Location: Cereal Disease Lab
2018 Annual Report
Objectives
Additional funds will enhance research on current Objective 2, "Relate fungal genotypes to mycotoxin production in fungal strains in field production environments to aid in developing enhanced methods of control," by expanding coverage for characterization of populations of Fusarium; to current Objective 3, "Optimize metagenomic and functional approaches to define the phytobiome of healthy and diseased plants naturally infested with the FHB fungus," by enhancing the functional characterization of the wheat phytobiome; and to current Objective 4, "Identify novel sources of plant disease resistance to FHB and mycotoxins produced by FHB fungi to improve breeding for resistance," by expanding analysis of FHB resistant populations and efforts to pyramid resistance genes in a given background.
Approach
Improved management strategies are needed to maintain adequate plant disease control. Specific approaches include: 1) Genetic information obtained from the fungal pathogen, Fusarium, will be used to identify genes factors responsible for fungal pathogenesis, possibly leading to novel approaches to control FHB disease and reduce toxin levels in grain; 2) FHB levels, strain diversity, and the nature of associated fungal communities, will be monitored by population genetic and metagenomic approaches improving the ability to forecast the economic impact and the design of effective management strategies; 3) Novel sources of FHB resistance and mycotoxin tolerance will be developed for plants.
Progress Report
In the first full year of the project, USDA-ARS scientists located in St. Paul, Minnesota have made substantial progress on the following Objectives: Objective 1.A. Created deletion mutants of the Fusarium Tri14 gene and introduced them into several genetic backgrounds that allow for examination of the fungal ER. Initial fluorescent energy transfer of toxisomes has been conducted; Objective 1.B. Completed three RNAseq experiments of Fusarium graminearum during toxin synthesis; Objective 2. Surveys of the FHB pathogen are currently ongoing, both from wheat and native grass species; Objective 3. Characterizing interactions of Fusarium and soil microbes for potential antagonistic interactions; Objective 4. Created populations of durum wheat segregating for disease resistance and developed a radiation hybrid breeding population.
Accomplishments
1. Tracking down the origins of wheat disease leads to new ideas on prevention. Wheat and barley crops are vulnerable to a disease called Fusarium Head Blight (FHB) which can impact farmers by reducing yield and requiring costly fungicide applications. ARS scientists from St. Paul, Minnesota tracked down the origin of the fungus that causes the costly disease. Remarkably, many native grasses found along highways and hedgerows can harbor the fungus, and unlike the case of crop plants, these native grasses allow the fungus to grow without causing symptoms of FHB. While the non-symptomatic plants potentially could be a reservoir of the harmful fungus, a more exciting prospect is that the plants themselves may contain genes for tolerance to the fungus and resistance to the disease it causes.
Review Publications
Lofgren, L., Riddle, J.M., Dong, Y., Kuhnem, P.R., Cummings, J.A., Del Ponte, E.M., Bergstrom, G.C., Kistler, H.C. 2017. A high proportion of NX-2 mycotoxin producing strains are found among Fusarium graminearum isolates from northeastern New York State. European Journal of Plant Pathology. 150:791-796.
Deiuilo, G.A., Guo, L., Zhang, Y., Goldberg, J.M., Kistler, H.C., Ma, L. 2018. Kinome expansion in the Fusarium oxysporum species complex driven by accessory chromosomes. mSphere. 3(3):e00231-18. https://doi.org/10.1128/mSphere.00231-18.
Tang, G., Chen, Y., Xu, J., Kistler, H.C., Ma, Z. 2018. The fungal myosin I is essential for Fusarium toxisome formation. PLoS Pathogens. 14(1):e1006827. https://doi.org/10.1371/journal.ppat.1006827.
Lofgren, L.A., LeBlanc, N.R., Certano, A.K., Nachtigall, J., Labine, K.M., Riddle, J.M., Dong, Y., Broz, K.L., Bethan, B., Kafer, C.W., Kistler, H.C. 2018. Fusarium graminearum: Pathogen or endophyte of North American grasses? New Phytologist. 217(3):1203-1212. https://doi.org/10.1111/nph.14894.
LeBlanc, N.R., Essarioui, A., Kinkel, L.L., Kistler, H.C. 2017. Phylogeny, plant species, and plant diversity influence carbon use phenotypes among Fusarium populations in the rhizosphere microbiome. Phytobiomes Journal. 1(3):150-157. https://doi.org/10.1094/pbiomes-06-17-0028-r.
