More Related Content Similar to transformationinplants-ppt.pdf Similar to transformationinplants-ppt.pdf (20) transformationinplants-ppt.pdf1. NEW TECHNIQUES IN PLANT-BACTERIUM GENE MANIPULATION FOR
IMPROVING CROP PRODUCTIVITY
Presented by: Kirandip
Kaur
4. All stable transformation methods
consist of three steps:
1. Delivery of
DNA into a single
plant cell.
2. Integration
of the DNA
into the plant
cell genome.
3. Conversion
of the
transformed
cell into a
whole plant.
5. Productionoftransgenicplant
Isolate and clone gene of interest
Add DNA segments to initiate or enhance gene expression
Add selectable markers
Introduce gene construct into plant cells (transformation)
Select transformed cells or tissues
Regenerate whole plants
6. Planttransformationbybiologicalmethod
TheglobalareagrownbyGMcropshasseena100-foldincreasesince1996whenonly
1.7millionhaweregrowntoGMcropsto175.2millionhain2013(James2013).
Agrobacteriuminfectionfollowedbyinvitroplantregenerationremainsthemost
efficienttransformationtechniquewithsomeadvantagesincludingitssimplicity,low
cost,lessgenesilence/cosuppressioneffect,andintegrationoffewercopiesofatarget
gene(Ziemienowicz2014).
Bythismethod,hightransformationefficiencieshavebeenobtainedinthemaincrops,
forexamples,90%inrice(Ozawa2012),57.1%inmaize(Choetal.2014),45.0%inwheat
(Richardsonetal.2014),25.0%inbarley(Martheetal.2015),11.7%insoybean(Liuetal.
2008),and9.7%incotton(Chenetal.2014).
12. Planttransformationbybiologicalmethod
High efficient transformation
system of common wheat
mediated by Agrobacterium using
the immature embryos has been
established recently at the Institute
of Crop Science, Chinese
Academy of Agricultural Sciences.
A stable transformation efficiency
of 20–30% was achieved after
confirmed by histochemical
staining, stripe quick test for bar
gene and Southern blotting
(Ishidaet al. 2015)
Journal of Integrative Agriculture 2015,
14(3): 411–413
13. 1. Gene transfer by microprojectile
bombardment
ThecoceptoftransferingDNA-coatedparticlesdirectlyintocellswasfirst
conceivedbySanfordandco-workersin1984.
Thefirstresultsusingagunpowder-drivendevicetodelivertungsten
microprojectilescoatedwithviralRNAintoonionepidermalcells.
Inthesameyear,microprojectile-mediateddeliveryofplasmidDNAresultedin
theintroductionofaforeigngene,alsoinonioncells.
Thismethodisroutineandreliablewayofproducingtransgenicplants.
14. Gene transfer by microprojectile
bombardment
Themethodreliesonadevicewhichutilizesa
propellingforce,suchascompressedgasor
gunpowder,toaccelerateinert(usuallymetal)
particles(themicroprojectiles),coatedwithDNA,
intotargetcells
Thistechniqueisalsoreferredtoasparticle
bombardment,particlegunmethod,particle
accelerationandBiolistics(Biologicalballistics).
ParticalGun
20. 2. Electroporation of protoplast
Electroporationisbasedontheapplicationofastrongelectricalfieldtoenhance
theformationofporesonthecellmembraneduetoapolarityalteration,caused
bytheelectricalfield
Thatinducesadipolarmomentinsidethecells,andapotentialdifference
throughtheplasmaticmembrane.
Ifthecellisexposedtoahighfrequencyfield,itscellularmembranesuffersa
shortcircuitanditsdipolarmomentgrowsandrotatestowardsthedirectionof
thefield,producingacellularstretchingalongthisdirection,leadingtoa
temporalpermeabilizationofthemembrane.
21. Electroporation of protoplast
Transformationfrequencystronglyeffectedbyseveralphysicalfactorssuchas
pulselength
typeanddurationof theelectricalfield,
transmembranepotentialcreated,
extentofmembranepermeation,
durationofthepermeatedstate
modeanddurationofmolecularflow
globalandlocal(surface)concentrationsofDNA,
formofDNA,toleranceofcellstomembranepermeation
andtheheterogeneityofthecellpopulation
22. Electroporation of protoplast
AveryinterestingmethodbasedonelectroporationisNucleofection™,
developedin1998andintroducedtotheresearchmarketin2001
Ithasbeensuccessfulincancerstudiesandtissueengineering.Nucleofection™is
apatentedcommercialelectroporationsystemdevelopedbyAmaxa,andowned
byLonza.
