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Grapevine trunk diseases (GTDs), particularly Esca, represent a major challenge for viticulture worldwide, leading to substantial economic losses. With no effective control treatments available, developing new methods such as biocontrol is crucial for managing GTDs. Our aim was to select biocontrol bacteria effective against the white-rot fungal pathogen Fomitiporia mediterranea (Fmed) and to investigate their mechanisms of action. A stepwise screening of 58 bacterial strains was conducted in vitro to assess their ability to inhibit Fmed growth through volatile and diffusible metabolites production. The screening was also done on wood sawdust from seven different grapevine cultivars. Out of 58 tested strains, 49 inhibited Fmed growth by over 50 % through their volatile organic compounds, only eight achieving this through their agar-diffusible metabolites. Pseudomonas lactis SV9, Pseudomonas paracarnis S45, and Paenibacillus polymyxa SV13 exhibited a strong efficacy in inhibiting Fmed on wood sawdust in a cultivar-dependent manner. We selected these strains for whole genome analysis and metabolomic profiling via LC-MS/MS for diffusible compounds and SPME GC-MS for volatile compounds. P. polymyxa SV13 inhibited Fmed primarily through diffusible metabolites, producing mainly fusaricidin-type compounds. Conversely, Pseudomonas strains acted mainly via their volatile metabolites, producing mainly the antifungal compound dimethyl disulfide. Genome analysis of the three bacterial strains revealed gene clusters responsible for regulating both direct and indirect mechanisms in biocontrol agents (BCAs). Our findings highlight the importance of comprehensive studies that combine in vitro experiments mimicking field conditions, with detailed investigations into modes of action to improve BCAs efficacy., (Copyright © 2025 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Background: Vitamin B 12 (cobalamin) can be produced de novo only by certain bacteria and archaea. It plays a crucial role in the health of animals and humans, which obtain it only through diet, mainly from animal products. This study aimed to identify endophytic bacterial strains capable of synthesizing vitamin B 12 and enriching edible plants with it as a potential solution for vitamin B 12 deficiency in vegetarians, vegans, and people with poor diets., Results: An in silico genome analysis was performed on 66 bacterial genomes, including the reference strain Pseudomonas denitrificans ATCC 13867, a known vitamin B 12 producer. The genomes were analyzed using the Rapid Annotations using Subsystems Technology (RAST) server and the MetaCyc database to verify the presence and completeness of the vitamin B 12 metabolic pathway. The ability of the strains to produce vitamin B 12 was confirmed with a high-performance liquid chromatography with diode-array detection (HPLC-DAD) analysis of pure culture extracts. Eleven strains produced detectable amounts of vitamin B 12 under tested conditions. The best performing candidates were further tested for their efficacy in producing vitamin B 12 in lettuce grown under sterile conditions on Murashige and Skoog (MS) medium with or without CoCl 2 supplementation. Methylobacterium sp. strain P1-11 produced detectable amounts of vitamin B 12 in planta: 1.654 and 2.559 μg per g of dry weight without and with CoCl 2 supplementation, respectively., Conclusion: This is the first time a bacterial endophyte was used to produce vitamin B 12 in planta, suggesting that bacterial endophytes could be utilized to enhance the nutraceutical values of plant-based foods. © 2025 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry., (© 2025 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.)

Background: Paenibacillus polymyxa is a bacterial species of high interest, as suggested by the increased number of publications on its functions in the past years. Accordingly, the number of described strains and sequenced genomes is also on the rise. While functional diversity of P. polymyxa has been suggested before, the available genomic data is now sufficient for robust comparative genomics analyses., Results: Using 157 genomes, we found significant disparities among strains currently affiliated to P. polymyxa. Multiple taxonomic groups were identified with conserved predicted functions putatively impacting their respective ecology. As strains of this species have been reported to exhibit considerable potential in agriculture, medicine, and bioremediation, it is preferable to clarify their taxonomic organization to facilitate reliable and durable approval as active ingredients., Conclusions: Strains currently affiliated to P. polymyxa can be separated into two major species groups with differential potential in nitrogen fixation, plant interaction, secondary metabolism, and antimicrobial resistance, as inferred from genomic data., (© 2024. The Author(s).)

