Transcriptome and metabolome analyses reveal that Bacillus subtilis BS-Z15 lipopeptides mycosubtilin homologue mediates plant defense responses

Abstract

Microbial-plant interactions protect plants from external stimuli, releasing various elicitor that activate the plants defense response and regulate its growth. Bacillus subtilis BS-Z15 was screened from cotton inter-rhizosphere soil, antagonized various plant pathogens, and protected cotton against Verticillium dahliae. This study showed that the BS-Z15 lipopeptide mycosubtilin homologue could act as an elicitor to induce systemic resistance (ISR) in plants. Mycosubtilin homologue induced ROS burst and deposition, callose deposition, MAPK cascade phosphorylation, and up-regulated PR1 and PDF1.2 gene expression in Arabidopsis seedlings, moreover enhanced resistance of Arabidopsis to Pseudomonas syringae pv. Tomato DC3000 (Pst DC3000) and V. dahliae. Transcriptome analysis was then used to evaluate the impact of mycosubtilin homologue on plant gene expression control. Mycosubtilin homologues activated Arabidopsis ISR on genes in metabolic pathways such as Arabidopsis plant-pathogen interactions, phenylpropanoid biosynthesis, MAPK signaling pathway, and phytohormone signaling. These analyses revealed that mycosubtilin homologues mediate the regulation of plant systemic resistance and growth and development by affecting related metabolites in glycolysis and gluconeogenesis, pentose phosphate pathway, tricarboxylic acid cycle, and amino acid metabolism in Arabidopsis. These findings confirmed that a mycosubtilin homologue could trigger the initiation of the Arabidopsis ISR by interacting with a variety of PTI components and transcriptional metabolic signaling pathways.

Effect of bacillus subtilis strain Z15 secondary metabolites on immune function in mice

“…Bacillus subtilis is one of the main sources of probiotics and is classified as GRAS (Generally Recognized as Safe) by the US Food and Drug Administration (FDA). This organism has remarkable biosynthetic potential [ 6 ] and secretes a variety of secondary metabolites such as enzymes and lipopeptides that exhibit broad-spectrum antimicrobial [ 7 ], anticancer [ 8 ], antinematicidal activities [ 9 ], and immune activation in plants [ 10 ] and animals ( 11 – 13 ). Lipopeptides act as immunomodulators by interacting with pattern recognition receptors (PRRs), such as Toll-like receptors (TLRs), expressed on antigen-presenting cells (macrophages and dendritic cells) to activate immune functions [ 14 ].…”

“…In previous studies, secondary metabolites of B. subtilis strain Z15 (BS-Z15) were found to be highly effective as a broad-spectrum antibacterial in vitro and could act as an elicitor to regulate systemic resistance in plants by inducing the immune response of plants [ 10 ]. Furthermore, in vivo studies demonstrated that BS-Z15 was safe and non-toxic in animals.…”

Multigenerational Adaptation Can Enhance the Pathogen Resistance of Plants via Changes in Rhizosphere Microbial Community Assembly

“…57 Our results suggest that plants enhance their immunity by synthesizing these hormones. Yang et al 58 found that Bacillus subtilis BS-Z15 lipopeptides mycosubtilin homologue mediate plant immunity by activating the Arabidopsis ISR through multiple PTI components and transcriptional metabolic pathways (MAPK signaling pathway, phytohormone signaling, etc.). This suggests that bacterial communities can influence plant growth and immunity through certain pathways that regulate transcriptional metabolic pathways in plants.…”

Compatible Consortium of Endophytic Bacillus halotolerans Strains Cal.l.30 and Cal.f.4 Promotes Plant Growth and Induces Systemic Resistance against Botrytis cinerea

“…The ISR-eliciting activity of CFCF was attributed to Bacillus sp.-secreted metabolites with antibiotic functions, such as iturinic-type lipopeptides, iturin A and bacilomycin D, as well as to the lipopeptides fengycin and surfactin [ 55 ]. In particular, it has been demonstrated that the spraying of A. thaliana leaves with iturin A or mucosubtilin activated the expression of SA and JA defense-related genes, PR1 and PDF1.2 [ 56 ], while A. thaliana seedling treatment with mycosubtilin from B. subtilis J-15 activated the expression of ET and JA defense-related genes [ 57 ]. Similarly, root treatment of tomato plants with fengycin stimulated the induction of SA-responsive genes [ 58 ].…”