茶树变异的分子机理研究正文.docx
《茶树变异的分子机理研究正文.docx》由会员分享,可在线阅读,更多相关《茶树变异的分子机理研究正文.docx(41页珍藏版)》请在冰豆网上搜索。
![茶树变异的分子机理研究正文.docx](https://file1.bdocx.com/fileroot1/2022-10/25/b6c8767c-f6d1-4f18-966d-739b1dcf377d/b6c8767c-f6d1-4f18-966d-739b1dcf377d1.gif)
茶树变异的分子机理研究正文
摘要
茶树(Camelliasinensis(L.)O.Ktze.)是一种世界广泛种植且具有经济效益的叶用作物。
因为具有特定叶色的茶叶的特征化学成分与茶叶质量密切相关,因而茶树叶色多样性的研究一直以来被茶业界广为关注。
本研究以黄山群体中花白茶树单株为研究材料,发现花白茶树不同于温敏型白化茶树和光敏型白化茶树随着温度和光照强度变化而变化,经过修剪发现花白性状依然存在。
于是展开花白茶树中内含成分、组织结构、基因表达差异和蛋白表达差异等研究,取得以下研究结果:
(1)通过内含物质的含量比较分析发现,相对于正常叶片,花白叶片的叶绿素含量显著降低,咖啡碱含量略有增长;相较于正常叶片,花白叶片中总儿茶素含量减少了52.66%,而总游离氨基酸含量增加了52.15%,其中花白叶片的茶氨酸含量增长了62.73%。
通过石蜡切片发现花白叶片栅栏组织细胞排列疏松,组织结构的疏松程度显著低于正常叶片,并且观察花白叶片的叶绿体超微结构发现花白叶片的叶绿体发育异常,没有明显的类囊体且存在空腔。
(2)通过对花白叶片与正常叶片转录组学分析,共获得3431个差异表达基因。
针对茶树特征性代谢中茶氨酸和多酚生物合成相关基因进行分析,发现花白叶片在儿茶素代谢途径中的相关基因低于正常叶片,而在茶氨酸代谢途径中的基因趋势相反。
通过分析还发现,花白叶片中叶绿素生物合成代谢途径、光合作用、叶绿体发育和生物合成中差异基因的表达模式受到影响。
花白叶片中光合作用的光捕获天线蛋白基因(LHC)表达均显著低于正常叶片,合成叶绿素途径相关的差异基因表达也低于正常。
(3)通过对花白茶树中花白叶片和正常叶片的蛋白组分析,一共获得95个差异蛋白。
经过KEGG富集分析,结果发现花白茶树在氧化磷酸化,类黄酮生物途径和苯丙素生物合成等重要通路发生了显著变化,同时在光合作用、嘌呤代谢等代谢途径受到影响。
(4)我们在对差异基因进行筛选时发现了Clp蛋白酶复合体与叶绿体发育、植物叶色有关。
以花白叶片和正常叶片为模板,分别扩增CsClpP5基因。
经序列分析发现,从花白叶片中克隆的CsClpP5基因,全长序列为909bp,编码303个氨基酸。
然而正常叶片中扩增的CsClpP5基因全长903bp,编码301个氨基酸。
经过序列比对发现了两个氨基酸位点的突变,而经过磷酸位点的分析发现该突变位点的改变了ClpP5的磷酸位点。
由此我们推测CsClpP5突变,可能与茶树产生花白表型有关。
关键词:
茶树;白化;转录组;蛋白组;CsClpP5基因
Abstract
Asaleafyplant,teaplant(Camelliasinensis(l.)o.Ktze.)isanimportanteconomiccropinChina.Becausethecharacteristicchemicalcompositionofteawithspecificleafcoloriscloselyrelatedtothequalityoftea,thestudyonthecolordiversityoftealeaveshasbeenwidelyconcernedbytheteaindustry.Inthisstudy,singleplantofwhiteteatreeinHuangshanpopulationwasusedastheresearchmaterial,anditwasfoundthatthewhiteteatreewasdifferentfromthetemperature-sensitivealbinoteatreeandlight-sensitivealbinoteatree,whichchangedwiththechangeoftemperatureandlightintensity.Therefore,studieswerecarriedoutonthecomponents,tissuestructure,geneexpressiondifferencesandproteinexpressiondifferencesinthewhiteteaplant,andthefollowingresultswereobtained:
