The Molecular Mechanism Of DEX1 Affecting The Pollen Wall Pattern Formation In Arabidopsis

Higher plant has a unique pollen wall.The primexine determines the accumu lation of sporopollenin and pollen wall pattern.DEX1 is a membrane-localized protein.The disruption of DEX1 gene causes the decrease of the primexine of the pollen wall and defective pollen wall pattern,which lead to the male sterility of the dex1.The purpose of this study is to investigate the mechanism of DEX1 in the process of pollen wall pattern formation.We used three different tag to be fused at the N and C-terminal of DEX1,respectively,in order to study the function of DEX1.However,no complemented plants were identified,suggesting that the N and C-terminal of DEX1 play crucial roles in DEX1 function.The immuno-histochemical analysis of DEX1-GFP transgenic plants showed that DEX1 was highly expressed in microsporocyte,microspore,but not in tapetum.When dex1 was placed at low temperature,the fertility cannot recover.However,the control lines(rpg1 and npu-2)became fertile at low temperature,indicating that DEX1 played a unique role in the formation of primexine and the pollen wall pattern,DEX1 has a structure of integrin alpha subunit.In animal cells,the ? and ? integrin are associate with each other to function in several crucial biological processes.Bioinformatics prediction and co-expression analysis revealed that there was a new integrin-like gene DEXY in Arabidopsis thaliana.The dexy knockout mutant also showed male sterility.No pollen can be observed in dexy anther.DEX1 and DEXY might associated with each other to affect pollen wall development,similar to the animal integrins.Our study provides information about the molecular mechanism of DEX1 on pollen wall development.These results suggest that the integrin-like proteins(DEX1 and DEXY)might play crucial roles in primexine formation and pollen wall patterning.