Duan Y P, Castro H F, Hewlett T E, White J H, Ogram A V
Soil and Water Science Department, University of Florida, Gainesville, FL 32611-0290, USA.
Entomos LLC, Gainesville, FL, USA.
Int J Syst Evol Microbiol. 2003 Jan;53(Pt 1):105-112. doi: 10.1099/ijs.0.02303-0.
Various bacterial species in the genus Pasteuria have great potential as biocontrol agents against plant-parasitic nematodes, although study of this important genus is hampered by the current inability to cultivate Pasteuria species outside their host. To aid in the study of this genus, an extensive 16S rRNA gene sequence phylogeny was constructed and this information was used to develop cultivation-independent methods for detection of Pasteuria in soils and nematodes. Thirty new clones of Pasteuria 16S rRNA genes were obtained directly from nematodes and soil samples. These were sequenced and used to construct an extensive phylogeny of this genus. These sequences were divided into two deeply branching clades within the low-G + C, Gram-positive division; some sequences appear to represent novel species within the genus Pasteuria. In addition, a surprising degree of 16S rRNA gene sequence diversity was observed within what had previously been designated a single strain of Pasteuria penetrans (P-20). PCR primers specific to Pasteuria 16S rRNA for detection of Pasteuria in soils were also designed and evaluated. Detection limits for soil DNA were 100-10,000 Pasteuria endospores (g soil)(-1).
巴氏杆菌属中的各种细菌物种作为植物寄生线虫的生物防治剂具有巨大潜力，尽管目前无法在宿主之外培养巴氏杆菌属物种，这阻碍了对这一重要属的研究。为了帮助对该属进行研究，构建了一个广泛的16S rRNA基因序列系统发育树，并利用这些信息开发了不依赖培养的方法来检测土壤和线虫中的巴氏杆菌。直接从线虫和土壤样本中获得了30个巴氏杆菌16S rRNA基因的新克隆。对这些克隆进行测序并用于构建该属的广泛系统发育树。这些序列在低G + C含量的革兰氏阳性菌分类中分为两个深度分支的进化枝；一些序列似乎代表了巴氏杆菌属内的新物种。此外，在之前被指定为单株穿刺巴氏杆菌（P-20）的菌株中观察到了惊人程度的16S rRNA基因序列多样性。还设计并评估了用于检测土壤中巴氏杆菌的特异性针对巴氏杆菌16S rRNA的PCR引物。土壤DNA的检测限为每克土壤100 - 10000个巴氏杆菌内生孢子。
