# First genomic analysis of a strain of Ralstonia pseudosolanacearum isolated from Mayotte island

## TL;DR

This paper presents the first complete genome of a Ralstonia pseudosolanacearum strain from Mayotte, offering insights into its potential role in agricultural disease spread.

## Contribution

The study provides the first genomic analysis of a Ralstonia pseudosolanacearum isolate from Mayotte, revealing unique plasmid features.

## Key findings

- The RUN2161 genome includes a megaplasmid with both Type IV and Type II secretion system genes.
- The isolate's genome is assembled into one chromosome, one megaplasmid, and one plasmid.
- Accessory plasmids are rare in the Ralstonia solanacearum species complex.

## Abstract

The Ralstonia solanacearum species complex (RSSC) encompasses phytopathogenic bacteria responsible for bacterial wilt, a devastating disease affecting a wide range of agriculturally important crops. In the South-West Indian Ocean, lineage I-18 of R. pseudosolanacearum has emerged as a particularly destructive pathogen, posing a serious threat to regional food security. In this context, we report the complete genome sequence of isolate RUN2161, collected in Mayotte. This first genome from this island provides a valuable resource for unraveling the evolutionary and epidemiological mechanisms driving the emergence and spread of highly epidemic strains in agriculture..

The genome of strain RUN2161 from Mayotte was sequenced using Illumina short reads and Nanopore long reads. A hybrid assembly was performed resulting in a complete genome of 5,989,529 bp with a G + C content of 66.7%. Functional annotation identified 5,268 CDS, 12 rRNAs, 61 tRNA genes, and 4 ncRNAs, assembled into one chromosome, one megaplasmid and one plasmid. Accessory plasmids are uncommon in RSSC. The RUN2161 plasmid contains Type IV secretion system genes, commonly found on conjugative plasmids, but less commonly, it also carries Type II secretion system genes involved in secretion of toxins and degradative enzymes, which could contribute to epidemiological success.