Phylogeny Of Subgen. Synoecia(Ficus,Moraceae) And Species Delimitation Of Ficus Sarmentosa Complex

Due to high species diversity,complex distribution pattern and particular mutualistic relationships with the fig wasps,Ficus has continuously drawn attentions of associated researchers,such as botanists,entomologists and evolutionary biologists.As the cornerstone of these fields,the systematics and taxonomy of Ficus raises great concerns,especially subdivisions for the genus and delimitation of closely related species groups remaining challenging tasks in the study of Ficus.Berg's six subgenera system is the most popular one in subdivision of Ficus,nevertheless,molecular evidences have indicated that there exist some unnatural groups.Displacement of F.pumila and F.laevis makes it is necessary to revise phylogenetic relationship between the subgen.Synoecia and subgen.Ficus.In addition,climbing habit,a key characteristic to establish subgen.Synoecia,also exists in the subgen.Ficus,which derived the rationality of whether climbing habit should be as a trait to divide these subgenera.To assess these problems,about 1/2 species of subgen.Synoecia and2/3 species of subgen.Ficus,together with representative members of other subgenera,total up to 147 species with three nuclear loci,ITS,ETS and G3 pdh,were used to reconstruct phylogenetic trees.These samples cover all the sections and geographical distribution regions of the two subgenera.Ancestral area and life form reconstructions were performed to trace evolutionary history of Ficus.There is F.sarmentosa complex with morphology varying widely in the subgen.Synoecia,which consists of a mass of taxa,involving multiple ranks,such as related species,satellite species and varieties.Abundant sympatric taxa exist in the complex.Phylogenetic relationships and circumscriptions among the complex are still unclear.Therefore,F.sarmentosa complex,as a case to discover biological processes,such as speciation,gene flow and hybridization etc.,was explored here to solve species delimitation issue of the species complex.Considering one-sidedness of species delimitation based on single evidence,the present study utilized integrative taxonomy together with multiple evidences,namely morphology,nuclear loci,chloroplast loci and SSR makers,to discover the species boundaries and evolutionary history of F.sarmentosa complex.Morphologically,35 traits of 80 individuals were analyzed via PCo A,UPGMA and correlation analysis.For DNA analyses,three nuclear makers(ITS,ETS and G3pdh)and four chloroplast makers(psb K-psb I,trn H-psb A,trn L-trn F and trn S-trn G)of 98 samples were used in phylogenetic tree and network reconstructions,and Bayesian species delimitation.For SSR analyses,12 SSR polymorphic loci of 39 populations in total 662 samples were collected,and their population genetic parameters and Bayesian genetic cluster analyses were implemented.At last,results from these multiple evidences were comprehensively analyzed to achieve integrative taxonomy of F.sarmentosa complex.Based on datasets obtained from above systematic and taxonomical analyses,the results are as follows:1.Neither subgen.Synoecia nor subgen.Ficus is a monophyletic group,however,they together constitute a strong-supported monophyly.This monophyly is composed of two well-supported clades,the first one including subsect.Frutescentiae(sect.Ficus)and subsect.Plagiostigma(sect.Pogonotrophe),and the second one including sect.Eriosycea,sect.Apiosycea and the remains of sect.Pogonotrophe.2.Ancestral area reconstruction revealed that the first clade has a distinct origin in East Asia,but it remains unclear in the second clade.Ancestral life form reconstruction suggested that the climbing habit,the key trait to divide subg.Ficus and subg.Synoecia,originated independently more than four times,rendering it unsuitable to circumscribe these subgenera.3.According to phylogeny and ancestral area and life form reconstructions,subgen.Ficus was merged into subgen.Synoecia,and then two sections Apiosycea and Plagiostigma were newly assigned with nine new synonyms.4.Ficus sarmentosa complex is a species group with poorly differentiated morphology and genetic background,and it is in the process of quick speciation along with abundant hybridization,gene flow and incomplete linage sorting.5.The species status of Ficus pumila is recognized.Its two varieties,F.pumila var.pumila and F.pumila var.awkeotsang,are undifferentiated in the genetic background.However,diversities exist in morphology and pollinating ecology.Thus,the status of these two varieties is supposed to be reserved.6.Ficus pubigera var.maliformis and F.pubigera var.pubigera should be raised to the species rank respectively,and F.pubigera var.maliformis should be merged into F.verrucosa.Simultaneously,the status of F.dinganensis has been verified,while unidirectional recent gene flow was detected from F.pubigera(s.l.)to F.dinganensis.7.Two varieties of F.sarmentosa,F.sarmentosa var.thunbergii and F.sarmentosa var.lacrymans,should be raised to the species rank.According to their genetic background and distribution region pattern,it is inferred that their speciation modes are peripatric speciation and budding speciation respectively.8.The remaining taxa in the complex,i.e.Ficus sarmentosa var.duclouxii,F.sarmentosa var.henryi,F.sarmentosa var.impressa,F.sarmentosa var.luducca,F.sarmentosa var.luducca f.sessilis,F.sarmentosa var.nipponica,Ficus sarmentosa var.sarmentosa,F.guangxiensis,F.guizhouensis,F.napoensis and F.polynervis should all be merged into F.sarmentosa.9.On the whole,the eighteen nominal taxa in the complex decreased to seven species and one variety.Taxonomic treatments and a key are implemented.The conclusions make an achievement for new frame of subgenus subdivision in Ficus and a case of integrative taxonomy in the delimitation of the species complex.