Glyphosate-induced oxidative stress in Arabidopsis thaliana affecting peroxisomal metabolism and triggers activity in the oxidative phase of the pentose phosphate pathway (OxPPP) involved in NADPH generation
Glyphosate-induced oxidative stress in Arabidopsis thaliana affecting peroxisomal metabolism and triggers activity in the oxidative phase of the pentose phosphate pathway (OxPPP) involved in NADPH generation
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DOI：
10.1016/j.jplph.2017.08.007
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发表时间：
2017-11-01
影响因子：
4.3
通讯作者：
Corpas, Francisco J.
中科院分区：
文献类型：
--
作者：
de Freitas-Silva, Larisse;Rodriguez-Ruiz, Marta;Corpas, Francisco J.
草甘膦是一种广谱内吸性除草剂，在全世界范围内使用。在易受影响的植物中，草甘膦影响莽草酸途径并减少芳香族氨基酸的合成。使用在 20 μM 草甘膦存在下生长的拟南芥幼苗，我们分析了 H2O2、抗坏血酸、谷胱甘肽 (GSH) 和蛋白质氧化含量，以及抗氧化剂过氧化氢酶、超氧化物歧化酶 (SOD) 和抗坏血酸-谷胱甘肽循环酶活性。我们还检查了 NADPH 生成系统的主要成分，包括葡萄糖-6-磷酸脱氢酶 (G6PDH)、6-磷酸葡萄糖酸脱氢酶 (6PGDH)、NADP-苹果酸酶 (NADP-ME) 和 NAD-异柠檬酸脱氢酶 (NADP-ICDH)。草甘膦导致生长参数急剧降低并增加蛋白质氧化。除参与 NADPH 生成的戊糖磷酸途径中的两种氧化相酶 G6PDH 和 6PGDH 外，除草剂还导致 GSH 含量、抗氧化酶活性（过氧化氢酶和抗坏血酸-谷胱甘肽循环的所有酶成分）总体增加。在这项研究中，我们提供了关于 G6PDH 和 6PGDH 参与拟南芥草甘膦诱导的氧化应激反应的新证据，其中过氧化物酶体酶，如过氧化氢酶和乙醇酸氧化酶，受到积极影响。我们认为磷酸戊糖途径 (OxPPP) 氧化相提供的 NADPH 应有助于维持谷胱甘肽还原酶 (GR) 活性，从而在草甘膦诱导的应激下保存和再生细胞内 GSH 库。特别值得注意的是，6PGDH 活性不受促氧化剂和硝化分子（例如 H2O2、一氧化氮或过氧亚硝酸盐）的影响。
Glyphosate is a broad-spectrum systemic herbicide used worldwide. In susceptible plants, glyphosate affects the shikimate pathway and reduces aromatic amino acid synthesis. Using Arabidopsis seedlings grown in the presence of 20 mu M glyphosate, we analyzed H2O2, ascorbate, glutathione (GSH) and protein oxidation content as well as antioxidant catalase, superoxide dismutase (SOD) and ascorbate-glutathione cycle enzyme activity. We also examined the principal NADPH-generating system components, including glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH), NADP-malic enzyme (NADP-ME) and NAD-Pisocitrate dehydrogenase (NADP-ICDH). Glyphosate caused a drastic reduction in growth parameters and an increase in protein oxidation. The herbicide also resulted in an overall increase in GSH content, antioxidant enzyme activity (catalase and all enzymatic components of the ascorbate-glutathione cycle) in addition to the two oxidative phase enzymes, G6PDH and 6PGDH, in the pentose phosphate pathway involved in NADPH generation. In this study, we provide new evidence on the participation of G6PDH and 6PGDH in the response to oxidative stress induced by glyphosate in Arabidopsis, in which peroxisomal enzymes, such as catalase and glycolate oxidase, are positively affected. We suggest that the NADPH provided by the oxidative phase of the pentose phosphate pathway (OxPPP) should serve to maintain glutathione reductase (GR) activity, thus preserving and regenerating the intracellular GSH pool under glyphosate-induced stress. It is particularly remarkable that the 6PGDH activity was unaffected by pro-oxidant and nitrating molecules such as H2O2, nitric oxide or peroxynitrite.