Alleviated aluminum toxicity by exogenous nitric oxide in wheat: toward regulating the ascorbate-glutathione cycle

• 1、College of Natural Resource & Environmental Sciences, Zhejiang university, 310058

Abstract：The possible association with nitric oxide (NO) and ascorbate-glutathione (AsA-GSH) cycle in regulating aluminum (Al) tolerance of wheat was investigated using two genotypes with different Al resistance. Exposure to Al inhibited root elongation, triggered lipid peroxidation and oxidation of AsA and GSH to dehydroascorbate and glutathione disulfide, respectively, in wheat roots. Exogenous NO significantly increased endogenous NO levels, and subsequently alleviated Al-induced inhibition of root elongation and oxidation of AsA and GSH to maintain the redox molecules in reduced form in both wheat genotypes. Under Al stress, significantly increased activity and gene transcriptional level of ascorbate peroxidase, glutathione reductase, and dehydroascorbate reductase, were observed in the root tips of the Al-tolerant genotype Jian-864. NO application enhanced the activity and gene transcriptional level of all the above mentioned enzymes in both wheat genotypes. γ-Glutamylcysteine synthetase was not significantly affected by Al as well as NO, but NO treatments increased glutathione peroxidase and glutathione S-transferase activity to a greater extent than the Al-treated wheat seedlings. Proline was significantly decreased by Al, while was not affected by NO. These results clearly suggest the role of NO in providing protection against Al-induced oxidative stress which possibly through its regulation of the AsA-GSH cycle.

keywords： aluminum ascorbate glutathione nitric oxide reactive oxygen species wheat.

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