PJB-2018-1773
The application of exogenous gibberellic acid enhances wheat seedlings UV-B tolerance by ameliorating DNA damage and manipulating UV-absorbing compound biosynthesis in wheat seedling leaves
Limei Gao, Xiaofei Wang, Zhihua Shen and Yongfeng Li
Abstract
DNA damage is one of the key parameters to detect UV-B tolerance because DNA is one of the primary targets for UV-B light. Here, we evaluated UV-B stress-induced genomic DNA damages and its self-repair ability in wheat seedlings with or without gibberellic acid (GA3) treatment. The application of exogenous GA3 exhibited the better phenotypic development, less inhibition effects in biomass production and a lower accumulation level of cyclobutane pyrimidine dimer (CPD) and (6-4) photoproducts (6-4PPs) in leaves of wheat seedlings under supplementary UV-B stress than those without GA3 treatment, indicating that GA3 ameliorated the detrimental effects and DNA damages induced by the enhanced UV-B stress, in which the 150mg L-1 of GA3 is the most effective treatment. After exogenous GA3 treatment, the UV-absorbing compounds (UACs) contents and DNA photolyase activity also significantly increased, whereas reactive oxygen species (ROS) production were similar between two groups with or without GA3 application under UV-B stress. These results have demonstrated that GA3 enhanced wheat seedlings UV-B tolerance by initiating DNA damage repair pathway in leaves of wheat seedlings exposed to supplementary UV-B stress, which were mainly implemented through activating DNA photorepair capability and elevating UV-B absorbance amounts in vivo in plants.
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