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dc.contributor.advisorFletcher, Jacqueline
dc.contributor.authorMoncrief, Ian Russell
dc.date.accessioned2015-06-17T20:07:10Z
dc.date.available2015-06-17T20:07:10Z
dc.date.issued2014-07
dc.identifier.urihttps://hdl.handle.net/11244/15022
dc.description.abstractGlobalization of agricultural commerce increases the vulnerability of the United States to introductions of plant pathogens by inadvertent or intentional means. Plant pathogen forensics combines traditional plant pathology and microbial forensics to enhance crop biosecurity. This research was designed to test and validate microbial forensic tools for plant pathogens in laboratory and field settings. A real-time PCR assay developed by the National Bioforensic Analysis Center for high consequence human pathogens was adapted and validated for the phytopathogenic bacterium, Xylella fastidiosa, which affects many plant species. PCR primers amplified genomic DNA from multiple strains of the bacterium and did not amplify near-neighbor microorganisms or animal or plant DNA. Other forensic tools were developed to investigate an actual outbreak, in Israel, of salmon blotch disease of onions, caused by the phytopathogenic fungus Fusarium proliferatum. A decision tool designed to assist first responders recognize signs of criminal activity at the field was implemented and a DNA fingerprinting assay using simple sequence repeats (SSRs) to discriminate among different pathogen populations was validated. F. proliferatum was isolated from onion and soil samples from the affected field, nearby agricultural fields and natural vegetation in southern Israel onion production areas. Fungal isolates were obtained also from onion sets (grown in northern Israel and shipped for planting in southern fields), to test a hypothesis that the fungus was disseminated on these sets. SSR analyses revealed that fungal populations from onion sets in northern Israel are genetically distinct from those in southern Israel. F. proliferatum populations from southern field site soils are similar to one another and to those from bulbs at each of four southern fields. By SSR analysis, F. proliferatum isolates from volunteer salt cedars in the onion fields are clonal and indistinguishable from those from the southern field soil and white onion bulbs. The findings suggest that onion sets purchased from northern Israel are not the source of the F. proliferatum causing onion salmon blotch in southern Israel. Furthermore, volunteer weeds, including salt cedar, and previously contaminated field soil could serve as alternative reservoirs for the fungus, from which inoculum could have moved to the onions
dc.formatapplication/pdf
dc.languageen_US
dc.rightsCopyright is held by the author who has granted the Oklahoma State University Library the non-exclusive right to share this material in its institutional repository. Contact Digital Library Services at lib-dls@okstate.edu or 405-744-9161 for the permission policy on the use, reproduction or distribution of this material.
dc.titleValidating forensic tools for crop biosecurity: Case study investigation of salmon blotch of onions in Israel
dc.contributor.committeeMemberMarek, Stephen
dc.contributor.committeeMemberChamplin, Franklin
dc.contributor.committeeMemberOchoa-Corona, Francisco
osu.filenameMoncrief_okstate_0664D_13597.pdf
osu.accesstypeOpen Access
dc.type.genreDissertation
dc.type.materialText
thesis.degree.disciplinePlant Pathology
thesis.degree.grantorOklahoma State University


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