致病桿菌屬的系統(tǒng)進(jìn)化及其兩個新種的描述.pdf

1、中山大學(xué)碩士學(xué)位論文致病桿菌屬的系統(tǒng)進(jìn)化及其兩個新種的描述姓名：白麗吉申請學(xué)位級別：碩士專業(yè)：微生物學(xué)指導(dǎo)教師：邱禮鴻20100610SystematiesofXenorhabdusandDescriptionofTwoNewSpeciesofXenorhabdusMajor：MicrobiologyName：BrigittePoolSupervisor：ProfessorQIULihongAbstractMembersofXenorh

2、abdus，whichcomprisesof21speciescurrentlyalesymbiontsofentomopathogenicnematodesofthegenusSteinernemaThey珊gramnegativebacteriabelongingtothefamilyEnterobacteriaceaeandareknowntoproduceavarietyofbioactivemetabolitessuch嬲in

3、secticidaltoxinsandantibioticsThenematode—bacteriumassociationislliglllytoxictoa、)I『iderangeofinsectsandprovidesanefficientbiologicalcontrolformanyimportantcropsInthepresentstudythephylogeneficrelationshipofXenorhabduswi

4、thinthefamilyEnterobacteriaceaewereanalyzedbased01116SrDNAsequencesandbiochemicalpropertiesPhylogenetictreescomprisingof67speciesfrom45generaofthefamilyEnterobacteriaceaewereconstructedbytheneighbourjoiningandmaximumpars

5、imonymethodsRegardlessofthephylogeneticmethodusedXenorhabdusWaslocatednearthebaseofthetreeandclusteredwithPhotorhabdusanothergenusofthesymbioticbacteriaofentomopathogenicnematodesTwostrainsofsymbioticbacteriaYNc215andYNd

6、393isolatedfromlocallycoUectedinfectivejuvenilesofSteinernemasppWerealsodescribedbyapolyphasicapproachcomprisingofmolecular(16SrDNAandgyrBgenesequence)andphenotypiccharacterizationPhylogeneticanalysisof16SrDNAsequencespl

7、acedthetwostrainsinthegenusXenorhabdusPhylogenetictreesandgeneticdistanceanalysisbasedOil16SrDNAandgyrBgenesequencesshowedthatYNc215andYNd393a托newspeciesofXenorhabduswhicha把closelyrelatedtoXindicaandXehlersiirespectively

8、ThephenotypicpropertiesofthetwoisolatesdifferedfromotherdescribedtypestrainsofthegenusXenorhabdusincludingtheircloselyrelatedspeciesBothmolecularandphenotypicanalysissuggestcongruentlythatYNc215andYNd393representtwonewsp