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

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

Bioprospecting of plant growth-promoting bacteria enables the identification of beneficial microbial resources with significant potential for sustainable agricultural applications. In this context, strain TRQ48 was isolated from a commercial field of wheat (Triticum turgidum L. subsp. durum) located in the Yaqui Valley, Mexico, with the aim of exploring its plant growth-promoting potential. The draft genome sequence presented a genomic size of 2,777,016 bp, 32.5% G + C content, 665,763 bp N50, 2 L50, and 19 contigs. Taxonomic affiliation demonstrated that strain TRQ48 belonged to Mammaliicoccus sciuri. Genome annotation identified 2756 coding DNA sequences (CDS) distributed into 259 subsystems, highlighting CDS associated with iron acquisition and metabolism, stress response, and virulence, disease, and defense, among others. Metabolic assays reflect the strain’s capacity to produce siderophores and auxins, relating these positive traits to significantly (p ≤ 0.05) promote growth of wheat shoot length (7.09%) and root and shoot dry weight (75% and 18.43%) compared to uninoculated wheat plants. Biosafety testing indicated that the strain is susceptible to commonly used antibiotics and lacks clinically relevant resistance profiles, matching genomic analysis, which did not reveal any critical virulence factors. Thus, although the presented results show that M. sciuri TRQ48 is a promising beneficial biosafe strain, further studies are still needed to evaluate its performance under agro-ecosystems at commercial levels.

Taxonomy, Biological Characterization, and Fungicide Sensitivity of a New Species, Cladobotryum hypsigum, Causing Cobweb Disease in Gold Mushroom (Pholiota conissans) in China.

In vitro fungicide sensitivity assays, performed using the hyphal growth inhibition method against six common fungicides, demonstrated that Carbendazim was the most effective agent, indicating significant selectivity.

Molecular identification, pathogenicity assessment, and cellulase and protease production of fungi associated with root rot of cowpea (Vigna unguiculata L.)

Cowpea (Vigna unguiculata L.) is a major grain legume whose productivity is severely limited by soil-borne root rot pathogens. This study isolated and identified the fungi associated with cowpea root rot and evaluated their pathogenicity and extracellular enzyme production. A total of 45 fungal isolates were recovered from naturally infected cowpea roots and identified as Fusarium solani, Fusarium oxysporum, Rhizoctonia solani, and Macrophomina phaseolina. F. solani was the predominant species, accounting for 33.33% of the isolates. Morphological identification was confirmed by ITS-rDNA sequencing, and the representative F. solani isolate was deposited in GenBank under accession number LC924504. Pathogenicity assays demonstrated significant differences among the tested fungi. F. solani exhibited the greatest virulence, reducing seed germination to 20% in the Petri dish assay and causing 100% disease incidence with a mean disease severity of 79.17% under greenhouse conditions. F. oxysporum ranked second in pathogenicity, whereas R. solani and M. phaseolina were comparatively less aggressive. Enzymatic analyses revealed that F. solani produced the highest cellulase (2.08 U mL-1) and protease (5.09 U mL-1) activities, indicating a strong association between extracellular hydrolytic enzyme production and fungal virulence. The elevated enzymatic activity corresponded closely with increased disease incidence, disease severity, and reduced seed germination. Overall, the findings identify F. solani as the principal causal agent of cowpea root rot and highlight the critical role of cell wall-degrading enzymes in disease development. These results provide a basis for developing effective disease management strategies and breeding resistant cowpea cultivars.

Pectobacterium nicotianae sp. nov., a novel pathogen causing tobacco hollow stalk disease, is phylogenetically distinct from P. brasiliense

Five Gram-negative, facultatively anaerobic bacteria were isolated from the hollow stalk tissues of tobacco plants in Yunnan, China. Based on polyphasic taxonomic data, they were identified as a new Pectobacterium species. Phylogenetic analyses of 16S rRNA and the concatenated dnaX-leuS-recA genes grouped them into a distinct monophyletic clade. Genome analyses showed high average nucleotide identity (ANIb 96.96–97.63%) and digital DNA-DNA hybridization (dDDH 76.2–80.1%) values, supporting their classification as a single species. However, three indices, including lower dDDH (67.9%), borderline ANIb (95.89%), and phylogenomic separation with 99% support, differentiate them from Pectobacterium brasiliense IPO 3540T. Comparative genomics across 24 reference strains revealed differences in virulence factors and specific plant cell wall-degrading enzyme profiles, highlighting adaptations to different hosts. Biochemical tests showed that all isolates lacked β-glucosidase and exhibited unique carbon utilization patterns; chemotaxonomically, strain 21LCBS03T produced only menaquinone MK-8. Pathogenicity experiments confirmed that four strains caused severe soft rot and hypersensitive responses on various hosts, while strain BSHS4, with a dDDH of 76.2% relative to 21LCBS03T, showed reduced virulence—possibly a subspecies. Reanalysis of 633 Pectobacterium genomes from NCBI reclassified 121 strains into this new species, exposed common misidentifications, and identified 9 candidate novel species awaiting phenotypic validation. Combining phylogenomic, virulence, phenotypic, and pathogenic data, we propose Pectobacterium nicotianae sp. nov., with 21LCBS03T (=GDMCC 1.3317T = CCTCC AB2022131T = JCM 35650T) designated as the type strain.

Genome based characterization of an endophytic Bacillus subtilis BS01 associated with suppression of Fusarium wilt in Cavendish banana caused by Fusarium oxysporum f. sp. cubense Tropical Race 4

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

IR6 exhibited the most notable agronomic performance, increasing seedling leaf area, fruit production, and fruit size under field conditions and demonstrating antagonistic activity against Fusarium oxysporum, confirming its potential as a biocontrol agent and PGPR.