Role of exogenous salicylic acid in regulating physio-morphic and molecular changes under chromium toxicity in black- and yellow- seeded Brassica napus L.
Role of exogenous salicylic acid in regulating physio-morphic and molecular changes under chromium toxicity in black- and yellow- seeded Brassica napus L.
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DOI：
10.1007/s11356-016-7167-2
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发表时间：
2016-10-01
影响因子：
5.8
通讯作者：
Zhou, Weijun
中科院分区：
文献类型：
--
作者：
Gill, Rafaqat A.;Zhang, Na;Zhou, Weijun
水杨酸（SA）介导植物对广泛的生物和非生物胁迫的耐受机制。因此，本研究旨在研究在铬（Cr）胁迫下，SA如何调控两个油菜品种（Brassica napus L.）的植物保护机制。外源施加SA能促进植物生长，增加干生物量，并通过改善因Cr中毒而严重受损的细胞器来增强活性氧清除系统。与黑色品种zs758相比，黄色品种浙大622的根和叶中Cr含量均显著提高。外源施用SA显著降低了Cr胁迫下两个器官的Cr含量，并提高了SA含量。Cr胁迫下活性氧（ROS）的生成呈剂量依赖性增加。为了缓解活性氧的有害作用，Cr胁迫下植物的防御系统被诱导，SA进一步增强了保护作用。电镜观察结果显示，铬胁迫显著破坏了两个品种的细胞器，增加了淀粉粒的大小和质体舌球的数量，破坏了叶绿体和线粒体结构。然而，外源施用SA后，两个品种的植物细胞明显恢复了这些损伤。结果表明，品种zs758对铬的耐受性较好。基因表达分析表明，Cr和SA联合处理增加了两个品种抗氧化相关基因的表达。本研究结果表明，SA诱导两种油菜品种根、叶在Cr胁迫下的酶抗氧化活性及相关基因表达、次生代谢，改善细胞结构变化和特定胁迫相关蛋白转录水平。
Salicylic acid (SA) mediates tolerance mechanisms in plants against a wide spectrum of biotic and abiotic stresses. Therefore, the present study was carried out to determine how SA regulates the plant protection mechanisms in two cultivars of oilseed rape (Brassica napus L.) under chromium (Cr) stress. Exogenously applied SA enhanced plant growth, increased dry biomasses, and strengthened the reactive oxygen scavenging system by improving cell organelles that were severely damaged via Cr toxicity. The contents of Cr were significantly enhanced in both root and leaf of cultivar Zheda 622 (yellow color) compared with cultivar ZS 758 (black color). Exogenous application of SA significantly reduced the Cr contents in both plant organs as well as enhanced the SA contents under Cr stress. A dose-dependent increase was observed in reactive oxygen species (ROS) generation under Cr stress. To ease the inimical effects of ROS, plants' defense systems were induced under Cr stress, and SA further enhanced protection. Further, TEM micrographs results showed that Cr stress alone significantly ruptured the plant cell organelles of both cultivars by increasing the size of starch grain and the number of plastoglobuli, damaging the chloroplast and mitochondrion structures. However, exogenously applied SA significantly recovered these damages in the plant cells of both cultivars. It was also observed that cultivar ZS 758 was proved to be more tolerant under Cr toxicity. Gene expression analysis revealed that combined treatments of Cr and SA increased antioxidant-related gene expression in both cultivars. Findings of the present study demonstrate that SA induces the enzymatic antioxidant activities and related gene expression, secondary metabolism, and improves the cell structural changes and the transcript level of specific stress-associated proteins in root and leaf of two oilseed rape cultivars under Cr toxicity.