Comparative Analysis of Quorum Sensing-Dependent Transcriptomic Responses in Phytopathogenic <i>Burkholderia</i> spp.

Rice is a crucial global crop of nutritional and economic importance. Burkholderia glumae, Burkholderia gladioli, and Burkholderia plantarii are the major phytopathogens that cause diseases in rice within the genus Burkholderia. These phytopathogenic Burkholderia spp. have an acylated homoserine lactone (AHL)-based quorum sensing (QS) system that regulates gene expression depending on the cell density. Differentially expressed genes (DEGs) between B. plantarii KACC 18965 wildtype and plaI deletion mutant were analyzed to understand the plaI-mediated QS system in B. plantarii, and transcriptome profiles were compared across three phytopathogenic Burkholderia spp. (B. glumae, B. gladioli, and B. plantarii) to investigate the impact of QS on their pathogenicity. Clusters of Orthologous Groups category and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses confirmed that diverse metabolic processes were regulated by QS in the three phytopathogenic Burkholderia spp. Additionally, characteristic differences in the regulation of gene expression across the three phytopathogenic Burkholderia spp. were observed in DEGs belonging to the bacterial secretion system (ko03070) pathway, using KEGG pathway analysis. The characterization and comparison of transcriptome profiles between phytopathogenic Burkholderia spp. in this study offers deeper insights into AHL-mediated QS systems in phytopathogenic Burkholderia spp. These results provide a foundation for future studies on the QS-based biology and pathogenicity of phytopathogenic Burkholderia spp.