简介：Severalbacterialstrainswereisolatedfromdifferentrhizospheres.Amongthese,strainPDY7exhibitedstrongantibacterialactivityagainstthericebacterialblight(BB)pathogenXanthomonasoryzaepv.oryzae(Xoo)bythelaboratorydualplateassays.TheantibacterialpropertyofthestrainPDY7wasfurtherinvestigatedfortheproductionof2,4-diacetylphloroglucinol(DAPG),whichamplifiedacharacteristicof629-bpDNAfragmentbyPCR-basedscreeningmethodusingphlDprimers.TheapplicationofphlDpositivestrainswascarefullyevaluatedfordiseasecontrolandgrowthpromotionofriceplantsunderfieldconditions.TheselectedstrainPDY7suppressedthericeBBby58.83%and51.88%underglasshouseandfieldconditions,respectively.Inaddition,thestrainPDY7showedsignificanttwo-foldincreaseinrootlength(18.08cm),shootlength(29.81cm),andgrainyield(96.07g).StrainPDY7promotedthegrowthofriceplantsbyproductionofindole-3-aceticacid(IAA),whichwasdeterminedbyhighperformanceliquidchromatography(HPLC)analysis.OurfindingssuggestthatPDY7belongstotheP.fluorescensgroupandcanserveaspotentialbiocontrolofBBaswellasbiofertilizeragentforgrowthpromotionofrice.

简介：Plantassociatedbacteriaarepromisingalternativestochemicalfertilizersforplantgrowthandyieldimprovementinaneco-friendlymanner.Inthisstudy,riceassociatedbacteriawereisolatedandassessedformineralphosphatesolubilizationandindole-3-aceticacid(IAA)productionactivityinvitro.Sixpromisingstrains,whichweretentativelyidentifiedasphylotaxonPseudochrobactrumsp.(BRRh-1),Burkholderiasp.(BRRh-2),Burkholderiasp.(BRRh-3),Burkholderiasp.(BRRh-4),Pseudomonasaeruginosa(BRRh-5andBRRh-6)basedontheir16SrRNAgenephylogeny,exhibitedsignificantphosphatesolubilizingactivityinNationalBotanicalResearchInstitutephosphategrowthmedium,andBRRh-4displayedthehighestphosphatesolubilizingactivity,followedbyBRRh-5.ThepHoftheculturebrothdeclined,resultinginincreaseofgrowthrateofbacteriaatpH7,whichmightbeduetoorganicacidsecretionbythestrains.InpresenceofL-tryptophan,fiveisolatessynthesizedIAAandthemaximumIAAwasproducedbyBRRh-2,followedbyBRRh-1.ApplicationoftwomostefficientphosphatesolubilizingisolatesBRRh-4andBRRh-5byrootdipping(colonization)ofseedlingandsprayingatthefloweringstagesignificantlyenhancedthegrowthandgrainyieldofricevarietyBRRIdhan-29.Interestingly,applicationofbothstrainswith50%ofrecommendednitrogen,phosphorusandpotassiumfertilizersproducedequivalentorhighergrainyieldofricecomparedtothecontrolgrownwithfullrecommendedfertilizerdoses,whichsuggeststhatthesestrainsmayhavethepotentialtobeusedasbioinoculantsforsustainablericeproduction.

简介：Itisnecessarytounderstandthebacterialpopulationsassociatedwithricesoastoprovidemoreinformationandnaturalresourcesforeffectivemanagementofmajordiseasesinrice.Asurveyonscreeningandidentificationofgram-positivebacteriawasconductedduring1998-2004.Sevenhundredandfifty-sixricesampleswerecollectedfromZhejiang,Jiangsu,FujianandYunnanProvinces,China.Over1000bacterialisolateswereisolatedandtestedforcolonymorphology,pathogenicity,andsomecharacteristicsofbacteriologyincludingGramstaining,fluorescentpigmentonKingsmediumBandmicroscopicobservationforendospore.Togetherwithfivestandardreferencestrains,74representativegram-positivebacterialisolateswereconfirmedbyBiologandgaschromatographicanalysisoffattyacidmethylesters.FivebacterialspeciesofBacillusandotherthreegenerawereidentifiedandisolatesfromBacillussublitisandBacillusmegaterium,exhibitedthemosteffectiveinhibitionagainstthepathogensofsheathblightandbakanaediseaseofrice.AfewisolatesfromBacilluspumilusandBacillusmegateriumshowedweakvirulentonricetogetherwithsomevirulentisolates,dskshouldbeconsideredwhenisolatesfromthesespecieswerescreenedforbiocontrolagents.