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ARS Floral & Nursery Crops Research ARS Floral & Nursery Crops Research InitiativeInitiative
Research on Research on PhytophthoraPhytophthora spp. spp.in South Carolina: 2000-2003in South Carolina: 2000-2003
Steven N. JeffersSteven N. JeffersDept. of Plant Pathology & Dept. of Plant Pathology &
PhysiologyPhysiology
Clemson UniversityClemson University
Clemson, SCClemson, SC
Personnel InvolvedPersonnel Involved
FacultyFaculty Steven N. Jeffers—Assoc. Prof. & Ext. SpecialistSteven N. Jeffers—Assoc. Prof. & Ext. Specialist Melissa B. Riley—Associate Professor, Plant PathMelissa B. Riley—Associate Professor, Plant Path David P. Jacobs--Professor, Computer ScienceDavid P. Jacobs--Professor, Computer Science
TechniciansTechnicians Lynn Luszcz—Research AssociateLynn Luszcz—Research Associate
Graduate StudentsGraduate Students Chun-hang Duan—Ph.D. 2002Chun-hang Duan—Ph.D. 2002 Jessica A. Eisenmann—M.S. 2003 (expected)Jessica A. Eisenmann—M.S. 2003 (expected)
Highlights of AccomplishmentsHighlights of Accomplishments
Potential for rapid identification of Potential for rapid identification of PhytophthoraPhytophthora spp. by spp. by FFatty atty AAcid cid MMethyl ethyl EEster ster (FAME) profile analysis(FAME) profile analysis
Characterization of a population of Characterization of a population of Phytophthora cinnamomiPhytophthora cinnamomi associated with associated with woody ornamental cropswoody ornamental crops
Characterization of populations of Characterization of populations of P. nicotianaeP. nicotianae & & P. palmivora P. palmivora associated with herbaceous associated with herbaceous and selected woody ornamental cropsand selected woody ornamental crops
Maintain permanent culture collectionMaintain permanent culture collection
Peony—aerial blightPeony—aerial blight
Phlox—root rotPhlox—root rot Azalea—root rotAzalea—root rot
Shore Juniper—root Shore Juniper—root rotrot
Floriculture Crops Nursery Crops
PhytophthoraPhytophthora spp. on spp. onOrnamental CropsOrnamental Crops
Serious problems in USA & worldwideSerious problems in USA & worldwideNumerous closely-related species involvedNumerous closely-related species involvedVarious sources of inoculumVarious sources of inoculumAccurate identification essentialAccurate identification essential
extension—diagnosis & managementextension—diagnosis & management research—etiology, ecology, epidemiologyresearch—etiology, ecology, epidemiology
Standard morphological identificationStandard morphological identification not always effective and accuratenot always effective and accurate time-consuming & labor-intensivetime-consuming & labor-intensive
Why FAME Analysis ??Why FAME Analysis ??
Proven technology—widely used for bacteriaProven technology—widely used for bacteriaUtilizes commercial hardware & softwareUtilizes commercial hardware & software
MIDI System—Microbial Identification, Inc.MIDI System—Microbial Identification, Inc.System present and used in many diagnostic System present and used in many diagnostic
labs worldwidelabs worldwideFAME profile database is electronicFAME profile database is electronic
easily modified, shared, transferredeasily modified, shared, transferred30 samples processed at one time30 samples processed at one timeRelatively inexpensiveRelatively inexpensive
Objectives of ProjectObjectives of Project
Investigate effects of culture conditions Investigate effects of culture conditions on the production of fatty acids by on the production of fatty acids by selected species of selected species of PhytophthoraPhytophthora
Develop and standardize methods for Develop and standardize methods for generating fatty acid profiles for generating fatty acid profiles for PhytophthoraPhytophthora spp. spp.
Investigate variability in fatty acid Investigate variability in fatty acid profiles among these speciesprofiles among these species
FAME Identification: SummaryFAME Identification: Summary
Amounts of each FA varied among speciesAmounts of each FA varied among speciesFactors affecting FA production determinedFactors affecting FA production determinedStandard procedure for FAME analysis was Standard procedure for FAME analysis was
developeddevelopedFAME profiles appear to be effective for FAME profiles appear to be effective for
identification of speciesidentification of speciesAFLP analysis supported FAME utilityAFLP analysis supported FAME utility
FAME Identification: Future & FAME Identification: Future & ValueValue
Future ResearchFuture Research confirm utility with additional speciesconfirm utility with additional species construct FAME database with known isolatesconstruct FAME database with known isolates validate database with “unknown” isolatesvalidate database with “unknown” isolates
Value of Research to StakeholdersValue of Research to Stakeholders provide a rapid and inexpensive procedure for provide a rapid and inexpensive procedure for
identification to diagnostic labs worldwideidentification to diagnostic labs worldwide expedite studies on management of expedite studies on management of
Phytophthora diseasesPhytophthora diseases
Why Characterize Pathogen Why Characterize Pathogen Populations ??Populations ??
