Department of Plant Pathology, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.
Department of Microbial Biotechnology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.
PLoS One. 2020 Mar 19;15(3):e0230531. doi: 10.1371/journal.pone.0230531. eCollection 2020.
Among several studied strains, Streptomyces rochei IT20 and S. vinaceusdrappus SS14 showed a high level of inhibitory effect against Phytophthora capsici, the causal agent of pepper blight. The effect of two mentioned superior antagonists, as single or combination treatments, on suppression of stem and fruit blight diseases and reproductive growth promotion was investigated in pepper. To explore the induced plant defense reactions, ROS generation and transcriptional changes of selected genes in leaf and fruit tissues of the plant were evaluated. The plants exposed to the combination of two species responded differently in terms of H2O2 accumulation and expression ratio of GST gene compared to single treatments upon pathogen inoculation. Besides, the increment of shoot length, flowering, and fruit weight were observed in healthy plants compared to control. Likely, these changes depended on the coordinated relationships between PR1, ACCO genes and transcription factors WRKY40 enhanced after pathogen challenge. Our findings indicate that appropriate tissue of the host plant is required for inducing Streptomyces-based priming and relied on the up-regulation of SUS and differential regulation of ethylene-dependent genes.
在研究的几种菌株中，罗氏链霉菌 IT20 和 SS14 葡萄球菌对辣椒疫病的病原菌辣椒疫霉表现出了很高的抑制作用。在辣椒上，研究了两种优势拮抗剂（单独或组合处理）对抑制茎和果实疫病以及促进生殖生长的效果。为了探究诱导的植物防御反应，评估了叶片和果实组织中 ROS 的产生和选定基因的转录变化。与单独处理相比，暴露于两种物种组合下的植物在受到病原菌接种时，H2O2 积累和 GST 基因表达比率表现出不同的反应。此外，与对照相比，健康植物的枝条长度、开花和果实重量都有所增加。可能这些变化取决于 PR1、ACCO 基因和转录因子 WRKY40 之间的协调关系，这些基因在受到病原菌挑战后增强。我们的研究结果表明，宿主植物的适当组织需要用于诱导基于链霉菌的启动，并且依赖于 SUS 的上调和乙烯依赖性基因的差异调控。
