Ectopic expression of a maize pollen specific gene, zm401, results in aberrant anther development in tobacco

Our previous study shows that the maize zm401 cDNA is specifically expressed in maize pollens. This evidence suggests that zm401 likely functions in pollen growth and/or development. To confirm its possible involvement in pollen development, the full length cDNA of zm40l was ectopically expressed in tobacco plants under the control of a pollen specific promoter ZM13 (from maize). RT-PCR amplification demonstrated that the ZM13-driven zm401 gene was spatially expressed in tobacco pollens. It was found that all transgenic tobacco plants expressing zm401 showed various levels of sterility, ranging from abortive flower development to male sterility. Further analyses on anther development of transgenic plants indicated multiple abnormalities in the late stages of anther development. These abnormalities include lagged degradation of the tapetum and connective tissue, failed deposition of fibrous bands in endothecium cells, and aborted pollen grain development. These results strongly suggest that zm401 plays an essential role in anther development. However the exact functions of zm401 is still unclear, and further analysis of zm401 is required to determine the exact mechanism involved in anther development.