Genetic male sterility has been studied for its biological significance and commercial use in hybrid seed production. Although many male-sterile mutants have been identified in maize(Zea mays L.), most genes that cause male sterility are unknown. The team of Ke Xie from the University of Science and Technology Beijing in China reports a maize mutant, male sterility33(ms33), which has small, pale yellow anthers, and complete male sterility.
Researchers identified that the mutation in the maize GRMZM2G070304 gene was responsible for the mutant. Using CRISPR-Cas9, the team knocked out the GRMZM2G070304 gene. The resulting gene-edited lines had similar traits as the ms33 mutant, confirming GRMZM2G070304 to be the gene responsible for the mutant.
The gene was found to encode a sn–۲glycerol-3-phosphate acyltransferase (GPAT) in maize. Expression of the gene was also revealed to rescue the male-sterile phenotype of the male-sterile ms33 mutant. The gene, denoted as ZmMs33, was found to be expressed in immature anthers and root tissues.
The study reveals that the monocot-specific GPAT3 protein plays an important role in male fertility in maize. This gene may be of great value in maize male-sterile line breeding and hybrid seed production.
For more information on the study, read the article in Theoretical and Applied Genetics.