Department of Biotechnology, Guru Nanak Dev University, Amritsar, Punjab, India.
Department of Agriculture, Guru Nanak Dev University, Amritsar, Punjab, India.
Plant Biol (Stuttg). 2023 Aug;25(5):757-770. doi: 10.1111/plb.13548. Epub 2023 Jun 16.
Withania somnifera is an important medicinal plant, however, its cultivation and quality are compromised through infestation by leaf spot disease caused by the fungus, Alternaria alternata. To find suitable strategies against this disease, studies on post-infectional changes are important. ROS are critical as they interact with other defence signalling pathways. We analyzed ROS-generating and scavenging systems in healthy and diseased leaf samples of W. somnifera and ROS-driven downstream defence pathways. We used DAB and NBT assays for ROS detection, spectrophotometry and in-gel assays for ROS scavenging enzymes, a thioglycolic acid (TGA) based assay, histochemical staining for lignin, and qRT-PCR for transcript-level expression. Leaf spot infection in W. somnifera increased NADPH oxidase activity and ROS accumulation in infected leaves, together with enhanced antioxidant enzyme activity. Leaf spot-infected leaves had increased lignin content and higher expression of lignin biosynthesis genes. In addition, transcript levels of defence-related genes, NPR1 and PR, were also upregulated. The present work provides insights into responses to leaf spot disease through defence-related signalling in W. somnifera. It demonstrates crosstalk between ROS and lignin biosynthesis. This work identified potential targets for developing strategies to confer disease resistance against A. alternata in W. somnifera.
睡茄是一种重要的药用植物，然而，其种植和质量受到由Alternaria alternata 真菌引起的叶斑病的影响。为了找到针对这种疾病的合适策略，对感染后的变化进行研究很重要。ROS 很重要，因为它们与其他防御信号通路相互作用。我们分析了健康和患病的睡茄叶片样本中的 ROS 生成和清除系统以及 ROS 驱动的下游防御途径。我们使用 DAB 和 NBT 测定法检测 ROS，使用分光光度法和凝胶内测定法检测 ROS 清除酶，使用基于巯基乙酸（TGA）的测定法检测木质素，使用 qRT-PCR 检测转录水平的表达。在睡茄中，叶斑病感染会增加 NADPH 氧化酶活性和感染叶片中的 ROS 积累，同时增强抗氧化酶活性。感染叶斑病的叶片木质素含量增加，木质素生物合成基因的表达水平升高。此外，防御相关基因 NPR1 和 PR 的转录水平也上调。本研究通过睡茄中的防御相关信号转导提供了对叶斑病反应的深入了解。它表明了 ROS 和木质素生物合成之间的串扰。这项工作确定了在睡茄中针对 A. alternata 开发抗病策略的潜在目标。
