Aristotle University of Thessaloniki, Department of Agriculture, Laboratory of Agricultural Chemistry, University Campus, 54124 Thessaloniki, Greece.
J Plant Physiol. 2009 Nov 15;166(17):1904-13. doi: 10.1016/j.jplph.2009.06.012. Epub 2009 Jul 23.
We tested whether pre-treatments of roots with H(2)O(2) (10mM for 8h) or sodium nitroprusside (SNP; 100microM for 48h), a donor of ()NO, could induce prime antioxidant defense responses in the leaves of citrus plants grown in the absence or presence of 150mM NaCl for 16d. Both root pre-treatments increased leaf superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) activities, and induced related-isoform(s) expression under non-NaCl-stress conditions. When followed by salinity, certain enzymatic activities also exhibited an up-regulation in response to H(2)O(2) or SNP pre-exposure. An NaCl-stress-provoked decrease in the ascorbate redox state was partially prevented by both pre-treatments, whereas the glutathione redox state under normal and NaCl-stress conditions was increased by SNP. Real-time imaging of ()NO production was found in vascular tissues and epidermal cells. Furthermore, NaCl-induced inhibition in ()OH scavenging activity and promotion of ()OH-mediated DNA strand cleavage was partially prevented by SNP. Moreover, NaCl-dependent protein oxidation (carbonylation) was totally reversed by both pre-treatments as revealed by quantitative assay and protein blotting analysis. These results provide strong evidence that H(2)O(2) and ()NO elicit long-lasting systemic primer-like antioxidant activity in citrus plants under physiological and NaCl-stress conditions.
我们测试了根用 H(2)O(2)(10mM，8h)或硝普钠(SNP;100μM，48h)预处理是否可以诱导在无或有 150mM NaCl 条件下生长 16d 的柑橘植株叶片中初级抗氧化防御反应。两种根预处理均增加了叶片中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)活性，并在非 NaCl 胁迫条件下诱导相关同工酶表达。当随后施加盐胁迫时，某些酶活性也对 H(2)O(2)或 SNP 预处理表现出上调。H(2)O(2)或 SNP 预处理部分阻止了盐胁迫引起的抗坏血酸氧化还原状态下降，而 SNP 则增加了正常和盐胁迫条件下的谷胱甘肽氧化还原状态。在血管组织和表皮细胞中发现了 ()NO 产生的实时成像。此外，SNP 部分阻止了 NaCl 诱导的 ()OH 清除活性抑制和 ()OH 介导的 DNA 链断裂促进。此外，如定量测定和蛋白质印迹分析所示，两种预处理均完全逆转了 NaCl 依赖性蛋白氧化(羰基化)。这些结果有力地证明了 H(2)O(2)和 ()NO 在生理和 NaCl 胁迫条件下诱导柑橘植株产生持久的系统初级抗氧化活性。
