Involvement of reactive oxygen species generated from melanin synthesis pathway in phytotoxicty of L-DOPA
Involvement of reactive oxygen species generated from melanin synthesis pathway in phytotoxicty of L-DOPA
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DOI：
10.1007/s10886-005-1338-9
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发表时间：
2005-02-01
影响因子：
2.3
通讯作者：
Matsumoto, H
中科院分区：
文献类型：
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作者：
Hachinohe, M;Matsumoto, H
(L)-DOPA是一种抑制植物生长的活性化感化学物质。为了确定其植物毒性是否是由于其氧化黑色素过程中产生的活性氧，我们在(L)- dopa耐受性（稗草）和(L)- dopa易感性（生菜）植物以及悬浮培养的胡萝卜细胞中研究了氧化损伤、黑色素积累以及抗氧化剂对其植物毒性的影响。(L)与稗草相比，dopa抑制了生菜的根伸长。(L)- dopa处理的生菜根部黑色素和硫代巴比妥酸活性物质（TBARS）水平显著升高，而稗草则无显著升高。(L)-DOPA对胡萝卜细胞生长的抑制作用为1 mM时的60%，1 mM (L)-DOPA处理的胡萝卜细胞中黑色素含量不断增加；然而，抗坏血酸和α -生育酚抑制积累。当抗坏血酸和α -生育酚抑制黑色素形成时，(L)- dopa处理的细胞恢复生长。1 mM (L)-DOPA处理胡萝卜细胞的TBARS水平在处理后第2天高于未处理的对照细胞，但在第4天和第6天则没有。抗坏血酸和α -生育酚在最初的2天抑制了过氧化脂质的产生。这些结果表明(L)-DOPA的植物毒性是由于黑色素合成途径中活性氧引起的氧化应激所致。
(L)-DOPA is an active allelochemical that inhibits plant growth. To determine whether the phytotoxicity is due to the reactive oxygen species generated during its oxidation to melanin, oxidative damage, melanin accumulation, and the effect of antioxidants on its phytotoxicity were examined in (L)-DOPA-tolerant (barnyard grass) and -susceptible (lettuce) plants, and in suspension-cultured carrot cells. (L)-DOPA suppressed root elongation in lettuce compared to barnyard grass. Levels of melanin and thiobarbituric acid reactive substances (TBARS) increased remarkably in (L)-DOPA-treated lettuce roots, but not in barnyard grass. (L)-DOPA also suppressed carrot cell growth to 60% of the control at 1 mM. Melanin content in 1 mM (L)-DOPA-treated carrot cells increased continuously; however, ascorbic acid and alpha-tocopherol suppressed accumulation. When melanin formation was inhibited by ascorbic acid and alpha-tocopherol, growth of (L)-DOPA-treated cells was restored. TBARS levels were higher in 1 mM (L)-DOPA-treated carrot cells than in untreated control cells 2 d after treatment, but not at 4 or 6 d. Ascorbic acid and alpha-tocopherol suppressed the production of lipid peroxide during the initial 2 d. These results suggest that the phytotoxicity of (L)-DOPA is due to oxidative stress caused by reactive oxygen species from the melanin synthesis pathway.