(1)Itwasfoundthroughthecomparativeanalysisofthecontentsofthecontainedsubstancesthatcomparedwiththenormalleaves,thechlorophyllcontentofthewhiteleavesdecreasedsignificantly,andthecaffeinecontentincreasedslightly.Comparedwithnormalleaves,thetotalcatechincontentinthewhiteleavesdecreasedby52.66%,whilethetotalfreeaminoacidcontentincreasedby52.15%,inwhichthetheaninecontentinthewhiteleavesincreasedby62.73%.Throughparaffinsection,itwasfoundthatpalisadetissuecellsofthepallidleaveswerearrangedloosely,andthedegreeoftissuestructurewassignificantlylowerthanthatofthenormalleaves.Theultrastructuralanalysisofthepallidleavesrevealedthatthechloroplastsofthepallidleaveswereabnormallydeveloped,withnoobviousthylakoidsandcavities.
(2)Throughtranscriptomeanalysisofwhiteandnormalleaves,atotalof3431differentialgeneswereobtained.Basedontheanalysisofthegenesrelatedtotheanineandpolyphenolsbiosynthesisinthecharacteristicmetabolismofteatree,itwasfoundthatthegenesrelatedtocatechinmetabolismpathwayinthewhiteleaveswerelowerthanthoseinthenormalleaves,whilethegenesrelatedtotheaninemetabolismpathwaywereopposite.Theanalysisalsoshowedthattheexpressionpatternsofdifferentgenesinchlorophyllbiosynthesisordegradation,photosynthesis,chloroplastdevelopmentandbiosynthesiswereaffected.Theexpressionoflightcaptureantennaprotein(LHC)inphotosyntheticleaveswassignificantlylowerthanthatinnormalleaves,andtheexpressionofdifferentgenesrelatedtothesynthesisofchlorophyllpathwaywasalsolowerthanthatinnormalleaves.
(3)Atotalof95differentiallyexpressedproteinswereobtainedbyproteomicanalysisofthewhiteandnormalleavesofthewhiteteaplant.ThroughKEGGpathwayenrichmentanalysis,theresultsshowedthattheOxidativephosphorylation(Oxidativephosphorylation),flavonoidsbiologicalpathways(Flavonoidbiosynthesis)andstyreneacrylicbiosynthesis(Phenylpropanoidbiosynthesis)andotherimportantpathwayschangeddramatically,butinphotosynthesis,purinemetabolismandothermetabolicpathwayisaffected.
(4)Clpproteasecomplexwasfoundtoberelatedtochloroplastdevelopmentandleafcolorinthescreeningofdifferentialgenes.TheCsClpP5genewasamplifiedinwhiteandnormalleaves.SequenceanalysisshowedthattheCsClpP5geneclonedfromthewhiteleaveswas909bplongandencoded303aminoacids.However,theCsClpP5geneamplifiedinthenormalleaveswasfulllength903bp,encoding301aminoacids.Mutationoftwoaminoacidsiteswasfoundbysequencealignment,andanalysisofthephosphoricacidsiterevealedthatthemutationsitechangedthephosphoricacidsiteofClpP5.Therefore,wespeculatedthatthemutationofCsClpP5mightberelatedtotheproductionofwhitephenotypeinteatrees.
Keywords:
Camelliasinensis;albinophenotype;RNA-seq;Proteomics;CsClpP5gene
1文献综述
1.1白化茶树的研究进展