Molecular Mapping And Functional Analysis Of An Arabidopsis Thaliana Gene Controling Pollen Grain Formation

Anther and pollen development is one of the most important areas in plantdevelopment biology. The defective of anther and pollen development will result in malesterility. Male-sterile mutants have been identified in many higher plants. It is an efficientstrategy to investigate the molecular mechanisms of plant anther and pollen develop bycloning genes from male-sterile mutants followed by functional analysis.In this study, the phenotype of an Arabidopsis male sterile mutant EC2-157 was desc-Ibed and the corresponding gene was fine-scale mapped.The mutant shows shorter filamentsthan wild type and there is no pollen grain in the anther. Cytological observation suggeststhat tapetum and middle layer become fatter and have more vacuoles than wild type in stage6 of anther development.Callose staining with particular fluorescence dye-Aniline blue indic-ated that the degradation of callose was delayed.There is no free microspores released fromthe tetrads and no pollen grains were formed in mutant anther.These results showed thatMS157 plays a vital role in anther development by regulating the degradation of the callosewall.ms157 has been mapped to a region of 74kb located in BAC clone T6K22 on chromo-some IV using a map-based cloning strategy. As no male sterile genes have been reportedin this region, we believe that ms157 could be a new male sterile gene.There are 11 genesin this region, but most of them are unknown proteins. As gene expression analysis throu-gh chip database indicated that AT4G21350 and AT4G21370 are specifically expressed inanther,we sequenced and analyzed AT4G21350.On the other hand,we also bought T-DNAtagging lines of these 11 genes from the www.arabidopsis.org web. Phenotype analysisindicated that T–DNA insertion mutant of transcription factor AT4G21330 result in malesteility. The further work to identify MS157 is being undertaken. The molecular cloningand further functional analysis will provide further insight of anther development.