桑细菌性枯萎病病原菌的分离鉴定与全基因组序列分析

Isolation,identification and whole-genome sequence analysis of the pathogen causing mulberry bacterial wilt disease

为明确华南蚕区桑树细菌性枯萎病主要病原菌的种类,本研究从广西、广东等地桑园采集了多份桑树细菌性枯萎病病样,采用分离培养、形态学鉴定和分子生物学鉴定的方法,对病原菌进行了分离鉴定,并通过药敏试验分析病原菌的耐药性。结果表明,结合柯赫氏法则,将分离到的桑枯萎病病原菌鉴定为产酸克雷伯氏菌Klebsiella oxytoca,编号AKKL-001(菌种保藏号GDMCC No.1.1602)。该病原菌属革兰氏阴性菌,基因组全长6149586 bp,含有5792个基因,GC含量55.80%;药敏试验结果表明,病原菌对氨苄西林、头孢唑啉、头孢呋辛、头孢噻吩、链霉素、麦迪霉素等抗生素具有耐受性。本研究报道了桑细菌性枯萎病病样上分离的产酸克雷伯氏菌,为桑细菌性枯萎病病原菌的研究提供理论依据,全基因组测序的结果为桑细菌性枯萎病的相关致病机制研究奠定了基础。

In order to identify the main pathogens of mulberry bacterial wilt in the silkworm-rearing area of South China,multiple mulberry samples with mulberry bacterial wilt were collected from mulberry fields in gardens in Guangxi and Guangdong.The pathogen was isolated and identified by culture separation,morphological and molecular identification.Meanwhile,drug sensitivity test was conducted to analyze the drug resistance of pathogenic bacteria.The results showed that,combined with Koch’s postulates,a strain of Klebsiella oxytoca,the pathogen of mulberry wilt disease,was isolated,designated as AKKL-001(GDMCC strain deposit no.1.1602).The pathogen was a gram-negative bacterium with a full-length genome sequence of 6149586 bp,including 5792 genes,with a GC content of 55.80%.The results of drug sensitivity test showed that the pathogen was resistant to antibiotics such as ampicillin,cefazolin,cefuroxime,cephalothin,streptomycin and midecamycin.This study reported Klebsiella oxytoca isolated from samples of mulberry bacterial wilt disease,which provided a theoretical basis for the research on the pathogen of mulberry bacterial wilt,and the results of whole-genome sequencing provided the basis for the identification of the related pathogenic mechanism of mulberry bacterial wilt.