Ascomycetes, basidiomycetes and deuteromycetes can degrade wood, but less attention has been paid to basidiomycetes involved in Esca, a major Grapevine Trunk Disease. Using a wood sawdust microcosm system, we compared the wood degradation of three grapevine cultivars inoculated with Fomitiporia mediterranea M. Fisch, a basidiomycete responsible for white-rot development and involved in Esca disease. The grapevine cultivar Ugni blanc was more susceptible to wood degradation caused by F. mediterranea than the cultivars Cabernet Sauvignon and Merlot. Solid-state Nuclear Magnetic Resonance (NMR) spectroscopy showed that F. mediterranea preferentially degrades lignin and hemicellulose over cellulose (preferential, successive or sequential white-rot). In addition, co-inoculation of sawdust with two cellulolytic and xylanolytic bacterial strains of Paenibacillus (Nakamura) Ash (Paenibacillus sp. (S231-2) and P. amylolyticus (S293)), enhanced F. mediterranea ability to degrade Ugni blanc. The NMR data further showed that the increase in Ugni blanc sawdust degradation products was greater when bacteria and fungi were inoculated together. We also demonstrated that these two bacterial strains could degrade the wood components of Ugni blanc sawdust. Genome analysis of these bacterial strains revealed numerous genes predicted to be involved in cellulose, hemicellulose, and lignin degradation, as well as several other genes related to bacteria-fungi interactions and endophytism inside the plant. The occurrence of this type of bacteria-fungus interaction could explain, at least in part, why necrosis develops extensively in certain grapevine varieties such as Ugni blanc., (© 2024. The Author(s).)

Improved understanding of the complex interaction between plant metabolism, environmental conditions and the plant-associated microbiome requires an interdisciplinary approach: Our hypothesis in our multiomics study posited that several environmental and biotic factors have modulating effects on the microbiome and metabolome of the roots of wild Echium vulgare plants. Furthermore, we postulated reciprocal interactions between the root metabolome and microbiome. We investigated the metabolic content, the genetic variability, and the prokaryotic microbiome in the root systems of wild E. vulgare plants at rosette and flowering stages across six distinct locations. We incorporated the assessment of soil microbiomes and the measurement of selected soil chemical composition factors. Two distinct genetic clusters were determined based on microsatellite analysis without a consistent alignment with the geographical proximity between the locations. The microbial diversity of both the roots of E. vulgare and the surrounding bulk soil exhibited significant divergence across locations, varying soil pH characteristics, and within the identified plant genetic clusters. Notably, acidophilic bacteria were characteristic inhabitants of both soil and roots under acidic soil conditions, emphasizing the close interconnectedness between these compartments. The metabolome of E. vulgare significantly differed between root samples from different developmental stages, geographical locations, and soil pH levels. The developmental stage was the dominant driver of metabolome changes, with significantly higher concentrations of sugars, pyrrolizidine alkaloids, and some of their precursors in rosette stage plant roots. Our study featured the complex dynamics between soil pH, plant development, geographical locations, plant genetics, plant metabolome and microbiome, shedding light on existing knowledge gaps., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Csorba, Rodić, Antonielli, Sessitsch, Vlachou, Ahmad, Compant, Puschenreiter, Molin, Assimopoulou and Brader.)

The order Isopoda contains both aquatic and terrestrial species, among which Hemilepistus reaumurii, which lives in arid environments and is the most adapted to terrestrial life. Olfaction has been deeply investigated in insects while it has received very limited attention in other arthropods, particularly in terrestrial crustaceans. In insects, soluble proteins belonging to two main families, Odorant Binding Proteins (OBPs) and Chemosensory Proteins (CSPs), are contained in the olfactory sensillar lymph and are suggested to act as carriers of hydrophobic semiochemicals to or from membrane-bound olfactory receptors. Other protein families, namely Nieman-Pick type 2 (NPC2) and Lipocalins (LCNs) have been also reported as putative odorant carriers in insects and other arthropod clades. In this study, we have sequenced and analysed the transcriptomes of antennae and of the first pair of legs of H. reaumurii focusing on soluble olfactory proteins. Interestingly, we have found 13 genes encoding CSPs, whose sequences differ from those of the other arthropod clades, including non-isopod crustaceans, for the presence of two additional cysteine residues, besides the four conserved ones. Binding assays on two of these proteins showed strong affinities for fatty acids and long-chain unsaturated esters and aldehydes, putative semiochemicals for this species., Competing Interests: Conflicts of interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)