Bioprospection of Mammaliicoccus sciuri Strain TRQ48 as a Plant-Growth-Promoting Bacteria Associated with Wheat (Triticum turgidum L. subsp. durum) in the Yaqui Valley, Mexico

Klebsiella sp. IR6, an endophytic rhizobacteria with potential as a plant growth-promoting agent for Jalapeño pepper (Capsicum annum L.) production.

Plant growth-promoting rhizobacteria (PGPR) represent a sustainable alternative to reduce excessive agrochemical use and strengthen environmentally responsible agricultural practices. This study aimed to isolate, identify, and molecularly characterize endophytic bacteria associated with jalapeño pepper (Capsicum annuum L.) to evaluate their potential as PGPR and their antagonistic activity against phytopathogenic fungi. In vitro assays were conducted to determine functional traits related to plant growth promotion and biocontrol. Phylogenetic analysis identified the genera Stenotrophomonas, Pseudomonas, Paenibacillus, Klebsiella, Aeromonas, and Enterobacter. Among these isolates, Klebsiella sp. IR6 exhibited the most notable agronomic performance, increasing seedling leaf area (57%), fruit production (89%), and fruit size (15% in length and 31% in diameter) under field conditions. Additionally, IR6 was non-hemolytic, suggesting low risk to human health. This strain demonstrated antagonistic activity against Fusarium oxysporum (15-34%), siderophore production, and phosphate solubilization, confirming its potential as a biocontrol agent and PGPR. Transformation with plasmid pAD4325 carrying the GFP gene, followed by confocal microscopy, revealed its endophytic colonization within root tissues. Further evaluations using different jalapeño hybrids are necessary to validate the biotechnological potential of IR6 for sustainable agriculture.

A Promising Strain for Wheat Growth Promotion and Antifungal Activity Against Fungal Phytopathogens: Bacillus velezensis TRQ67

The rising global food demand requires boosting agricultural productivity without compromising environmental sustainability, especially in the face of intensive agrochemical use and soil degradation. Based on this, strain TRQ67 was isolated from wheat rhizosphere soil in the Yaqui Valley, Mexico, and characterized morphologically, biochemically, and genomically. Strain TRQ67 possesses a genome of 4.04 Mbp across 37 contigs with a G + C content of 46.3%, comprising 4127 coding DNA sequences (CDSs), and was identified as Bacillus velezensis through Overall Genome Relatedness Indices (OGRIs), including Average Nucleotide Identity (OrthoANI = 99.12%) and Genome-to-Genome Distance Calculator (Formula 2: 92.6%). The genome revealed key functional genes associated with auxin biosynthesis (trpABCDEF and yhcX), iron acquisition (dhbABF), nutrient solubilization (gabD, acnAB and pyc), stress response (clpCEPX and pspA), antifungal metabolite synthesis (srfAABCD, fenABCD and bmyABC), chemotaxis and motility (cheABCD, motAB, flgBCDEF, swrC), bacterial fitness (acoABR, acuABC and budABC), exopolysaccharide production (epsDEFHI), sporulation (spo0ABEF) and bioremediation. Predicted gene functions were supported by in vitro phenotypic assays; strain TRQ67 was able to solubilize phosphate (Solubilization Index of 4.1 ± 0.46), biosynthesize siderophores (Production Index of 1.70 ± 0.16), and produce indoles (6.52 ± 0.63 µg mL−1). Furthermore, this strain demonstrated antagonistic activity against phytopathogenic fungi Fusarium languescens and Bipolaris sorokiniana, resulting in reductions in fungal growth area of 87.33% and 89.28%, respectively. These antagonistic effects are consistent with the presence of Biosynthetic Gene Clusters (BGCs) encoding lipopeptides (surfactin and fengycin), polyketides (difficidin, bacillaene and macrolactin H), dipeptides (bacilysin) and siderophores (bacillibactin), as identified through antiSMASH analysis. Finally, the strain significantly improved root (27.63%) and shoot (5.82%) biomass in wheat plants under controlled conditions. These results highlight Bacillus velezensis TRQ67 as a promising microbial inoculant with plant growth promotion capabilities and potential antifungal activity against phytopathogenic fungi, as evidenced by strong in vitro antagonistic activity, supporting its further evaluation for sustainable agricultural practices.

