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Background and AimsDrug-induced liver injury (DILI) is a common cause of acute liver failure and represents a significant global public health problem. When discussing the gut-liver axis, although a great deal of research has focused on the role of gut microbiota in regulating the progression of DILI, the gut commensal fungal component has not yet been functionally identified.MethodsMice were pretreated with fluconazole (FC) to deplete the gut commensal fungi and were then subject to acetaminophen (APAP) gavage. In addition, transcriptome sequencing was performed to identify differentially expressed genes (DEGs) between control and fluconazole-pretreated groups of the mice challenged with APAP.ResultsGut commensal fungi ablation through fluconazole pretreatment predisposed mice to APAP-induced hepatotoxicity, characterized by elevated serum liver enzyme levels and more severe centrilobular necrosis, which appears to be caused by robust inflammation and oxidative stress. The 16S rDNA sequencing results indicated that Akkermansia muciniphila abundance had significantly decreased in gut fungi-depleted mice, whereas increased abundance of Helicobacter rodentium was observed. The gene interaction network between DEGs identified by the transcriptome sequencing highlighted a significant enrichment of Cyp2a5 in the liver of APAP-treated mice that were preadministrated with fluconazole. Pharmacological inhibition of Cyp2a5 by 8-methoxypsoralen (8-MOP) could significantly attenuate hepatic inflammation and oxidative stress in mice, thereby conferring resistance to acute liver injury caused by APAP administration.ConclusionOur data highlighted the significance of gut commensal fungi in hepatic inflammation and oxidative stress of APAP mice, shedding light on promising therapeutic strategies targeting Cyp2a5 for DILI treatment.

Drought stress represents a major constraint with significant impacts on wheat crop globally. The use of plant growth-promoting bacteria (PGPB) has emerged as a promising strategy to alleviate the detrimental impacts of water stress and enhance plant development. We investigated 24 strains from diverse ecosystems, assessed for PGP traits and tolerance ability to abiotic stresses (drought, salinity, temperature, pH, heavy metals, pollutants, herbicides, and fungicides). The most effective bacterial strains Providencia vermicola ME1, Pantoea agglomerans Pa, Pseudomonas knackmussi MR6, and Bacillus sp D13 were chosen. Furthermore, these strains exhibited PGP activities under osmotic stress (0, 10, 20, and 30% PEG-6000). The impact of these osmotolerant PGPBs on wheat (Triticum durum L.) growth under drought stress was assessed at two plant growth stages. In an in vitro wheat seed germination experiment, bacterial inoculation significantly enhanced germination parameters. In pot experiments, the potential of these bacteria was evaluated in wheat plants under three treatments: Well-watered (100% field capacity), moderate stress (50% FC), and severe stress (25% FC). Results showed a significant decline in wheat growth parameters under increasing water stress for uninoculated seedlings. In contrast, bacterial inoculation mitigated these adverse effects, significantly improving morphological parameters and chlorophyll pigment contents under the stress conditions. While malondialdehyde (lipid peroxidation) and proline contents increased significantly with drought intensity, they decreased after bacterial inoculation. The antioxidant enzyme activities (GPX, CAT, and SOD) in plants decreased after bacterial inoculation. The increased root colonization capacity observed under water stress was attributed to their ability to favorable adaptations in a stressful environment. This study highlighted the potential of selected PGPB to alleviate water stress effects on wheat, promoting practical applications aimed at enhancing crop resilience under conditions of water shortage.

Among plant disease management strategies, biological control is a sustainable alternative to the use of chemicals for the control of vascular wilt caused by Fusarium oxysporum. Fusarium wilt is the most devastating disease affecting a wide variety of plants. Bacillus species are the most widely used biological control candidates for the control of these fungal diseases. This review describes the pathogenicity of F. oxysporum, its virulence mechanisms, and host plant–pathogen interactions. The control means deployed by Bacillus species inhibit or kill these phytopathogens. Bacillus spp. produce a wide range of secondary metabolites, including volatile and non-volatile organic compounds. Biocontrol potential is achieved through direct antimicrobial activity, the induction of the host plant’s immune response (Induced Systemic Resistance), and competition for nutrients and space. In addition, parameters governing the selection of effective biocontrol agents and their survival in plant microbial communities are discussed. The influence of the microbiota on the establishment and development of biocontrol agents can assess the potential of these treatments and facilitate the development of effective biopesticides during their field application.

