Male sterility (MS) is an important tool for hybrid seed production in many crops. In maize, the development of more male sterile line resources is still highly desirable, and the availability of new genetic tools such as the CRISPR-Cas9 system provides an alternative for modifying MS genes in maize.

Scientist Yunjun Liu of the Chinese Academy of Agricultural Sciences and colleagues targeted the MS8 gene in maize for gene editing. This gene encodes a putative ß-1,3-galactosyltransferase and affects the meiotic stage in anther development. Results show MS8 gene mutations in the F1 and F2 generations but not in the T0 generation, which were revealed through DNA sequencing. Further analysis uncovered a hemizygous (only one copy, instead of two) mutation in the gene, thus explaining the segregation of the trait in the F1 and F2 generations. Nevertheless, the study proves the inheritability of the mutation in maize, demonstrating the utility of CRISPR-Cas9 in male sterile line production. These mutant lines can be hybridized to other elite lines. The researchers also addressed the need to optimize and improve their gene targeting tool for a higher genome editing efficiency.

For more information, read the research article in Frontiers in Plant Science.