The Ramie Auxin-binding Proteins (BnABP1) Gene CDNA Transformation And Over Expressed In Elongate Cells

Recent studies on auxin binding protein (ABP1) in some model plants have made great progress and provided much information to understand the molecular mechanism of auxin binding protein. But the precise function of ABP1 especially in its involvement in cell elongation is requiring further study. In this study that the ABP1 cDNA of Ramie (BnABP1) that we cloned previously was recombinated with the cotton fiber-specific expression E6 promoter and transformed into Arabidopsis and Cotton. It is expected to overexpress in some typically elongate plant cells such as Arabidopsis trichome and Cotton fibre cell.We cloned a fiber-specific highly expression gene E6 promoter of Cotton by PCR. To verifiy its activity that we recombinated it with a GUS report gene and transformed into Arabidopsis at first. The GUS histochemical assay of the transgenics shows that the color reaction is observed not only in trichomes but also in floral organ, stem and radicle. But the most obvious blue is in the trichomes. It demanstrats the E6 promoter is not a so specific promoter only express in trichome. But it is expression higher in trichome cells suitable for our research.The BnABPl cDNA is then cloned into the T-DNA region of a Ti binary vector pBI121 with the cotton source E6 promoter. The constructed vector was named of pB1121-E6-BnABP1. The vector was transformed into Agrobacterium tumefaciens GV3101 via Freeze-thaw and then transformed into Arabidopsis of Columbia-type via floral dip with the bacteria. Some 3 transformed seedlings were screened out and the trichome phenotype of the leaf was subject to observation. The E6 promoting specific expression of BnABP1 in trichomes makes the trichome elongate to 10% longer than the wild type and the leaf in a pileous morphology. The transgenic Arabidopsis are growth in an enhanced manner with the enlarged rossete leaf and more bolting number. It is conclude that the BnABP1 expression in trichome influence the development of the trichomes. It confirmed that the ABP1 is an auxin signal parternar involoved in cell elongation.Cotton fiber and Arabidopsis trichome are homologous in development. Therefore, it will bring benefits to the improvement of cotton fiber quality if any studies about Arabidopsis trichomes made any progress. In order to confirm this possibility that the ABP1 effectiveness in quality improvement of cotton fiber, we tried the transformation of cotton with pBI121-E6-BnABP1. Because the classical cotton transformation is rather noefficiently we developed a new cotton transformation routine by ovary injection of agrobacterium. In a total of 8 cultivated varieties of Gossypium hirsutum are transformed in planta bacteria injection. The cotton flower in the stage of-48 h (-2 DPA) to 24 h (1 DPA) of fertilization showes the injected stain in its ovule in a pre-experiment. So we set the suitable injection stage of 24 h after feritilization. The agrobacterium of almost 104 cells were injected into the ovary 24 h after fertilization. The transformation for the eight varieties shows that this method has a reasonable transformation effect with no significant correlation with the genotype. The BnABP1 function in fibre cell elongation and quality is still under investigation.