Fuente: PubMed "Tobacco production" BMC Microbiol. 2025 Nov 25;25(1):775. doi: 10.1186/s12866-025-04485-4.ABSTRACTTobacco bacterial wilt, caused by Ralstonia solanacearum species complex (RSSC), poses a significant threat to tobacco production in most major tobacco-growing regions of China. Here, 204 strains of Ralstonia were isolated from infected tobacco plants across 12 provinces and autonomous regions in China. Molecular identification and biovar typing of the RSSC strains revealed that all the isolates were found in phylotype I (classified as R. pseudosolanacearum) and biovar III. Seven sequevars were identified and sequevar 15 was the most prevalent. Pathogenicity tests indicated that 29% of the strains showing high virulence were found in the southwest tobacco-growing region of China. Notably, significant pathogenic variation was observed within strains of the same sequevar, and no clear correlation was found between the sequevar type and pathogenicity. Using Oxford Nanopore sequencing, we analyzed 103 strains of tobacco R. pseudosolanacearum from different geographical origins and pathotypes. The pangenome of R. pseudosolanacearum is comprised of 9008 non-redundant genes, divided into a core genome (36%), accessory genome (48.7%) and isolate-specific genes (15%). Core genome functions were related to oxidation–reduction reaction process and DNA transcription regulation, while the accessory genome was linked to DNA recombination, integration, and transposition. SNP analysis revealed an average of 36,740 SNP loci per strain, indicating evolutionary purification with ka/ks value below 1. Phylogenetic analysis divided 99 strains into 4 main groups, with sequevars correlated to specific branches, reflecting evolutionary relationships. We identified 2226 genomic islands across the strains, with each strain containing 18–25 islands, primarily related to translation regulation, transposition, and transposase activity. Analysis of virulence factors using the virulence factors database (VFDB) highlighted 1252 virulence genes within these islands, with a significant portion (36.5%) linked to effector transport systems, predominantly the type III secretion system (66.7%). Each strain averaged 60 type III effector proteins, with RipBK and RipAZ2 unique to highly pathogenic strains. This study provides a comprehensive understanding of pan-genome of R. pseudosolanacearum causing tobacco bacterial wilt in China, providing valuable insights into virulence variation and environmental adaptation of the pathogen.SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12866-025-04485-4.PMID:41291432 | PMC:PMC12645687 | DOI:10.1186/s12866-025-04485-4