Phylogeny and Taxonomy of Eurya (Ternstroemiaceae) from Taiwan, As Inferred from ITS Sequence Data
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Botanical Studies (2007) 48: 97-116. TAXONOMY Phylogeny and taxonomy of Eurya (Ternstroemiaceae) from Taiwan, as inferred from ITS sequence data Chi-ChihWU,Zhi-FuHSU,andChih-HuaTSOU* Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, R.O.C. (ReceivedMay,192006;AcceptedAugust24,2006) ABSTRACT. EuryaisthelargestgenusintheTernstroemiaceae.The13EuryaspeciesinTaiwanconstitute animportantelementinvarioushabitatsfromlowtohighelevatedforestsintheisland.Inanattemptto understandtheinterspeciesrelationshipsandgeographicalhistoryofthese13species,wesequenced123 samplesrepresenting32EuryaspeciesfromTaiwan,theRyukyus,continentalChina,andSoutheastAsia at the nuclear ITS region. Sixteen species of five other genera of Ternstroemiaceae were also incorporated. MolecularphylogenetictreesshowthattheEuryaspeciesstudiedformamonophyleticgroup,organizedinto five clades with geographical correlations. All the 17 EuryaspeciesfromTaiwanandtheRyukyusstudied, exceptE. loquaiana,togetherconstitutetwocoherent,butdistantlyrelatedclades:onecladestandsatabasal and isolated position, with four out of its five species endemic to these two regions; they are probably Tertiary elementsofnorthernChinaortheirdirectdescendants.Theothercladeismuchmoreadvancedandhasstrong affinity to the EuryainsoutheastChina,whichsuggeststhatthememberswereprobablyoriginatedfromthe QuaternaryfloraofsoutheastChina.Ecologicalpartitioningisthoughttobethemajormechanismforthe speciationoffourTaiwan-endemicspeciesfromE. chinensis. Keywords:Eurya;ITS;Ternstroemiaceae;Phylogeny;Taiwan;TheRyukyus. INTRODUCTION theRyukyuslistedinthe“FloraoftheRyukyus,Southof AmamiIsland”(HatusimaandAmano,1994)alsoreveals TaiwanissituatedatthejunctionoftheRyukyuand that96%(650outof672)ofitsnativegeneraarealso theLuzonArcs,andisseparatedfromFujianProvince, nativetoTaiwan. Chinabythe150kmwideTaiwanStrait(Figure1).When theoverallfloraofthisregionbecameexploredinthe early20th century, it became clear that the flora of Taiwan mainlyoriginatedfromcontinentalChina(Wilson,1920; Masamune,1934;Kanehira,1936;Li,1957;Hosokawa, 1958)andtheelementsfromthePhilippineswerelimited andrestrictedtotheverysouth(Merrill,1926;Liand Keng, 1950; Li, 1953); while the flora of the Ryukyus (up totheAmamigroup)wasconsideredasanextensionofthe flora of Taiwan,separated from the flora of Japan (Kyushu Islandandtothenorth)(Masamune,1934;Sonoharaet al.,1952;Hosokawa,1958).Theseearlierviewpointson the floristic affinities have been supported by later floristic analyses(LiuandTeruya,1980;Hsiehetal.,1994;Shen, 1997;Hsieh,2002).Awellacceptedexplanationbased ongeological/geographicalinformationisthattheTaiwan Straitismostlyonly60-80mdeepandservedasabridge connectingcontinentalChinaandTaiwanseveraltimes duringthePleistoceneglacialepisodes,whereastheBashi StraitbetweenTaiwanandLuzonIslandisdeeperthan 2,000mandtheseislandshaveneverbeenconnected (Shen,1996).Ourcomparisononthenativegeneraof *Correspondingauthor:E-mail:[email protected]. Figure 1. MapofSEAsiaandEAsia. 