SeedborneSeedborne TransmissionTransmission ofof ClubrootClubroot ofof CrucifersCrucifers ResearchResearch Team:Team: S.E.S.E. StrelkovStrelkov,, R.J.R.J. HowardHoward andand S.F.S.F. HwangHwang GraduateGraduate Student:Student: D.C.D.C. RennieRennie OutlineOutline ofof PresentationPresentation •• IntroductionIntroduction andand backgroundbackground •• StudyStudy objectivesobjectives •• DetectionDetection ofof seedseed infestationinfestation levels,levels, naturalnatural infestationinfestation ofof seedsseeds andand tuberstubers •• EffectsEffects ofof seedseed cleaningcleaning •• EvaluationEvaluation ofof seedseed treatmentstreatments •• ConclusionsConclusions ClubrootClubroot SpreadSpread •• SoilborneSoilborne pathogenpathogen 7 8 •• MovementMovement ofof infestedinfested 0.169 0.155 soilsoil 6 9 0.296 0.225 – Machinery 150 m 150 m – Soil erosion and water 3 4 2 5 run-off 0.324 0.310 •• PossibilityPossibility forfor 0.394 0.479 transmissiontransmission ofof restingresting 150 m 150 m sporesspores asas seedborneseedborne 1 Field Entrance contaminants?contaminants? 0.901 Frequency of infection SeedborneSeedborne ClubrootClubroot TransmissionTransmission •• ManyMany nonnon--refereedrefereed factfact--sheetssheets && websiteswebsites mentionmention thisthis possibilitypossibility butbut provideprovide nono datadata •• LittleLittle informationinformation availableavailable inin refereedrefereed literatureliterature –– WarneWarne (1943):(1943): introductionintroduction ofof clubrootclubroot toto aa gardengarden onon infestedinfested seedsseeds –– HazraHazra etet al.al. (1998):(1998): presencepresence ofof drieddried rootroot fragmentsfragments mixedmixed withwith seedsseeds •• LargeLarge gapgap inin knowledgeknowledge onon thisthis topictopic StudyStudy ObjectivesObjectives •• EvaluateEvaluate riskrisk posedposed byby seedborneseedborne transmissiontransmission ofof clubrootclubroot •• AssessAssess thethe efficacyefficacy ofof seedseed cleaningcleaning && treatmentstreatments •• DevelopDevelop recommendationsrecommendations forfor growersgrowers && industryindustry SupportSupport obtainedobtained fromfrom thethe CSGA,CSGA, ACPC/ACIDFACPC/ACIDF && industryindustry partners;partners; currentlycurrently justjust pastpast ½½ wayway pointpoint ofof thethe researchresearch DetectionDetection ofof SeedSeed InfestationInfestation LevelsLevels •• CouldCould detectdetect asas littlelittle No. resting spores per seed asas oneone restingresting sporespore M 106 105 104 103 102 101 1 0 C perper canolacanola seedseed – Artificially inoculated seedlots •• HowHow manymany sporesspores areare neededneeded toto causecause disease?disease? SeedSeed InfestationInfestation LevelLevel && ClubrootClubroot SeveritySeverity •• UnderUnder greenhousegreenhouse conditions,conditions, eveneven tracetrace levelslevels ofof infestationinfestation couldcould causecause somesome clubrootclubroot – Optimal conditions for the pathogen EvidenceEvidence ofof NaturalNatural SeedSeed InfestationInfestation •• TestedTested farmerfarmer-- Dust Dust Wheat Wheat Wheat Wheat Canola Canola M +C Canola -C M +C Canola -C harvestedharvested seedsseeds ofof variousvarious cropscrops forfor thethe presencepresence ofof P.P. brassicaebrassicae inoculuminoculum •• FoundFound onon canola,canola, wheat,wheat, ryerye && barleybarley •• WhatWhat aboutabout potatoes?potatoes? InfestationInfestation onon PotatoPotato TubersTubers •• FourFour