湘西地区猕猴桃溃疡病病原菌分离及其全基因组分析

通过了解湘西地区猕猴桃溃疡病致病菌分类地位和基因类型，初步探讨其致病的分子机理。采用纯培养法分离猕猴桃溃疡病菌；基于16S～23S rRNA基因内转录间隔序列进行病原菌的系统发育分析；通过基因组测序和生物信息学分析解析其致病的分子机理。从“米良1号”和“红阳”猕猴桃感病枝条中分离获得5株溃疡病菌，编号为L211、L212、L321、L322、L323;通过形态特征和16S～23S rRNA基因内转录间隔序列分析，鉴定5株细菌均为丁香假单胞菌猕猴桃致病变种(Pseudomonas syringae pv.actinidae,Psa)。以菌株L211为代表进行体外猕猴桃枝条接种实验表明能引起典型溃疡病症状。通过菌株L211的全基因组测序和生物信息学分析，获得5 741条基因数目，长5 412 072 bp;基因功能注释发现菌株L211携带121种毒力因子、71个植物互作因子和77个耐药基因；同时，基因组单核苷酸多态性分析发现病原菌L211为基因Ⅲ型Psa。引起湘西地区猕猴桃溃疡病的病原菌是丁香假单胞菌猕猴桃致病变种基因Ⅲ型，与国内外报道的引起猕猴桃溃疡病大流行的致病菌一致。猕猴桃溃疡病发病...

Isolation of Kiwifruit Canker Pathogen in Western Hunan and Whole Genome Sequencing Analysis of Its Pathogenic Mechanism

Taxonomic status and genotypes of kiwifruit canker bacteria in western Hunan was clarified and preliminarily explored the molecular mechanism of the pathogenesis. Bacteria pathogens of kiwifruit were isolated by culture-dependent methods, and identified based on sequence analysis of the internal transcribed spacer of 16S-23S rRNA gene. Genome sequencing and bio-information analysis were used to explore the molecular mechanism of the pathogenic bacterium. The results showed that five strains of bacterial pathogens, named after strain L211, L212, L321, L322, L323, were isolated from the infected branches of the kiwifruit " Miliang No.1" and "Hong Yang" in western Hunan, and these were identified as Pseudomonas syringae pv. actinidae (Psa). In vitro branching inoculation experiments using the L211 strain as a representative showed that it could cause typical kiwifruit canker disease. Following whole genome sequencing of strain L211 and bioinformation analysis, 5 741 genes with a total length of 5 412 072 bp were obtained, L211 strain was found to harbor 121 virulence factors, 71 plant-interactions factors and 77 drug-resistance genes. Single nucleotide polymorphism analysis indicated that the L211 strain belonged to the Psa biovar Ⅲ. To conclude, Psa biovar Ⅲ is the leading cause of kiwifruit canker disease in western Hunan, which is the same pathogenic bacterium bringing about global pandemic kiwifruit canker as reported home and abroad. The pathogenesis of kiwifruit canker disease may be the result of the synergistic action of multiple virulence and reciprocal genes of the pathogen.