Alternative Control Mechanisms to Prevent Infection by the Plant Pathogens Pythium Aphanidrmatum and Pythium Ultimum


Zac Zabriskie

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USU Student Showcase

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Faculty Mentor

Annie Anderson


Members of the oomycete genus Pythium are common plant pathogens. Many isolates cause blight or damping off in turfgrasses and seedlings of agriculturally important crops, such as wheat and tomato. Because these pathogens are eukaryotic, it can be difficult to control and prevent infection by Pythium. This work addresses the inhibitory effects of CuO and ZnO nanoparticles (NPs) and Pseudomonas chlororaphis O6 (PcO6) on two strains of a significant oomycete. Pythium ultimum was obtained from the American Type Culture Collection originally from diseased wheat, and Pythium aphanidermatum was isolated from diseased tomato plants. Both CuO and ZnO nanoparticles caused dose-dependent reductions in radial growth of these isolates on potato dextrose agar: P ultimum was more sensitive to inhibition by CuO NPs than P aphanidermatum. Growth inhibition also occurred in potato dextrose broth. Transfer of the mycelium from broth to plate medium showed that the NPs were not biocidal but caused stasis: CuO NPs were more inhibitory than the ZnO NPs. A soil-borne pseudomonad, isolate PcO6, also significantly reduced the radial growth of Pythium; inhibition also occurred when compounds secreted from PcO6 were added to growth medium. Thus both the chemical treatments with NPs and the biological control with PcO6 could be integrated into strategies to afford protection for seedlings from pathogen attack.

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