98 Botanical Studies, Vol. 48, 2007 ThesephytogeographicalstudiesofTaiwanwerelarge- MATERIALS AND METHODS scaledanalysesoftheentireflorasorligneousflorasof theseregions.Inrecentyears,adoptingmoleculartools Sampling:Allthe13Euryaspeciesdistributedin inphytogeographicalstudiesontheplantsofTaiwanhas Taiwan, five out of the seven occurring in the Ryukyus, becomeprevalent;however,themajoritywerefocused and12outofthe18occurringinFujian,Chinawere ontheinter-polulationrelationshipswithinasingle collected in the field. (The 12 Fujian species were species,e.g.,Cycas taitungensis(Huangetal.,2001), collectedfromFujian,Guangdong,and/orHongKong). Cyclobalanopsis glauca(Huangetal.,2002);Kandelia Euryaspeciesfromotherareasandfiveothergenera candel(Chiangetal.,2001),Michelia formosana(Lin, inTernstroemioideae,includingAdinandra,Cleyera, 2001;Luetal.,2002),Myrica japonica(Chengetal., andEuryodendronoftribeFreziereaeandAnneslea 2000),Trochodendron aralioides (Wuetal.,2001),and andTernstroemiaoftribeTernstroemieae,werealso Tritanotrichun oldhamii(Wangetal.,2004).Congeneric incorporated(Table1,Appendix1).Leafmaterialswere specieshaverarelybeeninvestigated,e.g.,Gentiana immediatelyputinsilicagelafterdetachmentinthe (Chen,2001).Thegoalofourstudyistoapproachthe field;whilevoucherspecimensweredepositedinthe phylogeographyofagenusfromTaiwanbyanalyzingit herbarialistedinTable1.Sequencingforchloroplast togetherwithcongenericspeciesoccurringintheRyukyus DNAregionspsbA-trnHandtrnL-trnFwascarriedout andFujianProvince,China.ThegenusEuryawaschosen in24and4species,respectively(Appendix2);because forthreereasons.First,wehavebeenworkingona theirrespectivesequencevariationsweretoolowfor revisionofEuryainTaiwanandhaveacquiredanessential interspecies comparison, no more sequencing was speciesconceptofthegenusinthisregion.Second,the continued(detailsprovidedintheResults).Sequencing total19Eurya speciesoccurringintheRyukyusand forthenuclearITS(internaltranscribedspacer)DNA Taiwanexhibitcomplexdistributionpatterns.Fiveare regionwascarriedoutin123samplesof32Euryaspecies endemictotheRyukyus(E. osimensis,E. ryukyuensis, and 23 samples of 14 species from the other five genera E.sakishimensis,E. yaeyamensis,andE. zigzag),eight (Table1).Theratherextensivesamplingwasintended toTaiwan(E. crenatifolia,E. glaberrima,E.hayatai,E. tohaveapreliminarysurveyontheITSintraspecific leptophylla,E. nanjenshanensis,E. rengechinensis,E. variationofEuryaspeciesandtoascertainthesuitability septata,andE. strigillosa).ThreeoccurinbothTaiwan ofinferringITSsequencesinthepresentphylogenetic andSEChina,butnotinJapan/theRyukyus(E. chinensis, study.ThedesignofthesamplingwasthatforeachEurya E. loquaiana,E. nitida).OneispresentinTaiwanand speciesoccurringinTaiwanandtheRyukyusatleast probablyinthePhilippinesaswell(E. gnaphalocarpa) threesamplesshouldbesequenced.Whentwoormore (Ling,1998),oneispresentintheRyukyus(andJapan) con-specificsamplesexhibitedidenticalsequences,no andChina,butnotinTaiwan(E. japonica),andoneoccurs moresequencingforthatspecieswasrequiredandthat inallthreeregions(E. emarginata).Thirdly,theratioof sequencetypewouldbechosentorepresentthespecies endemicEurya speciesishighinTaiwan(8/13=62%)and andregisteredintheGenBank;otherwise,moresamples theRyukyus(5/7=71%);thus,Euryaappearstobeagood should be sequenced until the requirement was