Preliminary Studies Of The Role Of Auxin Gradient During Organogenesis In Arabidopsis Thaliana

Plants, compared to animals, show an amazing adaptability and plasticity in their development. This is mainly dependent on the ability of plants can form new post-embryonic organs, such as lateral roots, leaves, branches, flowers and so on. Through the coordination of cell division and differentiation, founder cells can form to organ primordial and eventually develop into the mature organs. Organ formation in Arabidopsis involves dynamic gradients of the signaling molecule auxin with maxima at the primordia tips. Using the model plant Arabidopsis, enrich our understanding on the functions of auxin in plant organogenesis, therefore explored the function of auxin also become to one of the most popular research areas in developmental biology. This paper, Arabidopsis as the material, through research the role of auxin in post-embryo organogenesis, and found that the formation of lateral root primordia along with the establishment of auxin gradients, and the formation of auxin gradient made lateral root primordia has an independent meristematic capacity. The formation of auxin gradient related with the auxin transport and response proteins, and the mutations of auxin-related gene reduced the lateral roots numbers in different levels, in addition to auxin export protein——PIN family in the process of lateral root primordial formation, and their different orientation indicate their different effects on the auxin gradient formation. Meanwhile, in order to further study the functions of auxin gradient in plant organogenesis, using the boundary gene CUC3 promoter made the auxin synthetase expression in organ initiation border, construction of transgenic plants, aimed that through interference endogenous auxin gradient in organ initiation process and study the effect of auxin gradient on plant organogenesis. Our results show that transgenic plants with many phenotypes, such as leaf curling, leaf area reduced, accelerated growth, lateral roots and branches reduced, hypocotyls longer, stems and leaves with the starting position abnormal and some abortion. Some of these phenotypes is similar to the reported function of auxin synthetase yucc6 gain of function mutant phenotype, and the other part is similar to cuc3 mutant phenotypes, moreover, the remaining phenotypes were mainly due to interference with auxin gradient in the process of lateral organ initiation caused. These results suggest that auxin gradient play a crucial role in the formation and maintenance of the organs and their later development.