Ffrench-Constant R H, Waterfield N, Burland V, Perna N T, Daborn P J, Bowen D, Blattner F R
Department of Biology and Biochemistry, University of Bath, United Kingdom.
Appl Environ Microbiol. 2000 Aug;66(8):3310-29. doi: 10.1128/AEM.66.8.3310-3329.2000.
Photorhabdus luminescens is a pathogenic bacterium that lives in the guts of insect-pathogenic nematodes. After invasion of an insect host by a nematode, bacteria are released from the nematode gut and help kill the insect, in which both the bacteria and the nematodes subsequently replicate. However, the bacterial virulence factors associated with this "symbiosis of pathogens" remain largely obscure. In order to identify genes encoding potential virulence factors, we performed approximately 2,000 random sequencing reads from a P. luminescens W14 genomic library. We then compared the sequences obtained to sequences in existing gene databases and to the Escherichia coli K-12 genome sequence. Here we describe the different classes of potential virulence factors found. These factors include genes that putatively encode Tc insecticidal toxin complexes, Rtx-like toxins, proteases and lipases, colicin and pyocins, and various antibiotics. They also include a diverse array of secretion (e.g., type III), iron uptake, and lipopolysaccharide production systems. We speculate on the potential functions of each of these gene classes in insect infection and also examine the extent to which the invertebrate pathogen P. luminescens shares potential antivertebrate virulence factors. The implications for understanding both the biology of this insect pathogen and links between the evolution of vertebrate virulence factors and the evolution of invertebrate virulence factors are discussed.
发光光杆状菌是一种致病细菌，存在于昆虫致病线虫的肠道中。线虫侵入昆虫宿主后，细菌从线虫肠道释放出来，帮助杀死昆虫，细菌和线虫随后在昆虫体内繁殖。然而，与这种“病原体共生”相关的细菌毒力因子在很大程度上仍不清楚。为了鉴定编码潜在毒力因子的基因，我们从发光光杆状菌W14基因组文库中进行了约2000次随机测序读数。然后，我们将获得的序列与现有基因数据库中的序列以及大肠杆菌K-12基因组序列进行比较。在此，我们描述了发现的不同类别的潜在毒力因子。这些因子包括推定编码Tc杀虫毒素复合物、Rtx样毒素、蛋白酶和脂肪酶、大肠杆菌素和绿脓菌素以及各种抗生素的基因。它们还包括一系列不同的分泌系统（如III型）、铁摄取系统和脂多糖产生系统。我们推测了这些基因类别在昆虫感染中的潜在功能，并研究了无脊椎动物病原体发光光杆状菌共享潜在抗脊椎动物毒力因子的程度。讨论了对于理解这种昆虫病原体的生物学以及脊椎动物毒力因子的进化与无脊椎动物毒力因子的进化之间联系的意义。
