Publications - Faculty - Recently Submitted Faculty Publications 2010
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Duncan - Parasitology
Real-time PCR as an effective technique to assess the impact of phoresy by Paenibacillus sp. bacteria on Steinernema diaprepesi nematodesin nature
R. CAMPOS-HERRERA1, 2*, F. E. EL-BORAI1, 3, and L. W. DUNCAN1
Abstract.Quantitative real-time PCR (qPCR) is a powerful tool to study species of cryptic organisms in complex food webs. This technique was recently developed to detect and quantify several species of entomopathogenic nematodes (EPNs), which are widely used for biological control of insects, and some natural enemies of EPNs such as nematophagous fungi and the phoretic bacteria Paenibacillus sp. and P. nematophilus. A drawback to the use of primers and TaqMan probes designed for Paenibacillus sp. is that the qPCR also amplified P. thiaminolyticus and P. popilliae, two closely-related species that are not phoretically associated with EPNs. Here we report that the detection of Paenibacillus sp. DNA in nematode samples was two orders of magnitude greater (P < 0.001) when the bacterium was added to soil as free spores together with its EPN species-specific host Steinernema diaprepesi, than when it was added concomitantly with other EPNs or with species of bacterial feeding nematodes. Just 6% of samples detected trace amounts of P. thiaminolyticus and P. popilliae exposed to the same experimental conditions. Thus, although the molecular assay detects Paenibacillus spp. spores in non-phoretic associations, the levels are essentially background compared to detection of Paenibacillus sp. in association with its nematode host.
