Jacobs Janette L, Fasi Anthony C, Ramette Alban, Smith James J, Hammerschmidt Raymond, Sundin George W
Department of Plant Pathology, Michigan State University, 62 PBL, East Lansing, MI 48824, USA.
Appl Environ Microbiol. 2008 May;74(10):3121-9. doi: 10.1128/AEM.01941-07. Epub 2008 Mar 14.
Burkholderia cepacia complex strains are genetically related but phenotypically diverse organisms that are important opportunistic pathogens in patients with cystic fibrosis (CF,) as well as pathogens of onion and banana, colonizers of the rhizospheres of many plant species, and common inhabitants of bulk soil. Genotypic identification and pathogenicity characterization were performed on B. cepacia complex isolates from the rhizosphere of onion and organic soils in Michigan. A total of 3,798 putative B. cepacia complex isolates were recovered on Pseudomonas cepacia azelaic acid tryptamine and trypan blue tetracycline semiselective media during the 2004 growing season from six commercial onion fields located in two counties in Michigan. Putative B. cepacia complex isolates were identified by hybridization to a 16S rRNA gene probe, followed by duplex PCR using primers targeted to the 16S rRNA gene and recA sequences and restriction fragment length polymorphism analysis of the recA sequence. A total of 1,290 isolates, 980 rhizosphere and 310 soil isolates, were assigned to the species B. cepacia (160), B. cenocepacia (480), B. ambifaria (623), and B. pyrrocinia (27). The majority of isolates identified as B. cepacia (85%), B. cenocepacia (90%), and B. ambifaria (76%) were pathogenic in a detached onion bulb scale assay and caused symptoms of water soaking, maceration, and/or necrosis. A phylogenetic analysis of recA sequences from representative B. cepacia complex type and panel strains, along with isolates collected in this study, revealed that the B. cenocepacia isolates associated with onion grouped within the III-B lineage and that some strains were closely related to strain AU1054, which was isolated from a CF patient. This study revealed that multiple B. cepacia complex species colonize the onion rhizosphere and have the potential to cause sour skin rot disease of onion. In addition, the onion rhizosphere is a natural habitat and a potential environmental source of B. cenocepacia.
洋葱伯克霍尔德菌复合体菌株在基因上相关，但在表型上具有多样性，它们是囊性纤维化（CF）患者重要的机会致病菌，也是洋葱和香蕉的病原菌、许多植物物种根际的定殖菌以及大量土壤中的常见栖居菌。对从密歇根州洋葱根际和有机土壤中分离出的洋葱伯克霍尔德菌复合体菌株进行了基因型鉴定和致病性特征分析。在2004年生长季节，从密歇根州两个县的六个商业洋葱田的假单胞菌洋葱伯克霍尔德菌壬二酸色胺和台盼蓝四环素半选择性培养基上共回收了3798株假定的洋葱伯克霍尔德菌复合体菌株。通过与16S rRNA基因探针杂交来鉴定假定的洋葱伯克霍尔德菌复合体菌株，随后使用靶向16S rRNA基因和recA序列的引物进行双重PCR，并对recA序列进行限制性片段长度多态性分析。总共1290株分离株，980株根际分离株和310株土壤分离株，被归类为洋葱伯克霍尔德菌（160株）、洋葱伯克霍尔德菌（480株）、类洋葱伯克霍尔德菌（623株）和吡咯伯克霍尔德菌（27株）。在离体洋葱鳞茎鳞片试验中，大多数被鉴定为洋葱伯克霍尔德菌（85%）、洋葱伯克霍尔德菌（90%）和类洋葱伯克霍尔德菌（76%）的分离株具有致病性，并引起水渍、浸软和/或坏死症状。对代表性的洋葱伯克霍尔德菌复合体类型菌株和参比菌株以及本研究中收集的分离株的recA序列进行系统发育分析，结果表明与洋葱相关的洋葱伯克霍尔德菌分离株聚集在III - B谱系内，并且一些菌株与从CF患者分离出的AU1054菌株密切相关。这项研究表明，多种洋葱伯克霍尔德菌复合体物种定殖在洋葱根际，并有可能导致洋葱酸腐病。此外，洋葱根际是类洋葱伯克霍尔德菌的自然栖息地和潜在的环境来源。
