Aug 2026· Microorganisms· Vol 14· 0 citations· 51 references
Medicine
TL;DR
The results suggest that facing continuously increased environmental stress over time, GHZJ-1 undergoes global transcriptional reprogramming and resource reallocation, downregulating basal metabolism to construct a synergistic antagonistic system coupling chemical defense with nutritional competition.
Abstract
Frequent outbreaks of bacterial and fungal diseases in aquaculture cause severe economic losses, making biological control using probiotics a crucial strategy. Bacillus velezensis synthesizes diverse antimicrobial secondary metabolites; however, its biocontrol potential is tightly regulated by environmental signals such as cultivation time. In this study, we investigated the effect of growing time on the antifungal activity of B. velezensis GHZJ-1, isolated from an aquatic environment. It was found that GHZJ-1 shows obvious antifungal activity against the aquatic pathogen Metschnikowia bicuspidata upon 48 h growth but no such activity for 24 h via the agar-diffusion method. We further compared the transcriptomes of GHZJ-1 cells collected at 24 h and 48 h through RNA-Seq. Our results revealed that compared with 24 h, 1821 genes were differentially expressed at 48 h, with 903 upregulated and 918 downregulated. Downregulated genes were enriched in primary metabolic pathways (e.g., ribosome assembly and carbon metabolism), whereas upregulated genes were enriched in secondary metabolite biosynthesis and transmembrane transport. Importantly, 35 upregulated genes directly associated with antimicrobial activity were identified, notably including the ones encoding core elements of a large polyketide synthase (e.g., pksN, log2FC = 2.24), the petrobactin siderophore system (highest log2FC = 3.39), and various antimicrobial peptide export systems. Furthermore, the degU gene was activated at 48 h. These data suggest that facing continuously increased environmental stress over time, GHZJ-1 undergoes global transcriptional reprogramming and resource reallocation, downregulating basal metabolism to construct a synergistic antagonistic system coupling chemical defense with nutritional competition. This study elucidates the time-dependent mechanism for antifungal activity in GHZJ-1, providing a molecular theoretical basis for its green biocontrol application in aquaculture diseases caused by fungi.
Microorganisms of the crop rhizosphere are essential for maintaining crop health. Corn root rot (CRR) caused by Fusarium oxysporum is a severe disease that affects global maize yield and food security. Maize recruits beneficial rhizosphere microorganisms to resist F. oxysporum; however, the mechanism underlying this recruitment remains poorly understood. Here, we performed multi-omics analyses and experimental validation to investigate the microbial community in F. oxysporum-invaded maize roots. Maize-enriched Bacillus velezensis in the rhizosphere alleviated pathogenic stress by inhibiting F. oxysporum growth primarily through the direct production of antimicrobial metabolites that disrupted the pathogen's cellular structure. We elucidated the antimicrobial mechanism of the cell-free supernatant (CFS) by performing multi-omics analyses and validation. As CFS treatment duration increased, the pathogenic metabolic disorder intensified, and metabolic homeostasis of the genetic material showed increased disruption owing to interference of RNA processing and transcription. Additionally, the expression of pathogenicity-related genes NR1, STUA, and FOW was significantly downregulated. The key antimicrobial components comprised non-volatile metabolites (NVMs) of the benzenoid class (e.g., 4-Hydroxybenzaldehyde) and volatile metabolites (VOCs) of the alcohol and ketone classes (e.g., 5-methyl-2-heptanol) in the CFS. All compounds exhibited broad-spectrum antimicrobial activity. Thus, these results clarify the ecological strategy underlying the recruitment of beneficial B. velezensis in the rhizosphere of maize to resist F. oxysporum invasion, and they elucidate the specific antimicrobial mechanism of Bacillus. Notably, these findings provide an important foundation for future green prevention and control of soil-borne pathogens.
Root-knot nematodes (
Meloidogyne
spp.) are devastating plant pathogens that cause substantial economic losses worldwide. This study uses RNA-seq to profile the transcriptomic responses of
M. incognita
to the culture supernatant of
Streptomyces
sp. TR27, a strain previously shown to induce 67.6% calibrated mortality against
M. incognita
second-stage juveniles at 48 h. At 12 h post treatment, 231 differentially expressed genes (DEG) were identified, including 114 up-regulated and 117 down-regulated genes. Down-regulated genes were enriched in the pathways related to lysosome (lysosomal ATPase, acid hydrolase, and membrane protein) and steroid hormone metabolism. Gene set enrichment analysis (GSEA) further revealed the transcriptional suppression of oxidative phosphorylation (Complexes I-V) and ribosomal protein coding genes at 12 h post treatment. These findings suggest that the
Streptomyces
sp. TR27 supernatant is associated with multi-pathway transcriptional perturbations, including lysosomal homeostasis dysregulation, steroid hormone metabolism impairment, and potential inhibition of mitochondrial energy production and protein translation. This transcriptional signature provides candidate cellular targets and a hypothetical framework for developing actinobacteria-derived biocontrol agents, pending functional validation of direct compound-target interactions.
Ling Qu, R. Han, Z. Rao et al.· Nematology· 0 citations
The present study is the first to report the antifungal activity of bacillopeptins against Sclerotinia sclerotiorum, a fungus responsible for white mold.
Maria Luiza A. Jesus-Nicoletto, J. P. Baptista, S. Noriler et al.· Scientific Reports· 1 citation
These findings provide the first comprehensive evidence that alkaloid metabolism, particularly the isoquinoline alkaloid pathway, are transcriptionally and metabolically reprogrammed during blister blight infection, suggesting a potential role in tea’s defense against this pathogen.
Yanglongyu Chen, Ping Li, Yuqing Ma et al.· Frontiers in Plant Science· 0 citations
The investigated crude extract exhibited pronounced antitumor activity, making it a promising candidate for further studies, and the underlying hypothesis suggested that strains with broad adaptive potential may serve as promising producers of natural products with antitumor properties.
Andrii Sylchuk, M. Loboda, Ivan Roman et al.· Applied Sciences· 0 citations