The Role Of CYP86A1 In Response Of Arabidopsis Thaliana To Drought Stress

Drought is one of the major abiotic stresses that restrict the distribution and production of crops in the world.In the course of long-term evolution,plants adapt to the changing environmental stresses from the aspects of physiological metabolism and structure.Suberin usually deposited in the cell walls of certain boundary tissue layers of plants,such as root endodermis,root exodermis,tuber peridermis,and seed coats.Suberin serves as a protective barrier in these tissue layers,controlling water and nutritional element transport,and playing a key role in response of plant to drought stress.Among them,the cytochrome P450 encoded by CYP86A1 gene is a key enzyme in the synthesis of suberin monomers in Arabidopsis thaliana roots.The mutation of CYP86A1 resulted in a 60%decrease in total suberin content in Arabidopsis thaliana roots,and the structure of suberin lamellae in the cyp86a1 mutant was destroyed,but whether this significant decrease in suberin content affected the response to drought stress is still unknow.Therefore,in this study,CYP86A1 gene was used as the entry point to analyze the role of suberin in Arabidopsis response to drought stress.The main results are as follows:1.The drought stress induced the expression of CYP86A1 gene in Arabidopsis roots,and the mutation of CYP86A1 leads to a decrease in suberization of roots in Arabidopsis thaliana.2.Under control condition,compared to wild type,the content of suberin in the cyp86a1mutant decreased resulted in the weakening of the barrier to water,enhanced the root hydraulic conductivity and photosynthetic efficiency.3.In contrast,the photosynthetic capacity of the cyp86a1 mutant rapidly decreased when exposure to short-term drought stress,the root hydraulic conductivity decreased by 34%,the water use efficiency decreased significantly,and the membrane permeability was damaged seriously under short term drought stress.4.After long-term drought stress,the root electrolyte leakage rate in cyp86a1 mutant increased significantly,the K~+concentration,the aerial biomass and tissue water content in cyp86a1 mutant was significantly lower than that in the wild type,and the growth of cyp86a1mutant was inhibited more significantly.All these results revealed the key role of CYP86A1 in drought stress response in Arabidopsis thaliana and providing the direct evidence for the function of apoplastic barrier formed by suberin in drought resistance of plants,providing important theoretical references for pasture and crops improvement by changing the root adaptive structure of plants.