觀賞海棠‘王族’無(wú)融合生殖胚胎發(fā)育及分子機(jī)制研究

觀賞海棠‘王族’無(wú)融合生殖胚胎發(fā)育及分子機(jī)制研究摘要：

近年來(lái)，越來(lái)越多的植物基因組數(shù)據(jù)表明，無(wú)融合生殖（Apomixis）是植物進(jìn)化與適應(yīng)環(huán)境的重要途徑。海棠（CrataegusL.）是花卉園藝中廣泛種植的觀賞植物之一，其中“王族”品種由于其極佳的觀賞性能受到了廣泛的關(guān)注。本研究以“王族”品種為研究對(duì)象，從分子層面上闡明了其無(wú)融合生殖胚胎發(fā)育的特點(diǎn)以及發(fā)育機(jī)制。首先，采用組學(xué)方法鑒定了“王族”品種中的無(wú)融合生殖分子標(biāo)記，并結(jié)合轉(zhuǎn)錄組和代謝組數(shù)據(jù)分析，進(jìn)一步深入闡釋了無(wú)融合生殖在“王族”品種中的調(diào)控網(wǎng)絡(luò)。其次，通過(guò)細(xì)胞學(xué)觀察和染色體組學(xué)分析，揭示了“王族”胚胎發(fā)育過(guò)程中的特點(diǎn)以及其與有融合生殖胚胎發(fā)育的差異。最后，結(jié)合轉(zhuǎn)錄因子和信號(hào)通路分析，揭示了“王族”無(wú)融合生殖調(diào)控機(jī)制中的關(guān)鍵基因及其相關(guān)的信號(hào)通路，為海棠無(wú)融合生殖的進(jìn)一步研究提供了一定的參考價(jià)值。

關(guān)鍵詞：海棠；王族；無(wú)融合生殖；胚胎發(fā)育；分子機(jī)制。

Abstract：

Inrecentyears,increasinggenomicdatafromplantshavesuggestedthatApomixisisanimportantpathwayforplantevolutionandadaptationtoenvironment.Asoneofthewidelycultivatedornamentalplantsinhorticulture,CrataegusL.(hawthorns)hasattractedalotofattentionduetoitsexcellentornamentalperformance,especiallythe"royal"cultivars.Inthisstudy,weaimedtoelucidatethecharacteristicsanddevelopmentalmechanismofapomixisinthe"royal"cultivarsofhawthornsatmolecularlevel.Firstly,molecularmarkersofapomixiswereidentifiedinthe"royal"cultivarsbygenomicsapproaches,combinedwithtranscriptomeandmetabolomedataanalysis,theregulationnetworkofapomixisinthe"royal"cultivarswasfurtherexplored.Secondly,theobservationsofcytologyandchromosomalgenomicsanalysisrevealedthecharacteristicsofembryonicdevelopmentandthedifferencesbetweenapomicticandsexualembryonicdevelopment.Finally,thekeygenesandsignalingpathwaysintheregulationofapomixiswereidentifiedbytranscriptfactorsandsignalingpathwayanalysis,whichmayprovidereferencesforfurtherresearchesonapomixisinhawthorns.

Keywords:CrataegusL.;royal;apomixis;embryonicdevelopment;molecularmechanismApomixis,aformofasexualreproduction,isauniqueprocessthatallowsplantstoproduceoffspringwithoutfertilization,resultinginoffspringthataregeneticallyidenticaltotheparentplant.Inhawthorns,apomixisisobservedinsomespeciesandcultivars,andithasbeensuggestedthatapomixiscouldbeusedinbreedingprogramstoproduceplantswithdesirabletraits.

Cytologicalobservationsofhawthornembryosrevealedsomedistinctdifferencesbetweenapomicticandsexualembryonicdevelopment.Inapomicticembryos,thetypicalfertilizationprocessisbypassed,andtheresultingembryodevelopsfromunfertilizedeggcells,resultingintheabsenceofendosperm.Inaddition,apomicticembryostendtodevelopfasterandhaveasimplerembryonicstructurecomparedtosexualembryos.

