Map-Based Cloning, Phylogenetic, and Microsynteny Analyses of ZmMs20 Gene Regulating Male Fertility in Maize

Genic male sterility (GMS) mutant is a useful germplasm resource for both theory research and production practice. The identification and characterization of GMS genes, and assessment of male-sterility stability of GMS mutant under different genetic backgrounds in Zea may (maize) have (1) deepened our understanding of the molecular mechanisms controlling anther and pollen development, and (2) enabled the development and efficient use of many biotechnology-based male-sterility (BMS) systems for hybrid breeding. Here, we reported a complete GMS mutant (ms20), which displays abnormal anther cuticle and pollen development. Its fertility restorer gene ZmMs20 was found to be a new allele of IPE1 encoding a glucose methanol choline (GMC) oxidoreductase involved in lipid metabolism in anther. Phylogenetic and microsynteny analyses showed that ZmMs20 was conserved among gramineous species, which provide clues for creating GMS materials in other crops. Additionally, among the 17 maize cloned GMS genes, ZmMs20 was found to be similar to the expression patterns of Ms7, Ms26, Ms6021, APV1, and IG1 genes, which will give some clues for deciphering their functional relationships in regulating male fertility. Finally, two functional markers of ZmMs20/ms20 were developed and tested for creating maize ms20 male-sterility lines in 353 genetic backgrounds, and then an artificial maintainer line of ms20 GMS mutation was created by using ZmMs20 gene, ms20 mutant, and BMS system. This work will promote our understanding of functional mechanisms of male fertility and facilitate molecular breeding of ms20 male-sterility lines for hybrid seed production in maize.