1 research outputs found
Entomopathogenic nematodes, phorectic Paenibacillus spp., and the use of real time quantitative PCR to explore soil food webs in Florida citrus groves
10 páginas, ilustraciones y tablas estadísticas.Quantitative real-time PCR (qPCR) is a powerful tool to detect and quantify species of cryptic organisms
such as bacteria, fungi and nematodes from soil samples. As such, qPCR offers new opportunities to study
the ecology of soil habitats by providing a single method to characterize communities of diverse organisms
from a sample of DNA. Here we describe molecular tools to detect and quantify two bacteria (Paenibacillus
nematophilus and Paenibacillus sp.) phoretically associated with entomopathogenic nematodes
(EPNs) in the families Heterorhabditidae and Steinernematodae. We also extend the repertoire of species
specific primers and TaqMan probes for EPNs to include Heterorhabditis bacteriophora, Steinernema
carpocapsae, Steinernema feltiae and Steinernema scapterisci, all widely distributed species used commercially
for biological control. Primers and probes were designed from the ITS rDNA region for the EPNs and
the 16S rDNA region for the bacteria. Standard curves were established using DNA from pure cultures of
EPNs and plasmid DNA from the bacteria. The use of TaqMan probes in qPCR resolved the non-specificity
of EPN and some bacterial primer amplifications whereas those for Paenibacillus sp. also amplified Paenibacillus
thiaminolyticus and Paenibacillus popilliae, two species that are not phoretically associated with
nematodes. The primer-probe sets for EPNs were able to accurately detect three infective juvenile EPNs
added to nematodes recovered from soil samples. The molecular set for Paenibacillus sp. detected the bacterium
attached to Steinernema diaprepesi suspended in water or added to nematodes recovered from soil
samples but its detection decreased markedly in the soil samples, even when a nested PCR protocol was
employed. Using qPCR we detected S. scapterisci at low levels in a citrus grove, which suggested natural
long-distance spread of this exotic species, which is applied to pastures and golf courses to manage mole
crickets (Scapteriscus spp.). Paenibacillus sp. (but not P. nematophilus) was detected in low quantities in
the same survey but was unrelated to the spatial pattern of S. diaprepesi. The results of this research validate
several new tools for studying the ecology of EPNs and their phoretic bacteria.(CGL-2009-14686-C01-00 BOS y (FP7-PEOPLE-2009-IOF-252980Peer reviewe