The Preliminary Biological Function Study Of Arabidopsis Thaliana Stomatal Index Regulation Gene AtIQD21

Stomata have played very important roles in regulating the absorption and metabolism of water and nutrient in plants, and the entire ecological environment.Stomatal development in Arabidopsis derived from a series of special events of asymmetric division of protodermal cells and specialized events of cell fate. A complex signaling network mechanisms are regulated by SPCH(SPEECHLESS),MUTE, FAMA genes. And many other genes have also been identified involving in the stomatal development process.We used GENEGIVESTIGATER analysis tools to analyze Arabidopsis genes AtIQD21. First, for the relevant structural features analysis of it, we found that the gene ORF consists of 1419 bp nucleotides, encoding 472 amino acids, while the three IQ domains encoded Ca2+ binding motif. The protein transmembrane region is up to33 amino acids, and a minimum of 17 amino acids. The protein is unstable and hydrophilic. It possibly interacts with OST1(OPEN STOMATAL 1)protein closely.Then we also carried out the cellular localization of the protein analysis, and found it expressed in the nucleus and on cell membrane. By RT-qPCR fluorescence quantitative detection method we detected the expression of the At IQD21 gene in wild-type Arabidopsis tissues and organs, such as roots, stems, leaves, flowers, and the expression level of the genes in the over-expression Arabidopsis mutant plants.the gene is expressed with the highest level in wild-type Arabidopsis flowers, while less level in stems and the roots, and lowest level in leaves. AtIQD21 cDNA was cloned from Arabidopsis wild-type plants, and overexpression vector of this gene was constructed by Gateway recombination cloning technology. Eventually we transformed wild-type Arabidopsis and gained the overexpression mutants successfully. Then we carried out the stomatal index survey of AtIQD21 gene deletion and overexpression mutants using the improved impression methods of Arabidopsis leaves epidermis. The phenotypic analysis showed the stomatal index of AtIQD21 deletion mutant increased significantly compared to the wild-type Arabidopsis, and the stomatal index of AtIQD21 overexpressing mutant was significantly lower than that of wild-type Arabidopsis. These results indicates AtIQD21 may be involved in the regulation of epidermal cell asymmetric division process, and asymmetric division is abnormal once this gene is mutated. This study laid the foundation for the clarification of biological functions of AtIQD21 gene in near future.