Li Xinshen, Huang Xiaomei, Chen Gongyou, Zou Lifang, Wei Lingen, Hua Juling
Institute of Plant Protection, Jiangxi Academy of Agricultural Sciences, Nanchang, China.
Agricultural Service Training and Development Department, Jiangxi Biotech Vocational College, Nanchang, China.
Genes Genomics. 2018 Jun;40(6):657-668. doi: 10.1007/s13258-018-0667-3. Epub 2018 Feb 8.
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.
青枯雷尔氏菌是一种与芝麻青枯病相关的土传植物病原体。青枯雷尔氏菌是从热带到温带地区导致猝倒病的主要病原体。由于青枯病降低了芝麻产业的产量，我们使用PacBio和Illumina HiSeq 2500系统对SEPPX05基因组进行了测序，结果显示青枯雷尔氏菌菌株SEPPX05携带一个二分体基因组，由一条3,930,849 bp的染色体和一个2,066,085 bp的大质粒组成，其G+C含量为66.84%，含有5,427个编码序列。基于全基因组的系统发育分析表明，菌株SEPPX05与两个I型菌株（EP1和GMI1000）聚为一类。泛基因组分析表明，青枯雷尔氏菌是一个具有高度生物多样性的复杂物种，并且在进化过程中能够定殖于各种环境。尽管存在缺失、插入和倒位，但与菌株GMI1000相比，菌株SEPPX05的大多数基因具有相对较高的共线性水平。我们在SEPPX05基因组中鉴定出104个与毒力相关因子有关的基因以及8个GMI1000中缺失的编码III型效应蛋白（T3E）的基因。将SEPPX05与其他物种进行比较时，我们发现了对调节宿主细菌相互作用至关重要的高度保守的分泌系统。这些数据可能为理解青枯雷尔氏菌的潜在致病机制提供重要线索，并有助于控制芝麻青枯病。
