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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Crop Bioprotection Research » Research » Publications at this Location » Publication #292849

Title: Tracking native and applied populations of Cryptococcus flavescens in the environment

item RONG, XIAOQUING - The Ohio State University
item ROTONDO, FRANCESCA - The Ohio State University
item Schisler, David
item PAUL, PIERCE - The Ohio State University
item MCSPADDEN GARDENER, BRIAN - The Ohio State University

Submitted to: Plant Gene
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/17/2016
Publication Date: 12/27/2016
Citation: Rong, X., Rotondo, F., Schisler, D.A., Paul, P.A., McSpadden Gardener, B.B. 2016. Tracking native and applied populations of Cryptococcus flavescens in the environment. Plant Gene. doi: org/10.1016/j.plgene.2016.12.004.

Interpretive Summary: A yeast previously discovered at the NCAUR, USDA-ARS biologically controls Fusarium Head Blight, a globally important disease of wheat. In this study, Ohio State University and ARS scientists developed a molecular-biology-based technique to quantify population dynamics of this yeast and successfully tested it on field grown wheat inoculated with the biocontrol agent. We discovered that the dispersal of the yeast from inoculation sites increased with time and that the yeast could be detected on harvested grains and postharvest field residue. This breakthrough provides a new tool for understanding the environmental fate of this biocontrol agent and how its population on wheat relates to biocontrol effectiveness. Such information is crucial to the development of this environmentally benign yeast as a commercial biocontrol product to benefit wheat producers, processors, and consumers.

Technical Abstract: Cryptococcus flavescens strain OH182.9_3C (3C) exhibits biological control efficacy against Fusarium Head Blight, a globally important disease of wheat. In this study, a quantitative PCR (qPCR) assay of SYBR® Green chemistry targeting a Heat Shock Protein 70 kDa gene was developed and applied to monitor the population dynamics of 3C-like C. flavescens in wheat fields and on harvested grains. qPCR results demonstrated that 3C was able to colonize inoculated wheat heads in field at the magnitude of 10E+4.5 to 10E+6.5 target gene copies per gram wheat, which was comparable to the inoculation rates. 3C population dispersed from inoculated areas to non-inoculated areas in a stochastic fashion during the growing season. Neither human activity of sample collection or prevailing wind direction played a significant role in 3C dispersal. Population of 10E+2.5 to 10E+5.5 copies/g was detected on postharvest residues in inoculated areas during the winter and spring following the growing season, and higher population was detected on non-rotting wheat stalks than on other major components of residues. 3C population died off on harvest grains from around 10E+3.5 copies/g to below the detection limit for non-inoculated samples. This study presents the successful development and application of a qPCR assay that gave meaningful results on the dispersal and persistence patterns of 3C on field-grown wheat. The assay can be used to assess the environmental fate and risk of 3C as an active ingredient of biopesticide and to study the ecological behavior of 3C relevant to its biocontrol activities.