唐菖蒲伯克霍尔德菌椰毒致病变种食物中毒分离株的遗传特性研究

目的 对1株引起聚集性米酵菌酸中毒的生吊面浆食品样品分离株唐菖蒲伯克霍尔德菌椰毒致病变种(Burkholderia gladioli pv. cocovenenans)DBJ进行全基因组测序并分析,解析菌株产毒及致病的基因特征。方法 提取唐菖蒲伯克霍尔德菌椰毒致病变种DBJ基因组DNA,对菌株进行测序获得全基因组完成图,利用生物信息学分析手段对序列进行挖掘分析。结果 菌株DBJ基因组由两个染色体(G1和G2)和一个质粒(P)组成,其中两个染色体大小均为4 Mb左右,质粒大小约为300 kb。两个染色体的GC含量也相仿,约为68.0%,质粒则稍低为63.0%。进一步分析发现,G2染色体上存在产米酵菌酸的bon基因簇。遗传进化分析后发现,菌株DBJ在亲缘关系上与加拿大玉米分离株UCD-UG_CHAPALOTE最为接近,两株菌处在同一进化分支。且255株菌种中有31株携带bon基因簇的菌株,较不携带该基因的唐菖蒲伯克霍尔德菌有明显遗传进化倾向。结论 唐菖蒲伯克霍尔德菌椰毒致病变种DBJ分离株基因组中携带产米酵菌酸的bon基因簇,是引起食物中毒的主要原因。

Genetic characteristics of Burkholderia gladiolus pv. cocovenenans isolated from poisonous food

Objective Whole genome sequencing and analysis was conducted on a Burkholderia gladiolus pv. cocovenenans strain, isolated from raw corn flour sample which caused family agglutinative bongkrekic acid poisoning. The genetic characteristics of its virulence and pathogenicity were analyzed as well. Methods Genomic DNA was extracted from DBJ isolate, the whole genome sequencing was carried out. Bioinformatics method were used to mine and analyze the data obtained from sequencing. Results Two independent chromosomes (G1 and G2) and one plasmid (P) were found in DBJ isolate. The lengths of the chromosomes and plasmid were about 4 Mb and 300 kb respectively. The GC content of the two chromosomes was both around 68.0%, and that of the plasmid was slightly lower at 63.0%. The bon gene cluster was found on chromosome G2. The phylogenetic analysis showed that DBJ isolate and UCD-UG_CHAPALOTE stain which was isolated from corn sample in Canada were in the same clade. Among 255 strains, 31 carrying bon gene cluster and they had obvious genetic evolutionary tendency. Conclusion The bon gene cluster was located on the chromosome of Burkholderia gladiolus pv. cocovenenans DBJ, and it was the main pathogenic gene causing food poisoning in human.