洋葱伯克氏菌基因型的鉴定及其在苜蓿模型上的毒力分析

Identification of the Burkholderia cepacia complex genomovars and their virulence in an alfalfa infection model

摘要:

摘要：【目的】证实来自我国农业和医院环境中部分洋葱伯克氏菌的基因型并通过苜蓿植物模型探测不同基因型对人体的可能毒力。【方法】采用洋葱伯克氏菌基因型的PCR特异性扩增技术对来源于根围、土壤和医院中的57株洋葱伯克氏菌进行了基因型的鉴定，并利用苜蓿植物模型对这些基因型菌株进行了毒力探测。【结果】获得4种不同的基因型，包括基因型Ⅰ、ⅢA、ⅢB、Ⅴ和Ⅸ。来源于医院的基因型Ⅰ和ⅢA菌株以及根围的基因型ⅢB菌株均对苜蓿幼苗有较强的毒力，其对苜蓿幼苗的平均发病率分别达到69%、68%和55%，与农田环境中基因型Ⅴ和Ⅸ对苜蓿幼苗的发病率相比,表现出显著的差异性。【结论】农田环境中洋葱伯克菌的基因型在苜蓿模型上的毒力差异大，根围的基因型ⅢB菌株对苜蓿幼苗具有强毒力，其毒力程度接近于医院致病基因型ⅢA菌。

关键词:关键词：洋葱伯克氏菌;基因型;苜蓿;毒力

Abstract:

Abstract: [Objective] To confirm Burkholderia cepacia complex (Bcc) genomovars from agricultural niches and clinical samples, and to evaluate their possible virulence to human body on alfalfa infection model in China. [Methods] A total of 57 Bcc strains were isolated and collected from the rhizosphere, soil and clinical samples in China. The genomovars composition of the Bcc strains was analyzed by species-specific PCR tests, and the virulence of the Bcc strains was tested on alfalfa seedlings. [Results] Four genomovars of the ten genomovars were detected among the Bcc strains, including B. cepacia (genomovarⅠ), B. cenocepacia (genomovarⅢ), B. vietnamiensis (genomovarⅤ) and B. pyrrocinia (genomovar Ⅸ). Bcc genomovarsⅠandⅢA from clinic, and genomovarⅢB from rhizosphere were the most virulent in the alfalfa infection model, and caused symptoms in 69%, 68% and 55% of seedlings, respectively. There were significant variances in the mean percentage of seedlings with symptoms for genomovarsⅠ,ⅢA andⅢB compared to those for genomovarⅤandⅨ. [Conclusion] There was difference in the ability to cause disease in alfalfa for different genomovar strains from agricultural inches. The strains of Bcc genomovarⅢB from rhizosphere were more virulent similar to those of Bcc geno-movarⅢA from clinic.

Key words:Keywords: Burkholderia cepacia complex; genomovar; alfalfa; virulence