varietiesvarieties ofof potatoespotatoes growngrown inin clubrootclubroot--infestedinfested fieldfield variety inin southernsouthern AlbertaAlberta 1 2 3 4 •• SubjectedSubjected toto PCRPCR testingtesting •• PresencePresence ofof P.P. brassicaebrassicae DNADNA detecteddetected QuantificationQuantification ofof InoculumInoculum LevelsLevels •• DevelopedDeveloped quantitativequantitative PCRPCR techniquetechnique toto quantifyquantify DNADNA levelslevels andand relationshiprelationship toto sporespore levelslevels andand clubrootclubroot severityseverity – Validation through bioassays Standard curve of average CT values plotted against Log2 of serial dilution of spore DNA EffectEffect ofof SeedSeed CleaningCleaning •• ExaminedExamined cleanedcleaned seedsseeds ofof numerousnumerous cropscrops – Seed cleaning plant in clubroot epicenter – No information on whether seedlots came from clubroot fields, or whether they were infested prior to cleaning Rye G. pea Rye G. pea Wheat Y. pea Barley Wheat Wheat Barley G. pea Y. pea Barley Wheat Wheat Y. pea Barley Wheat Wheat Barley G. pea Y. pea Barley Oat Wheat M +C Oat -C NaturallyNaturally InfestedInfested SeedsSeeds •• NaturallyNaturally infestedinfested seedsseeds && detectiondetection ofof P.P. brassicaebrassicae afterafter seedseed cleaningcleaning suggestsuggest smallsmall riskrisk ofof seedborneseedborne transmissiontransmission –– SecondarySecondary toto movementmovement onon equipmentequipment –– RoleRole inin disseminationdissemination toto otherother regions?regions? FastFast disseminationdissemination ofof pathotypes?pathotypes? •• ToTo furtherfurther reducereduce anyany riskrisk andand allayallay concerns,concerns, seedseed treatmentstreatments representrepresent attractiveattractive optionoption EvaluationEvaluation ofof SeedSeed TreatmentsTreatments Dynasty Seed & soilborne diseases •• FungicidesFungicides commonlycommonly Prosper FX Seed rot, usedused asas seedseed damping-off, early Prosper 400 root rot, seedling treatmentstreatments blights, seedborne diseases, •• FungicideFungicide effectiveeffective insecticide againstagainst P.P. brassicaebrassicae,, Vitavax RS Seed rots, powderypowdery scabscab damping-off, seedling blights, early root rot Helix Xtra Seed & soilborne ThisThis researchresearch isis currentlycurrently diseases, underwayunderway insecticide Nebijin Potato powdery scab, clubroot on Brassicas ConclusionsConclusions •• SeedborneSeedborne transmissiontransmission ofof clubrootclubroot isis possiblepossible andand couldcould bebe aa secondarysecondary modemode ofof diseasedisease spreadspread •• LowLow--levelslevels ofof infestationinfestation enoughenough toto induceinduce somesome diseasedisease –– ConduciveConducive conditionsconditions probablyprobably requiredrequired •• SeedSeed cleaningcleaning maymay helphelp reducereduce riskrisk butbut notnot eliminateeliminate itit completelycompletely •• EfficacyEfficacy ofof seedseed treatmentstreatments isis beingbeing studiedstudied AcknowledgmentsAcknowledgments •• CanadianCanadian SeedSeed GrowersGrowers’’ AssociationAssociation •• AlbertaAlberta CanolaCanola ProducersProducers CommissionCommission •• AlbertaAlberta CropCrop IndustryIndustry DevelopmentDevelopment FundFund •• EnCana,EnCana, HarvestHarvest EnergyEnergy Trust,Trust, EnerplusEnerplus ResourcesResources CorporationCorporation •• V.V. ManoliiManolii,, T.T. Cao,Cao, M.M. HartmanHartman andand D.D. OrchardOrchard.