fulfilled. subjectforphytogeographicalresearch. Asforthespeciesfromotherregionsandofothergenera, Eurya, comprising c. 130 species (Ling, 1998), theamountofsampleswasnotverymany,thusmostof was the largest of the nine genera in the subfamily the samples were sequenced. The number of con-specific Ternstroemioideae ofTheaceae; but in the recent samplesinthisstudyrangedfromoneto27.Forthose angiospermphylogenysystem,Ternstroemioideaeis Euryaspecieswithwidedistributionranges,multiple removedfromTheaceaeandcombinedwithPentaphyllax con-specific samples were usually chosen from different (Pentaphyllacaceae)toformTernstroemiaceae(Stevens, countries/islands. 2006).ThegenusEuryadistributesfromSEAsia,EAsia, DNA extraction, amplification, and sequencing. tothePacifics,withcontinentalChinaasthecenterof Total DNA was extracted from silica gel-dried or diversity(Ling,1998).ThespeciesofEuryaareoften herbariummaterialfollowingtheprotocolsdescribedin commonorevendominantinvarioushabitatsinTaiwan, Struweetal.(1998). suchasriverbanks,coastalforests,windymountainslops, ITS. Amplificationoftheinternaltranscribedspacer orcoldandhumidforests.Inthisstudy,forthetaxonomic (ITS)regionwhichiscomposedofITS1,the5.8gene,and treatmentofEurya,wefollowedtheManualofTaiwan ITS2wasdonebyusingprimersITSleu1(Urbatschetal., VascularPlants(Liuetal.,1998)forthespeciesin 2000)andITS4(Whiteetal.,1990).ThePCRprogram Taiwan,withtheadditionofonenewspecies,E. septata wassetas94°Cfor5minfollowedby35cyclesof94°C (Wuetal.,2003).ForEuryaintheRyukyus,besidesthe for1min,56°Cfor1min,72°C1min,andasinglecycle sixspeciesrecognizedintheFloraofOkinawaandthe of72°Cfor7min.SequencingwasdonebyusingITSleu1 SouthernRyukyuIslands(Walker,1976)andtheCheck andITS4primers. ListVascularFlorasofRyukyusIslands(Shimabaku, trnL-trnF. AmplificationofthetrnL-trnFwhich 1997),wealsoacceptedE. ryukyuensisasanindependent iscomposedoftrnLintron,trnL3’geneandtrnL-trnF species.ForEuryaincontinentalChina,theFloraof intergenicspacerwasdonebyusingprimersTabCand China(Ling,1998)wasfollowed. WU et al. — Phylogeny and taxonomy of andtaxonomy —Phylogeny WU etal. Table 1. ListofITSsequencingsamples.Thetotal146samplesinclude123of32Eurya species and 23 of 14 species of other five genera of Ternstroemiaceae. The registered accession number and sequence variation among the con-specific samples are provided. Vouchers are deposited at HAST (Herbarium of Academia Sinica, Taiwan, ROC). Three sequences obtainedfromGenBankarelistedasfootnotes. Con-speciessampleswithidenticalITS GenBank Sampleswith1,2,or3sitesdifferent No.of Speciesname Distributionrange sequence.Thesequenceandonevoucher(the accession fromtheregisteredsequenceafter samples onewith*)areregisteredintheGenbank number alignment Eurya acuminata DC.var.acuminata SChina,SEAsia 1 Tsou 1538* AY626852 Eurya acuminatavar.wallichiana Dyer Thailand 1 Maxwell 2004-233* AY626883 Eurya acuminatissima Merr.&Chun C&SChina 2 Tsou et al. 1813*, 1814 AY626853 Eurya amplexifolia Dunn SChina(incl.Fujian) 1 Tsou 1578* AY626854 Eurya chinensis R.Br.var.chinensis(E. Taiwan,SEChina(Fujian) 10 Tsou et al. 1250, 1327, 1330*, 1378, 1379, AY626855 1site:Tsou et al. 1269 Eurya chinensis-T) 1423, 1425 2sites:Tsou et al. 1258, 1720 Eurya chinensis R.Br.var.chinensis(E.