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

Dendrogram Based Dendrogram Based on FAME Analysison FAME Analysis

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