38th Annual Meeting of the Society for Invertebrate Pathology

Zoophthora radicans and Pandora blunckii co-occur in Plutella xylostella populations contributing to population regulation. Interactions between the species have not been studied and are important to our understanding of how they co-exist in agroecosystems and how they can best be exploited in microbial control. Intraspecific variation in ribosomal DNA amongst 39 isolates of Z. radicans and 21 isolates of P. blunckii was studied using amplification of the ITS region and RFLP analysis. Variability was greater amongst Z. radicans isolates than P. blunckii isolates. Partial sequencing of the ITS region of selected isolates from both species was used to develop species-specific diagnostic primers. Using these primers SYBR Green Real Time PCR assays were developed for Z. radicans allowing us to quantify the amount of Z. radicans DNA present within infected hosts when they had been inoculated with Z. radicans alone or co-inoculated with P. blunckii. The outcomes of these competitive interactions between different isolates of each species were strongly related to isolate virulence and dose. The implications of these studies are discussed in relation to the ecology of these species and their potential in microbial control.