The Studies On Salt Tolerance And Drought Resistance Of A Wheat DELLA Gain-of-function Mutant Aibian 1 Seedling

Wheat(Triticum aestivum L.) is one of the main cultivated crops and one of the most important food crops in China, which occupies an important position in China’s grain crops. In its’ growth cycle(from winter to next summer), the more hazards of temperature, moisture, minerals occur in wheat than did in other crops. DELLA proteins are important negative regulators in GA(gibberellin) signal pathway. In the studies about model plants Arabidopsis thaliana showed that DELLA proteins are important proteins between environment signals and other plant hormone pathways; and they could respond to light, ethylene, ABA and the auxin pathway, and play an important role when plant suffered biotic and abiotic stress conditions. There are many studies about DELLA proteins in resistance to biotic and abiotic stress in model plant Arabidopsis thaliana, but the research about DELLA proteins in wheat were little and only in regulating plant height.In this study, the gain of DELLA mutants Aibian 1 and other three wheat materials, Chinese Spring, Jing 411, Aiganzao were used as the test materials.(1) Immunoblot analyses were employed to assess the DELLA protein abundances in the 4 cultivars to make sure that Aibian 1 is an DELLA gain-of-function mutant.(2) Total chlorophyll content, relative water content, malondialdehyde(MDA) content and superoxide dismutase(SOD) activity were detected to evaluate their abilities on salt resistance.(3) Plant height, dry matters, the relative water loss rate and survival rate were analysed to assess the drought resistance of 4 wheat materials.The results showed that:(1) Immunoblot analyses showed that Aibian 1 accumulated the highest level of DELLA protein among 4 cultivars.(2) Under salt stress conditions, Aibian 1 showed no clear withering leaves, but the other three cultivars(Chinese spring, Jing 411 and Aiganzao) displayed wilting and yellow leaves. Compared with other three cultivars, Aibian 1 possessed the least loss on chlorophyll content, relative water content and SOD activity in leaf during salt treatment. Additionally, Aibian 1 had the lowest levels of MDA content after salt treatment among the 4 cultivars.(3) Under drought conditions, the high relative declined most among them, while Aibian 1 showed the least at 9.1%. The dry matters were detected and showed that compared with the other cultivars, Aibian 1 contained the higher dry matters. Chinese spring the relative water loss rate of Chinese spring at 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h were respectively decreased by 22.6%, 28%, 14.6%, 8% and 6.3%; the relative water loss rate of Jing 411, Aiganzao, Aibian 1 were respectively 17.3%, 14.4%, 12.6%, 10.2%,8.2%; 22.4%, 24.6%,16.3%, 15.1%, 14.6 % and 10.4%, 13.3%, 11.7%, 9.3%, 7.2%; Aibian 1 showed a high survival rate in drought condition, 84%, the lowest survival rate of Chinese spring, only 29%, the survival rate of Aiganzao and Jing 411 were 43% and 63% respectively. Our data suggested that the the gain of DELLA mutants Aibian 1 showed the high ability to salt resistance and drought stress. Thus, it need worthy of much more explore of Aibian 1 in wheat salt resistant breeding.