Early induction of Fe-SOD gene expression is involved in tolerance to Mn toxicity in perennial ryegrass

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• 作者：Alej ; ra Ribera-Fonseca ; Claudio Inostroza-Blancheteau ; Paula Cartes ; Zed Rengel ; M.L. Mora
• 关键词：Manganese toxicity ; Manganese tolerance ; Ryegrass ; Oxidative stress ; Superoxide dismutase isoforms ; Fe-SOD ; Gene expression
• 刊名：Plant Physiology and Biochemistry
• 出版年：December, 2013
• 年：2013
• 卷：73
• 期：Complete
• 页码：77-82
• 全文大小：823 K

文摘

Manganese (Mn) toxicity limits plant growth in acid soils. Although Mn toxicity induces oxidative stress, the role of superoxide dismutase (SOD, EC.1.15.1.1) isoforms in conferring Mn tolerance remains unclear. Seedlings of ryegrass cultivars Nui (Mn-sensitive) and Kingston (Mn-tolerant) were hydroponically grown at 2.4 (optimal) or 750聽渭M Mn (toxic) concentration, and harvested from 2 to 48聽h. Kingston showed higher shoot Mn than Nui at 2.4聽渭M Mn. At toxic supply, shoot Mn concentration steadily increased in both cultivars, with Kingston having the highest accumulation at 48聽h. An early (2聽h) increase in lipid peroxidation under Mn excess occurred, but it returned (after 6聽h) to the basal level in Kingston only. Kingston exhibited higher SOD activity than Nui, and that difference increased due to toxic Mn. In general, Mn-induced gene expression of Mn- and Cu/Zn-SOD isoforms was higher in Nui than Kingston. Nevertheless, under Mn excess, we found a greater Fe-SOD up-regulation (up to 5-fold) in Kingston compared to Nui. Thus, Fe-SOD induction in Kingston might explain, at least partly, its high tolerance to Mn toxicity. This is the first evidence that Mn toxicity causes differential gene expression of SOD isoforms in ryegrass cultivars in the short-term.