Plant Biotechnology Laboratory, Drug Development/Diagnostics and Biotechnology Division, Indian Institute of Chemical Biology (A unit of Council of Scientific and Industrial Research), 4, Raja S. C. Mullick Road, Kolkata 700-032, India.
Planta. 2011 May;233(5):895-910. doi: 10.1007/s00425-011-1349-4. Epub 2011 Jan 15.
The elaborate networks and the crosstalk of established signaling molecules like salicylic acid (SA), jasmonic acid (JA), ethylene (ET), abscisic acid (ABA), reactive oxygen species (ROS) and glutathione (GSH) play key role in plant defense response. To obtain further insight into the mechanism through which GSH is involved in this crosstalk to mitigate biotic stress, transgenic Nicotiana tabacum overexpressing Lycopersicon esculentum gamma-glutamylcysteine synthetase (LeECS) gene (NtGB lines) were generated with enhanced level of GSH in comparison with wild-type plants exhibiting resistance to pathogenesis as well. The expression levels of non-expressor of pathogenesis-related genes 1 (NPR1)-dependent genes like pathogenesis-related gene 1 (NtPR1), mitogen-activated protein kinase kinase (NtMAPKK), glutamine synthetase (NtGLS) were significantly enhanced along with NtNPR1. However, the expression levels of NPR1-independent genes like NtPR2, NtPR5 and short-chain dehydrogenase/reductase family protein (NtSDRLP) were either insignificant or were downregulated. Additionally, increase in expression of thioredoxin (NtTRXh), S-nitrosoglutathione reductase 1 (NtGSNOR1) and suppression of isochorismate synthase 1 (NtICS1) was noted. Comprehensive analysis of GSH-fed tobacco BY2 cell line in a time-dependent manner reciprocated the in planta results. Better tolerance of NtGB lines against biotrophic Pseudomonas syringae pv. tabaci was noted as compared to necrotrophic Alternaria alternata. Through two-dimensional gel electrophoresis (2-DE) and image analysis, 48 differentially expressed spots were identified and through identification as well as functional categorization, ten proteins were found to be SA-related. Collectively, our results suggest GSH to be a member in cross-communication with other signaling molecules in mitigating biotic stress likely through NPR1-dependent SA-mediated pathway.
植物防御反应中，水杨酸 (SA)、茉莉酸 (JA)、乙烯 (ET)、脱落酸 (ABA)、活性氧 (ROS) 和谷胱甘肽 (GSH) 等已确立信号分子的精细网络和串扰发挥着关键作用。为了深入了解 GSH 参与这种串扰以减轻生物胁迫的机制，我们生成了转 Lycopersicon esculentum γ-谷氨酰半胱氨酸合成酶 (LeECS) 基因的 Nicotiana tabacum 超表达系 (NtGB 系)，与野生型植株相比，这些植株中的 GSH 水平升高，同时表现出对致病性的抗性。非致病性相关基因 1 (NPR1) 依赖基因如致病性相关基因 1 (NtPR1)、丝裂原活化蛋白激酶激酶 (NtMAPKK)、谷氨酰胺合成酶 (NtGLS) 的表达水平显著增强，同时 NtNPR1 的表达水平也增强。然而，NPR1 不依赖基因如 NtPR2、NtPR5 和短链脱氢酶/还原酶家族蛋白 (NtSDRLP) 的表达水平要么不显著，要么下调。此外，还观察到硫氧还蛋白 (NtTRXh)、S-亚硝基谷胱甘肽还原酶 1 (NtGSNOR1) 的表达增加和异分支酸合酶 1 (NtICS1) 的抑制。以时间依赖性方式对 GSH 喂养的烟草 BY2 细胞系进行综合分析，与体内结果相呼应。与坏死性Alternaria alternata 相比，NtGB 系对生物寄生性 Pseudomonas syringae pv. tabaci 的耐受性更好。通过二维凝胶电泳 (2-DE) 和图像分析，鉴定出 48 个差异表达斑点，通过鉴定和功能分类，发现 10 种蛋白与 SA 相关。总的来说，我们的研究结果表明 GSH 可能通过 NPR1 依赖的 SA 介导途径与其他信号分子进行交叉通讯，从而减轻生物胁迫。
