Genome analysis and hyphal movement characterization of the hitchhiker endohyphal Enterobacter sp. from Rhizoctonia solani

• Published in: Applied and environmental microbiology Vol. 90; no. 3; p. e0224523
• Main Authors: Zhang, Peiqi, Huguet-Tapia, Jose, Peng, Zhao, Liu, Sanzhen, Obasa, Ken, Block, Anna K, White, Frank F
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 20.03.2024
• Subjects: Acetic acid; Bacteria; Biosynthesis; Cyanates; Ecology; Enterobacter; Enterobacter - genetics; Enterobacter - metabolism; Flagella; Fungi; Genes; Genomes; Genomic islands; Heavy metals; Hyphae; Hyphae - metabolism; Indoleacetic acid; Metals; Pathogenicity; Pathogens; Phenylacetates - metabolism; Phenylacetic acid; Phylogeny; Plant Microbiology; Plasmids; Rhizoctonia - genetics; Rhizoctonia solani; Rhizosphere; bacterial hitchhiker; Enterobacter; prophage; type VI secretion system; endohyphal bacteria; Rhizoctonia solani; brown patch disease; phenylacetic acid; comparative genomics; fungal-bacterial interaction
• ISSN: 0099-2240; 1098-5336; 1098-5336
• DOI: 10.1128/aem.02245-23

Bacterial-fungal interactions are pervasive in the rhizosphere. While an increasing number of endohyphal bacteria have been identified, little is known about their ecology and impact on the associated fungal hosts and the surrounding environment. In this study, we characterized the genome of an sp. Crenshaw (En-Cren), which was isolated from the generalist fungal pathogen and examined the genetic potential of the bacterium with regard to the phenotypic traits associated with the fungus. Overall, the En-Cren genome size was typical for members of the genus and was capable of free-living growth. The genome was 4.6 MB in size, and no plasmids were detected. Several prophage regions and genomic islands were identified that harbor unique genes in comparison with phylogenetically closely related spp. Type VI secretion system and cyanate assimilation genes were identified from the bacterium, while some common heavy metal resistance genes were absent. En-Cren contains the key genes for indole-3-acetic acid (IAA) and phenylacetic acid (PAA) biosynthesis, and produces IAA and PAA , which may impact the ecology or pathogenicity of the fungal pathogen . En-Cren was observed to move along hyphae of and on other basidiomycetes and ascomycetes in culture. The bacterial flagellum is essential for hyphal movement, while other pathways and genes may also be involved.IMPORTANCEThe genome characterization and comparative genomics analysis of sp. Crenshaw provided the foundation and resources for a better understanding of the ecology and evolution of this endohyphal bacteria in the rhizosphere. The ability to produce indole-3-acetic acid and phenylacetic acid may provide new angles to study the impact of phytohormones during the plant-pathogen interactions. The hitchhiking behavior of the bacterium on a diverse group of fungi, while inhibiting the growth of some others, revealed new areas of bacterial-fungal signaling and interaction, which have yet to be explored.