Powdery mildew (PM) is an important disease of pea that reduce yield. Ascophyllum nodosum extract (ANE) and chitosan (CHT) are biostimulants used to improve plant health. Efficacy of ANE and CHT was assessed individually and in combination against pea powdery mildew. Combined applications of ANE and CHT had a significant inhibitory effect on pathogen development and it reduced disease severity to 35%, as compared to control (90.5%). The combination of ANE and CHT enhanced the activity of plant defense enzymes; phenylalanine ammonia lyases (PAL), peroxidase (PO) and production of reactive oxygen species (ROS) and hydrogen peroxide (H2O2). Further, the treatment increased the expression of a number of plant defense genes in jasmonic acid (JA) signaling pathway such as LOX1 and COI and salicylic acid (SA)-mediated signaling pathway such as NPR1 and PR1. Other genes involved in defense mechanisms like NADPH oxidase and C4H were also upregulated by the combination treatment. The combination of ANE and CHT suppresses pea powdery mildew largely by modulating JA and SA-mediated signaling pathways.

中文翻译：

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结节提取物和壳聚糖的联合应用可协同激活豌豆抗白粉病的宿主防御能力

白粉病（PM）是豌豆的一种重要疾病，会降低产量。延寿菊提取物（ANE）和壳聚糖（CHT）是用于改善植物健康的生物刺激剂。单独和联合评估ANE和CHT对豌豆白粉病的功效。与对照（90.5％）相比，ANE和CHT的联合应用对病原体的生长具有显着的抑制作用，并将疾病严重程度降低至35％。ANE和CHT的结合提高了植物防御酶的活性；苯丙氨酸氨裂解酶（PAL），过氧化物酶（PO）以及活性氧（ROS）和过氧化氢（H2O2）的产生。进一步，该处理增加了茉莉酸（JA）信号通路（例如LOX1和COI）和水杨酸（SA）介导的信号通路（例如NPR1和PR1）中许多植物防御基因的表达。联合处理还上调了其他参与防御机制的基因，如NADPH氧化酶和C4H。ANE和CHT的组合在很大程度上通过调节JA和SA介导的信号通路来抑制豌豆白粉病。