The Agrobacterium-Mediated Transformation Of Tobacco And Stress-Tolerance Of ZmABA2 Gene

Abscisic acid (ABA) is a very important plant hormone. It plays an extremely important role in the growth and development of plants in response to drought and salt stress and other environmental stress. Under stress,the plant will make a series of stress response, prompting a large number of ABA-induced gene expressions. This process mainly through activation of ABA synthesis and inhibit its degradation to improve the content of ABA, thereby enhancing resistance. After removing the stress, ABA rapidly degraded, the content is reduced.In this study, ZmABA2 gene expression in roots, stems, leaves, and H2O2. Temperature, damage, salt stress, drought stress and plant hormone ABA, ETH, BR, etc. can cause ZmABA2 transcript level upregulation. ZmABA2 gene belongs to SDR family,cDNA full length of 1090 bp, ORF of 852 bp, encoding 283 amino acids capable of an average molecular weight of 29.349 KD, isoelectric point of 5.75. The amino acid sequence encoded by the ZmABA2 having 58% homology with AtABA2 gene, but its specific biological function is not clear.Agrobacterium-mediated is an effective means of tobacco genetic transformation. ZmABA2 gene was cloned from maize. Build ZmABA2 gene overexpression vectors. The overexpressing vector were successfully transferred to tobacco, and obtained ZmABA2 gene overexpression tobacco. Treated the overexpression and wild-type tobacco leaves 6h with 200mM NaCl and 20% PEG. Measured the content of the main product of membrane lipid peroxidation MDA and electrolyte leakage, which can reflect the relative permeability of the plasma membrane. And measured ABA content in leaves by high performance liquid chromatograpHy (HPLC). The 5-day-old seedlings of overexpression and wild-type tobacco were transferred to MS solid medium contain 200mM NaCl or osmotic potential is-0.7Mpa, and statistics of the seedling primary root length after 12d. A-month-old tobacco plants of overexpression and wild-type treated with 400mM NaCl or natural drought, pHenotypic analysis after 14 days. The mutant and wild-type tobacco seeds were sown on MS solid medium contain 100mM NaCl or osmotic potential is -0.5Mpa, analysis of germination.The results show that under stress, MDA content and electrolyte leakage of mutant plants is lower than the wild- type plants significantly, ABA content of mutant leaves is higher than the wild- type leaves significantly, primary root length of mutant seedlings is longer than the wild-type seedlings significantly, wilting degree of mutant plants is higher than the wild-type plants significantly, germination of mutant seeds were later than the wild-type seeds.In summary, elevated ZmABA2 gene expression level can improve stress tolerance, increase ABA content in plants, and delay seed germination.