Co-suppression of Si401, a maize pollen specific Zm401 homologous gene, results in aberrant anther development in foxtail millet

We previously reported that the maize pollen-specific gene Zm401 functions in anther development. In this study, a Zm401's ortholog Si401 was amplified and cloned from foxtail millet (Setaria italica). Zm401 and Si401 are highly conserved with 99% of their coding sequences identical to each other. Southern blot and RT-PCR analysis reveal that Si401 has only one copy in the genome and is expressed exclusively in the panicle. Co-suppression of Si401 in foxtail millet results in multiple abnormalities during the late stages of anther development, including premature degeneration of the tapetum, pre-deposition of fibrous bands in endothecium cells, and aborted pollen grains. Our results demonstrate that Si401 plays an essential role in anther development in foxtail millet and might be useful for generation of male-sterile plants in cereal crops.