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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Plant Pathology Research » Research » Research Project #442004

Research Project: Mitigation of Domestic, Exotic, and Emerging Diseases of Subtropical and Temperate Horticultural Crops

Location: Subtropical Plant Pathology Research

2022 Annual Report

Objective 1: Characterize ecology, biology, and epidemiology of domestic, exotic, newly emerging, and re-emerging pathogens of horticultural crops. (NP303, C1, PS1A; C2, PS2A, PS2B, PS2C, PS2D) 1.A: Characterize the basic biology of ‘Candidatus Liberibacter asiaticus (Las),’ the bacterium associated with citrus huanglongbing (HLB) by in vitro culture, and characterize new seed-transmissible diseases of citrus. 1.B: Characterize the basic biology, molecular biology, vector interactions and/or epidemiology of orthotospoviruses, Xanthomonas fragariae [cause of angular leaf spot (ALS) on strawberry] and other pathogens of vegetables, citrus, ornamentals, and weeds. Objective 2: Develop and improve reliable detection and sampling methods for pathogens of subtropical and temperate horticultural crops. (NP303, C1, PS1A, PS1B) 2.A: Develop and/or improve detection and sampling methods for orthotospoviruses, Las and Xanthomonas fragariae on strawberry. 2.B: Train canines to detect thrips-transmitted TCSV and whitefly-transmitted SqVYV. Objective 3: Develop or improve comprehensive integrated disease management strategies to mitigate existing or emerging diseases of horticultural crops. (NP303, C3, PS3A, PS3B) 3.A: Develop and implement the most efficacious strategies for disease management of HLB, Xanthomonas fragariae on strawberry, fungal foliar diseases on cucurbits, and viruses of vegetables and ornamentals. 3.B: Develop new and/or augment existing surveillance methods and protocols for HLB and other new citrus diseases, and areawide management of insect-vectored viral diseases of vegetables.

The overall approach is to thoroughly characterize plant pathogens causing domestic, exotic and emerging diseases at multiple levels: cellular, molecular and/or biochemical levels of host-pathogen-vector interaction and traditional and newer stochastic epidemiological analysis at field and regional levels. New pathogens will be identified and characterized by biological and traditional cultural methods. Recombinant DNA and genomics technologies will be applied to study host-pathogen interactions. Resulting knowledge will be used to develop new detection and sampling methods, and management strategies, for these pathogens.

Progress Report
Work on all objectives commenced with the new project plan in late March 2022 and ARS scientists at Fort Pierce, Florida, are making progress expected to put us on track for fully meeting all of our milestones after the first complete year of the project. Liberibacter asiaticus basic and molecular biology, and genetic characterization, has continued from the previous project. Citrus, vegetable and strawberry pathogen surveys, and meteorological data compilation have been initiated. Virus and bacteria detection assay development initiated and canine detection trials have continued. Management trials and collection of spatial distribution data and development of epidemic models have continued.


Review Publications
Gautam, S., Mugerwa, H., Buck, J.W., Dutta, B., Coolong, T., Adkins, S.T., Srinivasan, R. 2022. Differential transmission of Old and New World begomoviruses by Middle East Asia Minor 1 (MEAM1) and Mediterranean (MED) cryptic species of Bemisia tabaci. Viruses. 14:1104.
Yang, C., Powell, C., Duan, Y., Lin, X., Fan, G., Hu, H., Zhang, M. 2022. Key role of heat shock protein expression induced by ampicillin in citrus defense against huanglongbing: a transcriptomics study. Agronomy. 12:1356.
Parajuli, S., Huo, H., Gmitter, F., Duan, Y., Luo, F., Deng, Z. 2022. Editing the CsDMR6 gene in citrus results in resistance to the bacterial disease citrus canker. Horticulture Research. 2.
Mugerwa, H., Gautam, S., Catto, M.A., Dutta, B., Brown, J., Adkins, S.T., Srinivasan, R. 2022. Differential transcriptional responses in two Old World Bemisia tabaci cryptic species post acquisition of old and new World begomoviruses. Cells. 11:13.
Steele, G.C., Rossitto De Marchi, B., Lahiri, S., Adkins, S.T., Turechek, W., Smith, H.A. 2022. The influence of tomato yellow leaf curl virus on dispersal by Bemisia tabaci MEAM1 in tomato. Entomologia Experimentalis et Applicata. 170:744-754.
Turechek, W., Winterbottom, C., Meyer-Jertberg, M., Wang, H. 2022. Survival of Xanthomonas fragariae on common materials. Plant Disease. 106 (in press).