Plant disease outbreaks are increasingly exacerbated by climate change and the conditions of stress combinations. They are negatively affecting crop yield and driving threats to food security in many areas of the world. Although synthetic pesticides offer relative success in the control of pests and plant diseases, they are often overused, and this method faces numerous drawbacks, including environmental toxicity, soil degradation, and adverse effects on human health. Therefore, alternatives are being developed and examined, including the biocontrol of pests and pathogens and biomass pyrolysis leading to wood vinegar that has shown great promise in agriculture and organic farming. However, while wood vinegar use is expanding and allows the control of numerous pests and bacterial and fungal diseases, its application to control oomycete diseases is limited. This study aimed to test wood vinegar for the control of oomycete plant pathogens from which six wood vinegars of pistachio, pomegranate, almond, pine, cypress, and walnut were produced. The inhibitory effects of volatile metabolites (semi-VOCs) of different wood vinegars concentrations (100%, 50%, 25%, 12.5%, and 6.25%) were examined against the hyphal growth of Globisporangium ultimum and Pythium aphanidermatum isolates. An in vitro analysis unambiguously demonstrated that for Globisporangium ultimum, the wood vinegar semi-VOCs of almond, pistachio (C 100% and 50%), and walnut (C 100%) totally inhibited mycelial growth. On the other hand, Pythium aphanidermatum, pistachio (C 100%, 50%, and 25%), and cypress (C 100%) expressed their abilities to completely inhibit the mycelial growth. Other treatments, including relevant concentrations of pine and pomegranate significantly inhibited the growth of mycelia of both species compared to the control (p ≤ 0.05). Therefore, wood vinegar could be considered a natural and organic product to use in agriculture to cope not only against pests, bacterial and fungal pests but also against emerging oomycete plant diseases.

Date palm (Phoenix dactylifera L.) plantations in North Africa are nowadays threatened with the spread of the Bayoud disease caused by Fusarium oxysporum f. sp. albedinis, already responsible for destroying date production in other infected areas, mainly in Morocco. Biological control holds great promise for sustainable and environmental-friendly management of the disease. In this study, the additional benefits to agricultural ecosystems of using plant growth promoting rhizobacteria (PGPR) or endophytes are addressed. First, PGPR or endophytes can offer an interesting bio-fertilization, meaning that it can add another layer to the sustainability of the approach. Additionally, screening of contrasting niches can yield bacterial actors that could represent wardens against whole genera or groups of plant pathogenic agents thriving in semi-arid to arid ecosystems. Using this strategy, we recovered four bacterial isolates, designated BFOA1, BFOA2, BFOA3 and BFOA4, that proved very active against F. oxysporum f. sp. albedinis. BFOA1–BFOA4 proved also active against 16 Fusarium isolates belonging to four species: F. oxysporum (with strains phytopathogenic of Olea europaea and tomato), F. solani (with different strains attacking O. europaea and potato), F. acuminatum (pathogenic on O. europaea) and F. chlamydosporum (phytopathogenic of O. europaea). BFOA1–BFOA4 bacterial isolates exhibited strong activities against another four major phytopathogens: Botrytis cinerea, Alternaria alternata, Phytophthora infestans, and Rhizoctonia bataticola. Isolates BFOA1–BFOA4 had the ability to grow at temperatures up to 35°C, pH range of 5–10, and tolerate high concentrations of NaCl and up to 30% PEG. The isolates also showed relevant direct and indirect PGP features, including growth on nitrogen-free medium, phosphate solubilization and auxin biosynthesis, as well as resistance to metal and xenobiotic stress. Phylogenomic analysis of BFOA1–BFOA4 isolates indicated that they all belong to Bacillus halotolerans, which could therefore considered as a warden against Fusarium infection in plants. Comparative genomics allowed us to functionally describe the open pan genome of B. halotolerans and LC-HRMS and GCMS analyses, enabling the description of diverse secondary metabolites including pulegone, 2-undecanone, and germacrene D, with important antimicrobial and insecticidal properties. In conclusion, B. halotolerans could be used as an efficient bio-fertilizer and bio-control agent in semi-arid and arid ecosystems.

The Gram positive, non-pathogenic endospore-forming soil inhabiting prokaryote Bacillus amyloliquefaciens is a plant growth-promoting rhizobacterium. Bacillus amyloliquefaciens processes wide biocontrol abilities and numerous strains have been reported to suppress diverse bacterial, fungal and fungal-like pathogens. Knowledge about strain level biocontrol abilities is warranted to translate this knowledge into developing more efficient biocontrol agents and bio-fertilizers. Ever-expanding genome studies of B. amyloliquefaciens are showing tremendous increase in strain-specific new secondary metabolite clusters which play key roles in the suppression of pathogens and plant growth promotion. In this report, we have used genome mining of all sequenced B. amyloliquefaciens genomes to highlight species boundaries, the diverse strategies used by different strains to promote plant growth and the diversity of their secondary metabolites. Genome composition of the targeted strains suggest regions of genomic plasticity that shape the structure and function of these genomes and govern strain adaptation to different niches. Our results indicated that B. amyloliquefaciens: (i) suffer taxonomic imprecision that blurs the debate over inter-strain genome diversity and dynamics, (ii) have diverse strategies to promote plant growth and development, (iii) have an unlocked, yet to be delimited impressive arsenal of secondary metabolites and products, (iv) have large number of so-called orphan gene clusters, i.e., biosynthetic clusters for which the corresponding metabolites are yet unknown, and (v) have a dynamic pan genome with a secondary metabolite rich accessory genome.