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.





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