Subjects: Biology >> Botany >> Applied botany submitted time 2021-07-20 Cooperative journals: 《广西植物》
Abstract： Phylogenetic analyses supported that four traditionally defined families Sterculiaceae, Tiliaceae, Bombacaece and Malvaceae were subsumed into Malvaceae s.l. and nine subfamilies have been recognized within Malvaceae s.l. However, phylogenetic relationships among the nine subfamilies were not well resolved. Moreover, phylogenetic relationships among genera were also not clear in Sterculioideae. In this study, we reconstructed phylogenetic trees of Malvaceae s.l. based on chloroplast genome sequences from 55 species that representing eight recognized subfamilies for clarifying phylogenetics relationships of subfamilies and Sterculioideae. The results were as follows: (1) Byttnerioideae and Grewioideae formed the Byttneriina clade in Malvaceae s.l. as sister to the Malvadendrina clade which by having Helicteroideae as the first divergent subfamily, followed by Sterculioideae (WCG, LSC and SSC datasets), and the Malvatheca clade (Bombacoideae + Malvoideae) and the clade Dombeyoideae + Tilioideae as sister. (2) The Cola clade was the first divergent clade in Sterculioideae, then the Brachychiton clade was sister to the clade Sterculia + Heritiera (WCG, LSC and CDS datasets); (3) In the Cola clade, Cola + Octolobus + Pterygota were the first divergent group, then Firmiana spp. (including Hildegardia) were sister to the clade Scaphium + Pterocymbium. In this study, plastid phylogenomic analyses have well resolved the phylogenetic framework of subfamilies in Malvaceae s.l., and phylogenetic relationship among genera in Sterculioideae. However, phylogenetic positions of Sterculioideae in the Malvadendrina clade and Brachychiton in Sterculioideae, respectively, as well as the concept and circumscription of Firmiana, need to confirm and further investigate using nuclear genomic data in the future.
Subjects: Biology >> Botany >> Applied botany submitted time 2021-07-20 Cooperative journals: 《广西植物》
Abstract： The Convolvulaceae is a pantropical family with high morphological diversity and economic values. To date, however, the phylogenetic relationships among the major lineages or tribes in the family have not been fully resolved. In order to resolve these relationships, we sampled the complete plastome sequences from 40 species, representing eight recognized tribes of Convolvulaceae, and reconstructed phylogenetic trees by using both Maximum Likelihood and Bayesian Inference approaches. As the main results, we found that: (1) Convolvulaceae plastomes have the typical quadripartite structure, with the genome size ranging from 113 273 bp to 164 112 bp and including 66-79 protein-coding genes. (2) Phylogenomic analyses using five datasets (i.e., WCG, CDS, LSC, IR, and SSC matrixes) show that the topologies of the WCG and CDS trees are identical, with differences in support values for some nodes. Topological differences were found between LSC and WCG topologies, especially for the positions of Cuscuteae, Dichondreae, and Cresseae. The AU and SH tests show that topological conflicts are significant between the WCG tree and the SSC and IR trees. (3) All phylogenetic analyses confirm that Cuscuta and Dichondreae are nested in Convolvuloideae and should be treated as tribes. (4) Phylogenetic relationships among the eight tribes are well resolved using the WCG and CDS datasets: Cardiochlamyeae and Erycibeae form a clade as the first divergent group of Convolvuloideae, followed by Cuscuteae, with the remaining five tribes forming two major clades. (5) The phylogenomic analyses confirm that Merremieae, and in particular the genus Merremia, are polyphyletic, and that the circumscription and taxonomy of both Merremieae and Merremia need revision.
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