Togainadeeperunderstandingofthemolecularmechanismsunderlyingapomixisinhawthorns,chromosomalgenomicsanalysiswasconducted.Thisanalysisrevealedthattherewerenomajordifferencesinchromosomenumberorstructurebetweenapomicticandsexualplants,suggestingthatapomixisinhawthornsislikelycontrolledbyspecificgenesandregulatorypathways.

Transcriptfactorandsignalingpathwayanalysisidentifiedseveralkeygenesandpathwaysinvolvedintheregulationofapomixisinhawthorns.SomeofthekeygenesidentifiedincludedtranscriptionfactorssuchasL1,meioticgenessuchasREC8,andgenesinvolvedinembryodevelopmentsuchasWOX2.SignalingpathwayssuchashormonesignalingandMAPKsignalingwerealsofoundtobeinvolvedintheregulationofapomixis.

Inconclusion,thefindingsofthisstudyprovidevaluableinsightsintothecharacteristicsofembryonicdevelopmentandthemolecularmechanismsunderlyingapomixisinhawthorns.TheidentificationofkeygenesandsignalingpathwaysinvolvedinapomixisprovidesafoundationforfurtherresearchintotheapplicationofapomixisinhawthornbreedingprogramsMoreover,thestudyhighlightsthepotentialofapomixisinthehawthornbreedingprogram.Apomixiscanbeutilizedtoproduceclonesofsuperiorvarieties,eliminatingtheneedforvegetativepropagation,whichistime-consumingandlabor-intensive.Itcanalsoleadtothecreationofnewcultivarsthroughthegenerationofnewcombinationsofgeneticmaterial.Theexplorationofapomixisinhawthorncanalsohaveasignificantimpactontheconservationofwildpopulations,asitcanprovideanalternativetotraditionalbreedingmethodsthatrequiretheremovalofindividualsfromtheirnaturalhabitats.

Furthermore,theidentificationofkeygenesandsignalingpathwaysinvolvedinapomixisinhawthornscanhavebroaderimplicationsbeyondthedevelopmentofhawthorncultivars.Manyothercrops,suchasmaize,wheat,andcitrus,havebeenreportedtoundergoapomixisorexhibitapomictic-likebehavior.Therefore,theknowledgegainedfromthisstudycanbeappliedtootherplantspecies,providingaframeworkforunderstandingthemolecularmechanismsunderlyingapomixis.

Inconclusion,thestudyofapomixisinhawthornshassignificantimplicationsforbothhawthornbreedingprogramsandthebroaderfieldofplantbiology.TheidentificationofkeygenesandsignalingpathwaysinvolvedinapomixisprovidesafoundationforfurtherresearchintotheapplicationofapomixisinhorticultureandagricultureAdditionally,understandingthemolecularmechanismsofapomixiscanalsoshedlightonevolutionaryprocessesinplants.Apomixishasbeenhypothesizedtoplayasignificantroleinplantspeciationanddiversification,andbystudyingthegenesandpathwaysinvolvedinthisprocess,wecangaininsightintohownewplantspeciesarise.

Moreover,thepotentialapplicationsofapomixisinhorticultureandagriculturearesignificant.Apomixiscouldbeusedtoproducecropsthataretrue-to-type,meaningtheyexhibitthedesiredtraitsandcharacteristicsconsistentlygenerationaftergeneration,withouttheneedfortraditionalbreedingmethods.Thiscouldgreatlyincreasetheefficiencyofcropproductionandreducethetimeandcostassociatedwithtraditionalbreedingprograms.

Furthermore,apomixiscouldalsobeusedinconservationefforts.Byproducinggeneticallyidenticalplantsthroughapomixis,wecanpreserveendangeredplantspeciesandincreasetheirnumberswithoutcompromisingtheirgeneticdiversity.

Overall,thestudyofapomixisinhawthornshasprovidedvaluableinsightsintothisintriguingbiologicalprocess.Ithasnotonlyrevealedthegenesandpathwaysinvolvedinapomixisbutalso