The Primary Fuction Research Of The Male-sterile Gene NEF1in Arabidopsis Thaliana

Nef1is a male-sterile mutant of Arabidopsis thaliana, which shows defects inexine pattern formation. In this work, we identified a allelic mutant of nef1whichwas called nef1-1due to T-DNA insertion. Sequencing analysis revealed that theT-DNA was inserted into the promoter of NEF1,135bp upstream from the start codon.Nef1-1exhibits completely male-sterile, the segregation ratio of fertile and sterileplants fits an approximate412:132(?2(3:1)=0.16; P>0.5) ratio in the progeny ofheterozygous plants, which suggests that the nef1-1is controlled by a single recessivegene. The genetic complementation experiment result confirmed that the mutationof NEF1gene caused the male-sterile phenotype. The barely normal undulatedplasma membrane and defective sporopollenin accumulation in this mutant wereclearly revealed by TEM examination. Lack of NEF1function leads to a severereduction of the CalS5expression and a decrease of the callose synthesis resulting informing a thinner callose wall, which suggests that this defective callose wall shouldbe a otherwise cause of the abnormality of plasma membrane. Subcellularlocalization analysis confirmed that NEF1encodes a protein localized to plasmamembrane with27transmembrane domains. In situ hybridization results showedthat the microspores and tapetum are the main sites for the specific expression ofNEF1during tetrad stage. Because NEF1also has sequence similarity totransporter-like proteins, NEF1could be an envelope protein that functions as atransporter. The possible role of NEF1might be to deliver essential polysaccharidematerials for the primexine synthesis as a transporter on the membrane ofmicrospores. These results provide several clues for understanding the function ofthese proteins related with the primexine formation.