Soaking in H2O2 regulates ABA biosynthesis and GA catabolism in germinating cotton seeds under salt stress
2017
Kong, Xiangqiang | Luo, Zhenren | Zhang, Yanjun | Li, Weijiang | Dong, Hezhong
Exogenous H₂O₂ improves seed germination with the involvement of ABA and GA in a number of plant species but how it affects cotton seed germination under salinity stress is not well documented. In this study, we found that the marked inhibition of cotton seed germination under salinity stress was considerably alleviated by pretreatment with H₂O₂. Salt stress increased the ABA content by upregulating ABA biosynthesis genes, NCED2, NCED5 and NCED9 and downregulating the ABA catabolism gene, CYP707A2. It also decreased the GA content by increasing the expression of GA catabolism gene, GA2ox1 and decreasing that of the GA biosynthesis gene, GA20ox1 during germination. Pretreatment with H₂O₂ downregulated the ABA biosynthesis genes, NCED5 and NCED9, thereby decreasing the ABA content in germinating seeds. Concurrently, it increased the GA content by downregulating the GA catabolism gene, GA2ox1. These results suggest that pretreatment with H₂O₂ improved cotton seed germination by mediating the downregulation of ABA catabolism and GA biosynthesis under salt stress.
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