 populations conformed with the expected segregation ratio of 3:1 (fertility:sterility) (p = 0.82) and showed a 1:2:0 ratio of homozygous fertile: heterozygous fertile: homozygous sterile genotypes (p = 0.73), suggesting that the sterility was controlled by a single recessive gene (designated "mst-M"). Bulked segregant analysis showed that almost all single-nucleotide polymorphisms (SNPs; 95.92%) were distributed on chromosome 13 and 868 SNPs (95.81%) were distributed in the physical region of Chromosome 13.21877872 to Chromosome 13.22862641. Genetic mapping revealed that mst-M was flanked by W1 and dCAPS-1 with genetic distances of 0.6 and 1.8 cM, respectively. The order of the consensus markers and known sterility genes was: Satt146 - (5.0 cM) - st5 - (2.5 cM) - Satt030 - (15.3 cM) - ms6 - (5.0 cM) - Satt149 - (39.5 cM) - W1 - (0.6 cM) - mst-M - (14.1 cM) - Satt516 (7.5 cM) - ms1 - (16.3 cM) - Satt595. These results suggest that mst-M is a newly identified male-sterility gene, which represents an alternative genetic resource for developing a hybrid seed production system for soybean.