The PIN Genes Expression And Its Relationship To Carpel Morphogenesis Of Capsella Bursa-pastoris

Auxin is a major regulator in coordination of plant growth, development and morphogenesis. The polar transportation of auxin leads to a gradient distribution and forms of maximum which will affect such as bilateral symmetry, vascular differentiation and organ development and all the other developmental processes.The Arabidopsis thaliana and Capsella bursa-pastoris are both belong to cruciferous plant that share similar genetic background and physical characters. But they are apparently different in their shape of carpel and pod. The Arabidopsis thaliana’s carpel is dicarpellary and develops to a cylindrical silique. But Capsella bursa-pastoris’s carpel is in the shape of triangle and with the heart shape silicle. Because auxin polar transport is critical in the morphogensis of plant ogans that we focus on auxin polar transport in the development of Arabidopsis thaliana and Capsella bursa-pastori’s in carpel in this study.The Real-time quantitative PCR are applied to quantify same key auxin polar transpoter genes such as PIN1、PIN3and PIN7. Their expression in root, stem, leaf and flower tissues are tested with the fi-actin as reference gene. The results showed that the three genes are in different expression level in different tissues. The PIN1expression in Arabidopsis thaliana is highest in its flower, followed by the stem and root but is lowest in the leaf. The expression of PIN1in Capsella bursa-pastoris is degrading in root, stem, leaf that is consistent with it is in Arabidopsis thaliana, but its expression in flower is much lower than it is in the Arabidopsis thaliana. The expression of PIN1in Arabidopsis thaliana is ten times more compared to it is in Capsella bursa-pastoris. The expression of PIN3decreased gradually in Arabidopsis thaliana from root to stem to flower and leaf, but its expression decreased gradually in Capsella bursa-pastoris from stem to root to flower and leaf. The expression of PIN3in Capsella bursa-pastoris is ten times compared to it is in the Arabidopsis thaliana. The expression of PIN7is high in Arabidopsis thaliana leaf and flower, but is low in root and stem while in Capsella bursa-pastoris it is in a close level in root, stem and flower but is apparently high in leaf. As in a whole the expressions of PIN1and PIN7are higher in all the tissues in Arabidopsis thaliana than they are in Capsella bursa-pastoris. In the contrary, the expression of PIN3in the tissues of Capsella bursa-pastoris is higher than it is in Arabidopsis thaliana.Because the expression of PIN3in Capsella bursa-pastoris is higher than Arabidopsis thaliana and PIN3is the major gene relevant to lateral auxin polar transportation. So we designed a transgenic research in Arabidopsis with inducible PIN3expression. We cloned Capsella bursa-pastori’s PIN3(CbPIN3) cDNA and recombinate into the Ti plasmid pER16, an inducible plant transform vector. The recombinated pER16::CbPIN3can be induced by estradiol in plant. We then transform Arabidopsis thaliana ecotype Columbia by Agrobacterium tumefaciens mediated inflorescence infiltration. Same transgenic seedlings are screened out and determined. When the transgenic Arabidopsis thaliana was in bloom we induced the tansgene expression with estradiol. The morphology of the carpels development is observed that Arabidopsis thaliana carpel was maintaining its long cylindrical shape in a whole but is bending in curve in its shape. This seems that the CbPIN3induced expression in Arabidopsis thaliana carpel may affect the auxin bilateral distribution lead to same unequal dividing of cells caused the bending of carpel. The morphogenesis of the silique or silicle is a more complicated process that can not only determined by PIN3.