Bacillus amyloliquefaciens PMB05 Increases Resistance to Bacterial Wilt by Activating Mitogen-Activated Protein Kinase and Reactive Oxygen Species Pathway Crosstalk in Arabidopsis thaliana

Abstract

Bacterial wilt caused by Ralstonia solanacearum can infect many crops, causing significant losses worldwide. The use of beneficial microorganisms is considered a feasible method for controlling this disease. Our previous study showed that Bacillus amyloliquefaciens PMB05 can control bacterial wilt through intensifying immune signals triggered by a pathogen-associated molecular pattern (PAMP) from R. solanacearum. It is still uncertain whether induction of the mitogen-activated protein kinase (MAPK) pathway during PAMP-triggered immunity (PTI) is responsible for enhancing disease resistance. To gain more insights on how the presence of PMB05 regulates PTI signaling, its association with the MAPK pathway was assayed. Our results showed that the activation of MPK3/6 and expression of wrky22 upon treatment with the PAMP, PopW, was increased during co-treatment with PMB05. Moreover, the disease resistance conferred by PMB05 to bacterial wilt was abolished in mekk1, mkk5, and mpk6 mutants. To determine the relationship between the MAPK pathway and plant immune signals, the assay on reactive oxygen species (ROS) generation and callose deposition showed that only the ROS generation was strongly reduced in these mutants. Because ROS generation is highly correlated with RbohD, the results revealed that the effects of PMB05 on both PopW-induced ROS generation and disease resistance to bacterial wilt were eliminated in the rbohD mutant, suggesting that the generation of ROS is also required for PMB05-enhanced disease resistance. Taken together, we concluded that the crosstalk between the initiation of ROS generation and further activation of the MAPK pathway is necessary when PMB05 is used to improve disease resistance to bacterial wilt. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Cyclic Lipopeptides of Bacillus amyloliquefaciens DHA6 Are the Determinants to Suppress Watermelon Fusarium Wilt by Direct Antifungal Activity and Host Defense Modulation

“…The plant immune system is believed to rely on coordinated signaling pathways, including SA, JA, and ET pathways, to mount an effective defense response against pathogen attack [ 12 ]. Bacillus -primed ISR has been shown to involve the JA/ET and SA signaling pathways and multiple early signaling events, such as MAPK cascades and ROS [ 26 , 28 , 74 , 75 , 76 , 77 ]. In lettuce, B. amyloliquefaciens FZB42-produced surfactin, and other immunomodulatory CLPs triggered immunity against R. solani by inducing the expression of defense-related genes, including LsPDF1.2 , LsPR1, and LsLOX [ 28 ], while fusaricidin, purified from Paenibacillus polymyxa WLY78, induced SA-specific ISR to suppress Fusarium wilt in cucumber [ 78 ].…”

Genome-wide analysis of Respiratory burst oxidase homolog (Rboh) genes inAquilariaspecies and its association with agarwood formation

“…Recent research on similar line suggested ROS mediated activation of MAPK pathway during plant-pathogen interaction (Pacheco-Trejo et al, 2022;Chuang et al, 2022). Interestingly, in other plants as well, Rboh have been shown to be involved in responses to microbial infection (Morales et al, 2016, Chaung et al, 2022.…”

Developing Fermentation Liquid of Bacillus amyloliquefaciens PMB04 to Control Bacterial Leaf Spot of Sweet Pepper

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