Complete genome sequence of the sesame pathogen Ralstonia solanacearum strain SEPPX 05
Ralstonia solanacearum is a soil-borne phytopathogen associated with bacterial wilt disease of sesame. R. solanacearum is the predominant agent causing damping-off from tropical to temperate regions. Because bacterial wilt has decreased the sesame industry yield, we sequenced the SEPPX05 genome using PacBio and Illumina HiSeq 2500 systems and revealed that R. solanacearum strain SEPPX05 carries a bipartite genome consisting of a 3,930,849 bp chromosome and a 2,066,085 bp megaplasmid with 66.84% G+C content that harbors 5,427 coding sequences. Based on the whole genome, phylogenetic analysis showed that strain SEPPX05 is grouped with two phylotype I strains (EP1 and GMI1000). Pan-genomic analysis shows that R. solanacearum is a complex species with high biological diversity and was able to colonize various environments during evolution. Despite deletions, insertions, and inversions, most genes of strain SEPPX05 have relatively high levels of synteny compared with strain GMI1000. We identified 104 genes involved in virulence-related factors in the SEPPX05 genome and eight absent genes encoding T3Es of GMI1000. Comparing SEPPX05 with other species, we found highly conserved secretion systems central to modulating interactions of host bacteria. These data may provide important clues for understanding underlying pathogenic mechanisms of R. solanacearum and help in the control of sesame bacterial wilt.
KeywordsRalstonia solanacearum Genome sequencing Genome comparison Virulence
We thank Prof. Xiangmin Li (Institute of Plant Protect, Jiangxi Academy of Agricultural Sciences, China) for reviewing the manuscript and giving valuable suggestions and Zoe Rouy for genomes integration of strain SEPPX05 into the MaGe platform.
XL performed annotation of the genome. XL and JL designed the experiments and wrote the paper. XH, GC, LZ and LW contributed to data analysis. XL and XH isolated the R. solanacearum strain SEPPX05. XL and JL revised the manuscript. All of the authors read and approved the final manuscript.
This work were supported by National Natural Science Foundation of China (NSFC, Grant Number 31,360,428), Key Technology Research and Development Program Jiangxi Proveince (Grant Number: 20121BBF60015), and Innovation Fund for the Doctoral Program of Jiangxi Academy of Agricultural Sciences (Grant Number: 20142C13S006). National Industry Technical System of Secondary Centre of Oil Crops (Grant Number: CARS-14).
Compliance with ethical standards
Xinshen Li declares that he has no conflict of interest. Xiaomei Huang declares that she has no conflict of interest. Gongyou Chen declares that he has no conflict of interest. Lifang Zou declares that she has no conflict of interest. Lingen Wei declares that he has no conflict of interest. Juling Hua declares that she has no conflict of interest.
Research involving human and animal rights
This article does not contain any studies with human or animals subjects performed by any of the authors.
All the experiments were performed according to the experiment security regulations of Jiangxi Academy of Agricultural Sciences (JAAS), and approved by the biosafety committee in JAAS.
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