Abstract
A novel male-sterile mutant of Arabidopsis thaliana was isolated by means of T-DNA tagging. Pollen abortion of the mutant was evident after microspore release and resulted in complete disappearance of pollen grains at anthesis. A transmission electron microscope analysis revealed that primexine formation was significantly reduced and that sporopollenin was not deposited onto the microspore plasma membrane. The sporopollenin that failed to deposit aggregated and accumulated within the locule and on the locule wall. Finally, no exine formation was observed, thus, the mutant was named nef1(no exine formatioin 1). Cloning of the full-length nef1 gene indicated that the gene encodes a novel plant protein with limited sequence similarities to membrane proteins or transporter-like proteins. Expression analysis revealed that the nef1 gene was strongly expressed in flower-buds, and weakly in leaf tissues. A considerable role of the NEF1 protein is discussed.
