Molecular Phylogenetics Of Some Iris Species In China Based On ITS And MatK Markers

Iris L.is the largest genus in Iris family.Its unique flower shape,rich colors,and evergreen leaves,have a very high ornamental value and broad application prospects.However,genus Iris L.is rich in phenotypic traits,and it is difficult to identify these species which resulting in some controversies in the genus.China is one of the distribution centers of the genus Iris,with about 60 species,and there are most species in the southwest.In this study,we collected 27 species of Iris and 3 outgroup species which were markered using ITS and matK genes.We also downloaded ITS sequences of 4 Iris and matK sequences of 42 Iris(including variations)from Gen Bank.Then based on the ITS and matK gene constructed the Neighbor-Joining tree and Maximum Likelihood tree respectively.The results of the research are as follows:(1)The result of subgenera in genus Iris,we found that in addition to Subgenus Xyridion Spach,the rest of the subgenera were basically consistent with classification of Y.T.Zhao.I.halophila and I.halophila var.Sogdiana,which belong to Subgen.Xyridion,were falled within Subgen.Limniris.So we recommended these two species should be moved to the subgen.Limniris and eliminate the taxonomic status of the subgen.Xyridion.Subgen.Limniris is not a monophyletic group,and the genetic relationship within the genus is more complex.Subgen.Crossiris is an unnatural group,I.proantha var.valida,I.speculatrix and I.latistyla were gathered in other subgenera respectively.Subgen.Iris needs further subdivision;Subgen.Nepalensis is a relatively natural taxonomic group.The taxonomic status of Subgen.Pardanthopsis is reasonable.B.chinensis has been repeatedly assigned to the genus Iris,indicated it closely related to the genus Iris.we suggested that B.chinensis should be included in Subgen.Pardanthopsis.(2)Combing the results of previous studies,the disputed species are treated as follows:the phylogenetic trees indicated that I.lactea var.chinensis and I.lactea var.chrysantha as variations of I.lactea were reasonable;I.ruthenica and I.uniflora were treated as independent species and I.ruthenica var.nana should as a synonym of I.ruthenica;I.japonica,I.confusa,and I.wattii were treated as independent species;we supported I.goniocarpa var.grossa was elevated to species level.I.goniocarpa var.tenella is treated as a synonym of I.goniocarpa,I.subdichotoma should be assigned to Subgen.Nepalensis because it embed within this subgenus,and I.collettii var.acaulis should be elevated to species level;I.sichuanensis and I.leptophylla were closely related to each other,however there are some subtle difference in their phenotypic character so they should be treated as independent species;I.pandurate and I.tigridia clustered far from each other,we suggested that they should be treated as independent species.We also found that I.speculatrix and I.proantha var.valida were more related to Subgen.Limniris in the phylogenetic trees,however their outer tepals with crest which are same with Subgen.Crossiris,so we considered that they might be transitional species between the two subgenera;I.latistyla was closely related to Subgen.Nepalensis,but its specific status requires more data to be discussed later.