Location: Food Quality Laboratory
2022 Annual Report
Objectives
Objective 1: Identify key genes regulating virulence and toxin production in Penicillium species, the causal agents of blue mold, to develop novel gene or protein targets for control in commercially stored pome fruit.
Sub-objective 1.A: Identify new Penicillium spp. virulence and toxin biosynthetic genes via comparative genomics and transcriptomics.
Sub-objective 1.B: Characterize fungal virulence and toxin genes in Penicillium spp. using a targeted gene deletion approach.
Objective 2: Integrate genomic-based strategies and evaluate novel tools to manage postharvest blue mold decay in commercial storage caused by Penicillium species on pome fruit.
Sub-objective 2.A: Determine difenoconazole baseline sensitivity and characterize resistant blue mold isolates.
Sub-objective 2.B: Identify Penicillium spp. genes associated with difenoconazole resistance and develop a molecular-based detection system.
Approach
Multiple approaches are outlined in this project that encompass both basic and applied methodologies to maintain pome fruit quality, deliver effective strategies to manage blue mold decay, and eliminate mycotoxins from processed pome fruit products. Comparative genomics and transcriptome sequencing will be used to discover new fungal virulence genes and pathways that regulate Penicillium spp. virulence, and toxin production to develop pathogen-specific management strategies. Additionally, mechanisms of postharvest fungicide resistance in Penicillium spp. will be determined using a genomics approach to develop molecular-based management tools for producers. Our applied research focus will utilize standard microbiological methods to determine baseline sensitivity to a new postharvest fungicide currently used to manage blue mold decay and will help producers monitor future shifts in sensitivity indicative of resistance. Characterization of fungicide-resistant isolates will provide practical information on the viability and persistence of such isolates in the packing and storage environments and their impact on control using currently available chemical tools labeled for pome fruits. Results from the current study will also guide growers in making decisions for use of the most efficacious fungicides to control blue mold.
Progress Report
This is a new project that was recently certified in April 2022 by USDA-ARS OSQR. We have made significant progress on both Objectives 1 and 2 that deal with fundamental and applied aspects of blue mold control of apple fruit. For the first Objective, we have built 9 gene deletion vectors and have protoplasts prepared for fungal transformation. We are set up and ready to perform the transformations once we move into our new lab space. For the second Objective, we have tested different strains of Penicillium spp. in vivo, quantified their toxin profiles using LC/MS, and have sequenced and assembled their genomes. We have tested different storage bin materials for their ability to bind blue mold spores and determined both organic and conventional means of sanitizing bin surfaces to reduce postharvest blue mold decay.
Accomplishments
1. Cell Phone App to Track Tree Fruit Pests. Tree fruit diseases and pests cause food loss and occur during storage and in the field. ARS researchers in Beltsville, Maryland, in collaboration with Partnerships in Data Innovation and numerous university scientists, developed, tested, and launched a new cell phone app and dashboard to record, map and track diseases of tree fruits. The publicly available tool (PATHMAP) can help inform stakeholders and customers on specific regions and hosts that have outbreaks to help manage pests. Thus, this tool will assist in diagnosis and pest management to reduce their spread locally and globally as fruit are exported to other countries.
Review Publications
Bartholomew, H.P., Bradshaw, M., Macarisin, O., Gaskins, V.L., Fonseca, J.M., Jurick II, W.M. 2022. More than just a virulence factor: patulin is a non-host specific toxin requiring active efflux for auto-avoidance in Penicillium spp. and inhibits growth of multiple postharvest fungal pathogens. Toxins. 112:1165-1174. https://doi.org/10.1094/PHYTO-09-21-0371-R.
Yin, G., Zhang, Y., Pennerman, K.K., Jurick II, W.M., Fu, M., Bu, L., Hua, S.T., Guo, A., Bennett, J.W. 2021. Genomic analyses of Multiple Penicillium species revealed diverse mycotoxin gene clusters and novel loci mediating oxylipin synthesis involved in volatile signaling. The Journal of Fungi. 7(9):743. https://doi.org/10.3390/jof7090743.
Bradshaw, M., Bartholomew, H., Lichtner, F., Gaskins, V.L., Jurick II, W.M. 2021. First report of blue mold caused by Penicillium polonicum on apple in the United States. Plant Disease. https://doi.org/10.1094/PDIS-06-21-1136-PDN.
Bradshaw, M., Bartholomew, H., Hendricks, D., Maust, A., Jurick II, W.M. 2021. A global analysis of postharvest fungal pathogens reveals temporal-spatial and host-pathogen associations linked with FRAC1 fungicide resistance. Phytopathology. https://doi.org/10.1094/PHYTO-03-21-0119-R.
Zebeljan, A., Duduk, N., Vuckovic, N., Jurick II, W.M., Vico, I. 2021. Incidence, speciation, and morpho-genetic diversity of penicillium spp. causing blue mold of stored pome fruits in Serbia. The Journal of Fungi. 7(12):1019. https://doi.org/10.3390/jof7121019.
