Population biology analysis of Pythium cryptoirregulare in rhododendron nursery soils in Oregon

Abstract

Pythium cryptoirregulare (Garzon, Yanez and Moorman) is a recently described plant pathogenic species. P. cryptoirregulare was originally believed to belong to the species of Pythium irregulare, however, ITS and cox I-II sequencing, and colony morphology determined that this was actually a new species, with different characteristics from those of P. irregulare sensu stricto. P. cryptoirregulare causes major disease problems for nursery growers in the Pacific Northwest each year. Millions of acres suffer from root rots and damping off. Through the use of population biology studies, we can assess the movement of this pathogen as well as other epidemiological information on the species.

This study takes a deeper look into the population structure of this species. Using isolates from rhododendron nurseries in Oregon, we assess the genetic differentiation among populations of this species in order to determine patterns and gain information on genetic relatedness within and among populations of the species. Using population genetic analyses, we were able to visualize epidemiological patterns within four rhododendron nursery populations of P. cryptoirregulare. With this information, we will be able to provide better management recommendations to nursery growers who deal with the major damages that P. cryptoirregulare causes through root rots and damping off.