Targeted mutagenesis using programmable DNA endonucleases, such as CRISPR
and TALENs, is promising in studying gene function in plants and in
improving crop yields. Recently, a method that eliminates the need to
emasculate the female inbred during hybrid seed production has been
described. The system relies on identifying genes critical to anther and
pollen development, such as the P450 fertility gene in maize, known as Ms26.
However, theP450 gene has not been isolated in other monocots.

The team led by A. Mark Cigan from DuPont Pioneer designed and used a homing
endonuclease, Ems26+, to generate in planta mutations in rice, sorghum and
wheat orthologs of maize Ms26. Just like in maize, mutations in Ms26
ortholog genes in rice and sorghum prevent pollen formation, resulting in
male sterile plants. However, allohexaploid wheat plants that have similar
P450 gene mutations in only one of its three genomes were still male
fertile.

Targeted mutagenesis and subsequent characterization of male fertility genes
in sorghum and wheat could be an important step in improving yields through
hybrid seed technology.



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