Liu J, Berry R E, Blouin M S
Department of Entomology, Oregon State University, Corvallis, Oregon 97331-2914, USA.
J Invertebr Pathol. 2001 Feb;77(2):87-91. doi: 10.1006/jipa.2001.5007.
Two species of entomopathogenic nematodes, Heterorhabditis marelatus and Steinernema oregonense, were described recently from the west coast of North America. It is not known whether the bacterial symbionts of these nematodes are also unique. Here we compared partial 16S rRNA sequences from the symbiotic bacteria of these two nematodes with sequence from previously described Photorhabdus and Xenorhabdus species. The 16S sequence from the new Xenorhabdus isolate appears very similar to, although not identical to, that of X. bovienii, the common symbiont of S. feltiae. The new Photorhabdus isolate appears to be very distinct from other known Photorhabdus species, although its closest affinities are with the P. temperata group. We also verified a monoxenic association between each isolate and its nematode by amplifying and sequencing bacterial 16S sequence from crushed adult and juvenile nematodes and from bacterial cultures isolated from infected hosts.
最近在北美洲西海岸发现了两种昆虫病原线虫，即马里兰异小杆线虫（Heterorhabditis marelatus）和俄勒冈斯氏线虫（Steinernema oregonense）。目前尚不清楚这些线虫的细菌共生体是否也具有独特性。在此，我们将这两种线虫共生细菌的部分16S rRNA序列与先前描述的发光杆菌属（Photorhabdus）和致病杆菌属（Xenorhabdus）物种的序列进行了比较。新分离出的致病杆菌属菌株的16S序列与斯氏线虫（Steinernema feltiae）常见共生体——博维致病杆菌（Xenorhabdus bovienii）的序列非常相似，但并不完全相同。新分离出的发光杆菌属菌株似乎与其他已知的发光杆菌属物种有很大区别，尽管它与温和发光杆菌（Photorhabdus temperata）组关系最为密切。我们还通过对碾碎的成年和幼年线虫以及从受感染宿主分离出的细菌培养物中的细菌16S序列进行扩增和测序，验证了每个分离菌株与其线虫之间的单菌共栖关系。
