Animal-Plant Interactions Lab, Department of Zoology, Sri Venkateswara College, University of Delhi, Dhaula Kuan, New Delhi 110021, India.
FEMS Microbiol Ecol. 2020 Apr 1;96(4). doi: 10.1093/femsec/fiaa040.
Microbial fertilizers have increasingly gained popularity as environmentally sustainable nutritional supplement for plant growth. However, the effect of these microbes on plant-induced responses and the resultant effect on late-arriving herbivores are still unclear. Following insect herbivory, oxidative stress is one of the earliest responses induced in plants. Therefore, we analyzed the effect of phosphorus solubilizing bacteria (PSB), vesicular-arbuscular mycorrhiza (VAM) and their combination on oxidative stress in Brassica juncea against Spodoptera litura herbivory. Six antioxidant enzymes, viz. superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), monodehydroascorbate reductase and glutathione reductase (GR), were studied. Our results indicated a sporadic increase of APX and GR in PSB-supplemented plants. In contrast, VAM-supplemented plants showed an active systemic response against herbivory with an increase in all the six enzymes at 72 h. Conversely, supplementation of PSB-VAM together led to increased APX, SOD, CAT and POD enzymes, which subsided by 72 h. Thus, the presence of VAM, alone or in combination with PSB, acted like a vaccination for plants against stress. However, the mode of action of PSB and VAM governed the temporal dynamics of antioxidants. Our study thus shows microbial fertilizers have prominent effects on plant immunity.
微生物肥料作为一种对环境可持续的植物生长营养补充越来越受到欢迎。然而，这些微生物对植物诱导反应的影响以及对后来的草食性动物的影响尚不清楚。在昆虫取食后，氧化应激是植物最早诱导的反应之一。因此，我们分析了解磷细菌（PSB）、泡囊丛枝菌根（VAM）及其组合对芥菜（Brassica juncea）对斜纹夜蛾（Spodoptera litura）取食的氧化应激的影响。研究了 6 种抗氧化酶，即超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）、抗坏血酸过氧化物酶（APX）、单脱氢抗坏血酸还原酶和谷胱甘肽还原酶（GR）。结果表明，添加 PSB 的植物中 APX 和 GR 呈零星增加。相比之下，添加 VAM 的植物对取食表现出积极的系统反应，所有 6 种酶在 72 小时时均增加。相反，同时添加 PSB-VAM 会导致 APX、SOD、CAT 和 POD 酶的增加，72 小时后这些酶的含量下降。因此，VAM 的存在，无论是单独存在还是与 PSB 一起存在，都能像给植物接种疫苗一样，使植物免受应激。然而，PSB 和 VAM 的作用方式控制了抗氧化剂的时间动态。因此，我们的研究表明，微生物肥料对植物的免疫有显著的影响。