Whole-genome sequencing and characterization of Pseudomonas stutzeri P1 endophyte isolated from potato unveils plant growth-promoting and other traits

Endophytic bacteria play an important role in plant growth promotion and stress tolerance, offering sustainable alternatives to chemical inputs in agriculture. In this study, an endophytic bacterial strain P1 was isolated and identified as Pseudomonas stutzeri , a plant-associated bacterium exhibiting multiple plant growth–promoting traits (PGPTs). Biochemical (qualitative and quantitative) and in vitro analyses demonstrated nitrogen fixation, phosphate solubilization, ammonia production, indole-3-acetic acid (IAA) production, biofilm formation, and tolerance to abiotic stresses, including salinity and drought. Furthermore, the P1 strain displayed strong biocontrol activity against the fungal pathogen Fusarium oxysporum f. sp. cumini, indicating its potential to mitigate biotic stress. Whole-genome sequencing generated a high-quality complete genome of 4,758,235 bp. Functional annotation showed enrichment of metabolic pathways associated with plant-microbe interactions and environmental adaptation. Further analyses using KEGG and PGPT-pred data confirmed the presence of genes associated with direct and indirect PGPT, such as nitrogen fixation, phosphate solubilization, biofilm formation, and stress tolerance. The genome also contained genes related to CAZymes, adhesion, and motility, highlighting a strong plant association, whereas the genome lacked major virulence factors and antimicrobial traits, supporting the non-pathogenic nature of the P1 strain. Overall, these findings demonstrate the potential of P1 as a promising bioinoculant candidate for sustainable agriculture in the potato sector.

Genomic insights into the bioremediation potential of Paenibacillus taichungensis strain 53b: a multi-resistant plant growth-promoting bacterium

Plant growth promotion of rice (Oryza sativa L.) with root endophytic bacteria, isolated from wild Solanaceous medicinal plants Solanum nigrum L., Solanum sisymbriifolium Lam., and Solanum virginianum L.

Pectobacterium aroidearum as a Causative Agent of Potato Soft Rot in China: Virulence Characterization and a Type 1 Fimbriae Cluster Contributing to Pathogenicity.

Soft rot Pectobacteriaceae (SRP) are destructive pathogens of potato crops, posing a global threat to food security. SRP populations exhibit significant genetic heterogeneity, with the prevalence of potato-infecting species shifting over time. In this study, we identified Pectobacterium aroidearum as a novel agent causing severe tuber soft rot in winter-planted potatoes in Guangdong Province, where it co-occurred with P. brasiliense and P. carotovorum. However, the pathogenic potential of P. aroidearum has been largely uncharacterized. Here, comparative virulence assays demonstrated that P. aroidearum is more aggressive than its counterparts. This heightened virulence was linked to enhanced pathogenic traits, including plant cell wall-degrading enzymes (PCWDEs) production, swimming motility, exopolysaccharide (EPS) production, and air-liquid (AL) biofilm formation. Genomic analysis revealed that while core virulence genes are conserved, a type 1 fimbriae-encoding fim cluster is unique to P. aroidearum. Deletion of fimA, fimC, fimD, and fimH impaired bacterial adhesion, EPS production, AL biofilm formation, and full virulence, functionally characterizing this distinctive factor. Genes within the bacterial cellulose synthesis operon were significantly down-regulated across fim mutants. Accordingly, the mutant colonies showed a marked decrease in calcofluor binding compared with the wild-type strain. Genes with significant up-regulation in the mutants were primarily involved in responses to extracellular stimuli. These findings indicate that the fim cluster underpins the threat posed by this emerging pathogen, which warrants increased attention in disease management. The considerable genetic diversity and frequent gene flow among P. aroidearum isolates from various hosts further highlight its epidemiological risk.