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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 #297642

Title: Genotypic and phenotypic characterization of Cryptococcus flavescens, beneficial biocontrol agents for controlling Fusarium head blight of wheat

item RONG, XIAOQING - The Ohio State University
item Schisler, David
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: 12/23/2016
Citation: Rong, X., Schisler, D.A., McSpadden Gardener, B.B. 2016. Genotypic and phenotypic characterization of Cryptococcus flavescens, beneficial biocontrol agents for controlling Fusarium head blight of wheat. Plant Gene. doi: org/10.1016/j.plgene.2016.12.003.

Interpretive Summary: Cryptococcus flavescens strain OH182.9_3C is a yeast previously co-discovered by ARS scientists in Peoria, IL at the NCAUR, USDA-ARS and scientists at The Ohio State University. This yeast biologically controls Fusarium Head Blight (FHB), a globally important disease of wheat. In this study, Ohio State University and ARS scientists determined, after characterizing the genomes of multiple isolates of C. flavescens, that 5 areas within the genetic code of the strains consistently revealed two genotypes; A (6 strains, including 3C) and B (7 strains). Genotypes A and B strains were of opposite mating types and interestingly, genotype A strains were slightly more effective in reducing Fusarium head blight in greenhouse assays. This discovery will allow strains of C. flavescens to be rapidly characterized for biocontrol potential via genotyping and enhance the likelihood of discovering additional biocontrol agents for development as biocontrol products that reduce the impact of FHB on wheat producers, processors, and consumers.

Technical Abstract: Cryptococcus flavescens strain OH182.9_3C (3C) previously displayed significant biological control activity against Fusarium head blight, a globally important disease of wheat; however, the diversity within C. flavescens has not been previously characterized. Multilocus sequence typing was performed on strain 3C and 12 other C. flavescens strains using six apparently unlinked loci: rDNA-ITS, ß-tubulin, chitin Synthase 1, elongation factor 1, heat shock protein 70 kDa and a mostly anonymous region. The rDNA-ITS sequences were identical across all the 13 strains. The other five loci consistently revealed two genotypes, A (6 strains, including 3C and type strain NRRL Y-1401T) and B (7 strains), with high bootstrap support. This genotypic split was congruent to the mating type previously performed on some of the tested strains. Phenotypic variation noted using Biolog assays supported the grouping by genotype and revealed the slow assimilation of several carbon sources by two isolates of genotype A. In green house bioassays, the strains of both genotypes showed biocontrol efficacy against Fusarium head blight, but genotype A as a whole showed slightly greater biocontrol efficacy than genotype B strains. This study provided insight into the phylogenetic relationships within C. flavescens species and resources for developing genetic and phenotypic markers to differentiate subspecies of C. flavescens.