Thevoltage,frequency,andpulsedurationforeachcelltypearenotdisclosedto
theuser.
Themethodologypermitstotransfectmanydifficult-to-transfectprimarycells,
celllines,andstemcells.
Itwouldbeinterestingtoapplythismethodtoplantandfungalcells.
24. 3.Gene transfer through
microinjection
TransformationthroughmicroinjectionisbasedonintroducingDNAintothecytoplasm
ornucleusbyusingaglassmicrocapillary-injectionpipette
Thisoperationrequiresamicromanipulator.
DuringtheintroductionofDNAintothenucleus,cellsareimmobilizedwithaholding
pipetteandgentlesuction.
Microinjectionismainlyusedforthetransformationoflargeanimalcells.
Itsimportanceforplanttransformationisratherlimitedduetothecharacteristicsof
plantcellwalls,whichcontainathicklayerofligninandcellulose.
Theplantcellwallisabarrierforglassmicrotools.Themethodallowedthe
incorporationnotonlyofDNAplasmidsbutalsoofwholechromosomesintoplantcells
25. Gene transfer through
microinjection
Althoughithasafairlyhigh
transformationfrequency(20–50%),
microinjectionisatimeconsuming
processthatrequiresspecificequipment
andconsiderabletraining.
Thistechniquewasusedtostudythe
cellularfunctionsofplantcellsand
plastidphysiology,e.g.intobaccoand
Viciafaba
26. 4. Vacuum Infiltration
AnotherwaytomediatetheincorporationofAgrobacteriumforgenetic
transformationistoapplyavacuumforacertaintimeperiod.
Physically,vacuumgeneratesanegativeatmosphericpressurethatcausestheair
spacesbetweenthecellsinthemembranetodecreaseallowingthepenetrationof
Agrobacteriumintotheintercellspaces.
Thelongerthedurationandthelowerthepressure,thelessairspacethereis
withintheplanttissue.Thetemperature,pHandtimeofinductionofvirulence
geneshaveadramaticeffectonthefrequencyoftransformation.
27. Vacuum Infiltration
Ithastheadvantageofbeingafastprocedurewithalowsomaclonal variationbecausethere
isnotissuecultureinvolved.
ItsmainlimitationisthatsomestrainsofAgrobacteriumareunabletoinfectcertaincell
types.
VacuuminfiltrationinitiallywasusedfortransformingArabidopsisandapples.
ThefirstfungustransformedwasSaccharomyces cerevisiae.
Themethodhasbeenusedtoproduceaplant-derivedvaccineunderthecurrentGood
ManufacturePracticeregulationsforhumanclinicaltrials.
However,ithasnotbeenappliedfortransformationofbacteriaoranimalcellsduetothe
tumorouscharacteristicofAgrobacterium.
30. P.K. Martins et al. / Biotechnology Reports 6 (2015) 61–
63
Setaria viridis floral-dip: A simple and rapid
Agrobacterium-mediated transformation method
Setariaviridisfloraldiptransformation.(a)
Inflorescencedevelopmentalstage(bootstage)
selectedfortransformation.
(b)SpikesdippedinAgrobacteriumsuspension
insideadesiccatorforvacuum-assisted
Agrobacteriuminfiltration.
(c)Spikescoveredwithplasticbagsafter
infiltrationtokeepmoistenfor24h.
(d)SpikeshowingRFP-expressingimmatureseed.
(e)RFP-expressingmatureseeds.
(f)PCRanalysisofsurvivingplantson
hygromycin-containingmedium
31. 5. Laser microbeams
Lasermicrobeamshavebeenusedtointroducegeneticmaterialsintocells
puncturingself-healingholesintothecellwall.
Completemanipulationbylaserlightallowspreciseandgentletreatmentofcells,
subcellular structures,andevenindividualDNAmolecules;inparticularithas
beenusedinanimalcells.
Itrequiresanadequatelasersystem(likenitrogenlasers,excimerpumpeddye
lasers,ortitanium-sapphirelasers)thatcanbeusedasopticaltweezers,coupled
totheappropriatemicroscope.
Thisisanexpensiveandlaborioustechnique.
32. 6. Ultrasound
Ultrasonicwave-mediatedtransformation,alsoknownassonication,isbasedon
sonoporation(theruptureofcellularmembranesbyacousticwaves).
Itisanon-invasivewaytointroduceDNAmoleculesintocellsviaacoustic
cavitationthattemporarilychangesthepermeabilityofthecellmembrane.
Ultrasoundincreasesthetransfectionefficiencyofanimalcells,invitrotissues
andprotoplastswithspatialandtemporalspecificity.
