Transcriptional Research Of A Key Transcriptional Factor, DYT1for Tapetum Development In Arabidopsis

Anther is the male reproductive organs of plants which is the place forpollen development. Therefore, the study of anther and pollendevelopment has important theoretical significance. As the male-sterilevarieties are valuable resources that greatly facilitate the production ofhybrids via cross-pollination, in-depth study of anther and pollendevelopment has important application value. Pollen developmentdepends on the diploid sporophytic cell layer, especially the tapetal cells.The tapetum, which arises from secondary parietal cells, surroundsdeveloping reproductive cells. It plays an important role in pollendevelopment by contributing to microspore release, nutrition, pollen-wallsynthesis and sporopollenin deposition. The precise regulation of severalkey genes is required for the normal tapetal development. Severaltranscription factors have been reported to form a genetic pathway intapetal development in Arabidopsis. Among them, DYSFUNCTIONALTAPETUM1(DYT1) acts as the upper regulation factor in the geneticpathway and plays an essential role for early tapetal development. In dytl,atfer the cell fate determination, the tapetal cells become severe vaculatedand lost biological functions. However, the regulatory relationshipbetween DYT1and other factors have not been identified yet. Here, we1)construct DYT1-GFP fusion complementary lines to analyze theexpression of DYT1protein. The results showed that the protein of DYT1 were accumulated strictly in tapetal cells at stage5-6, which was differentfrom its transcriptional pattern;2) The Chromatin Immunoprecipitation(ChIP) analysis revealed that DYT1could directly regulates theexpression of Defective in Tapetal Development and Function1(TDF1)for tapetum development in vivo;3) We performed the transgenic rescueassay with expression construct of TDF1drived by DYT1promoter. Inthe transgenic rescue line, the expression of downstream transcript factorsand the sporopollenin synthesis-related genes were recovered.Histochemical staining showed that sporopollenin materials were presentin the tapetal cells of rescure lines. These results suggested that DYT1execute its partial biological functions through TDF1. However，thetapetum development still exhibits abnormal, indicated that DYT1mightregulate other essential factors to determine the development of tapetum.