Define morphological & physiological charactersDefine morphological & physiological characters aid in identificationaid in identification sensitivity to mefenoxam & other fungicidessensitivity to mefenoxam & other fungicides
Occurrence & distribution of mating typesOccurrence & distribution of mating types potential for genetic variation & adaptationpotential for genetic variation & adaptation
Pathogenicity & virulence Pathogenicity & virulence identify new hosts, expand known host rangeidentify new hosts, expand known host range determine relative virulencedetermine relative virulence
Ultimately—better disease managementUltimately—better disease management
Population of Population of Phytophthora Phytophthora cinnamomicinnamomi
Predominant species attacking nursery cropsPredominant species attacking nursery crops51 isolates primarily from woody plants in SC51 isolates primarily from woody plants in SC
recovered between 1995 & 2000 by PP Clinicrecovered between 1995 & 2000 by PP Clinic49 isolates A2 & 2 isolates A149 isolates A2 & 2 isolates A1All isolates sensitive to mefenoxamAll isolates sensitive to mefenoxam
ECEC5050 values: 0.04-0.20 mg/L values: 0.04-0.20 mg/L
AFLP analysesAFLP analyses isolates very similar geneticallyisolates very similar genetically implications for sources of inoculum…implications for sources of inoculum…
Population of Population of Phytophthora Phytophthora nicotianaenicotianae
Predominant species attacking bedding Predominant species attacking bedding plants, herbaceous perennials, plants, herbaceous perennials, BuxusBuxus spp. spp.
108 isolates collected in SC during 1995-2000108 isolates collected in SC during 1995-2000Both A1 & A2 mating types presentBoth A1 & A2 mating types present
A2 most commonA2 most commonSome isolates resistant to mefenoxam Some isolates resistant to mefenoxam
ECEC5050 values = 300-700 mg/L values = 300-700 mg/L
29 potentially new hosts under investigation29 potentially new hosts under investigationVirulence among isolates appears to differVirulence among isolates appears to differ
Potential “New” Hosts for Potential “New” Hosts for P. P. nicotianaenicotianae
AgapanthusAgapanthus AruncusAruncus Ceratostigma Ceratostigma
plumbaginoidesplumbaginoides DelospermaDelosperma GauraGaura HemerocallisHemerocallis Hibiscus syriacusHibiscus syriacus KniphofiaKniphofia LamiumLamium
PenstemonPenstemon PetuniaPetunia Phlox paniculataPhlox paniculata RodgersiaRodgersia SalviaSalvia x x superbasuperba SedumSedum TiarellaTiarella Vinca minorVinca minor ViolaViola x x
wittrockianawittrockiana
New hosts for New hosts for P. P. nicotianaenicotianae
Sedum—root rotPetunia—root rotPetunia—root rot
Population of Population of Phytophthora Phytophthora palmivorapalmivora
Previously not found on ornamental crops in Previously not found on ornamental crops in the Southeastthe Southeast
Primarily attacks Primarily attacks HederaHedera spp. & spp. & Fatsia Fatsia japonicajaponica both in the family Araliaceaeboth in the family Araliaceae
38 isolates collected in SC during 1995-200038 isolates collected in SC during 1995-2000Morphologically similar to Morphologically similar to P. nicotianaeP. nicotianaeOnly A1 mating type foundOnly A1 mating type foundAll isolates very sensitive to mefenoxam All isolates very sensitive to mefenoxam
ECEC5050 values < 0.10 mg/L values < 0.10 mg/L
Pathogen Populations: Future & Pathogen Populations: Future & ValueValue
Future ResearchFuture Research compare populations from ornamental crops to compare populations from ornamental crops to
those from natural ecosystemsthose from natural ecosystems determine virulence of isolates from different determine virulence of isolates from different
populationspopulations identify sources of primary inoculumidentify sources of primary inoculum
Value to StakeholdersValue to Stakeholders identify new host speciesidentify new host species pinpoint sources of inoculumpinpoint sources of inoculum more effective disease management strategies more effective disease management strategies
PhytophthoraPhytophthora Culture Collection Culture Collection
Maintain a collection of 1000+ isolatesMaintain a collection of 1000+ isolates valuable resourcevaluable resource distribute isolates to colleaguesdistribute isolates to colleagues receive isolates from colleaguesreceive isolates from colleagues
Constructing an ACCESS database so Constructing an ACCESS database so information is readily accessibleinformation is readily accessible in cooperation with Dept. of Computer Sciencein cooperation with Dept. of Computer Science will be posted on the webwill be posted on the web
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