However,ithasbeenreportedthatultrasoundcandamagethecell,completely
breakingitsmembrane.
Crucialparametersaretheintensity,exposuretime,centralfrequency,thetype
ofapplication(continuousorpulsed),thepulserepetitionfrequency,andthe
dutycycle.
33. 7. Shock-waves
Shock waves are pressure pulses with a peak
positive pressure in the kof 30 to 150 MPa, lasting
between 0.5 and 3 μs, followed by a tensile pulse of
upto-20MPawithdurationof2to20μs.
They are produced by electrohydraulic,
electromagnetic or piezoelectric shock wave
generators.
Theexactmechanismresponsibleforshock
wave-assisted cell permeabilization is still not clear,
but there is evidence that it is due to shock wave-
inducedcavitation
Experimental shock wave
35. 1. Gene transfer by polyethylene
glycol
Thistechnologyisapplicableforprotoplastonly.
Thechemicalusedispolyethyleneglycol.Itstimulatesendocytosisandthereby
causingtheuptakeofDNA.
Inthismethodprotoplastarekeptinpolyethyleneglycol(PEG)solution.
TheconcentrationofPEGusedis15%having8000daltonmolecularweight.
AfterexposureofprotoplaststoexogenousDNAinpresenceofPEGandother
chemicals,PEGisremovedandintactprotoplastarethenculturedtoformcells
withwallsandcoloniesinturn.
36. Gene transfer by
polyethylene glycol
Selectionpressureisthenappliedtogetthetransformants.
Thetransferofgeneacrosstheprotoplastmembranecanbeinitiatedby
anumberofchemicalsofwhichpolyethyleneglycolisthemost
important.
Ithasbecomethemostwidelyusedduetotheavailabilityofsimple
transformationprotocol.
Methodwasdevelopedusingcalciumalginatemicrobeadsto
immobilizeDNAmoleculesincombinationwithpolyethyleneglycol
treatmentalso
37. 2. Silicon carbide mediated
transformation
Siliconcarbidemediatedmethodisalsooneofthetransformationmethodused
totransformplants.
Thismethodisleastcomplicated.Inthistechniquefibresareusedwhichare
singlecrystalsofsilicaorganicmineralslikesiliconcarbidewhichpossessan
elongatedshape,havingadiameterof0.6mmandalengthof10–80mm
Inthismethodsiliconcarbidefibers’areaddedtoasuspensioncontaining
plasmidDNAandplanttissue(immatureembryos,callus,cellcluster).
Itisthenmixedincommercialshakersorinvortex.FibrescoatedwithDNA
penetratetheplantcellwallinthepresenceofsmallholesproducedatthetime
ofcollisionbetweenfibresandplantcells
38. Silicon carbide mediated
transformation
Thisprocessiseasyandquick.Itisnotsoexpensiveandusefulforvariousplant
materials.
Themaindrawbackofthistechniqueislowtransformationefficiency,damageto
cellsnegativelyinfluencingtheirfurtherregenerationcapability,andtheneedof
followingextraordinarilyrigorousprecautionprotocolsduringlaboratorywork.
Asbreathingthefibersin,especiallyasbestosones,canleadtoserioussicknesses.
Siliconcarbidewhisker-mediatedembryogeniccallustransformationofcotton
(GossypiumhirsutumL.)andregenerationofsalttolerantplantswerealso
reported
39. 3. Liposome mediated gene
transfer
Liposomesarecircularlipidmolecules withanaqueous
interiorthatcancarrynucleicacids.
ItencapsulatestheDNAfragmentsandthenadheresto
thecellmembranes andfusewiththemtotransferDNA
fragments.
Thus,theDNAentersthecellandthentothenucleus.It
isaveryefficienttechniqueusedtotransfergenesin
bacterial,animalandplantcells.
Variousreportsontheintegrationofgenesintroducedby
meansof liposomesfollowedbytransgenicplant
regenerationfortobaccoandwheathavebeenpublished
40. 4. Pollen tube pathway method
Thetransformationmethodviapollen-tube
pathwayhasgreatsignificanceinagriculture
molecularbreeding.
Afterpollinationthestyleswerecut.TheDNA
wasthenapplied.
TheDNAreachestheovulebyflowingdownthe
pollen-tube.
Itwasappliedfirsttimeforthetransformation
ofrice[29].Herethetransgenicplantswere
obtainedatremarkablyhighfrequency.
AfterwardPTPwasusedforotherspeciese.g.
wheat,soybean,Petuniahybridaand
watermelon.