Limits...
Taxonomic position and phylogeny of the genus Vargasiella (Orchidaceae, Vandoideae) based on molecular and morphological evidence.

Szlachetko DL, Górniak M, Kolanowska M, Mytnik-Ejsmont J, Kowalkowska AK, Rutkowski P, Koliński T - PLoS ONE (2014)

Bottom Line: The outcomes from the morphological studies indicated significant differences between Vargasiella, Warrea and Warreopsis.Vargasiella seems to be an outshoot of the main branch of evolution of the Zygopetaleae.The molecular analysis and morphological data suggest that Vargasiella and Warrea could have evolved from a common ancestor.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Taxonomy and Nature Conservation, The University of Gdańsk, Gdańsk, Poland.

ABSTRACT
Since the description of the Neotropical genus Vargasiella in 1952, its taxonomic position has remained unclear, mainly due to a lack of sufficient data. In this study, the taxonomic position of Vargasiella was revised based on the outcomes of macro- and micromorphological studies, analyses of selected molecular markers and ecological methods of niche distribution modeling. The phylogenetic relationships were inferred using three DNA markers: matK, trnL-F and ITS sequences. The morphological studies included the analysis of macromorphological features of herbarium specimens as well as micromorphological examination of preserved flowers. The ecological niche modeling was applied to identify the distribution of the suitable niches of the studied taxa. The relationships between Vargasiella and most similar taxa remain unresolved based on the molecular analysis. The outcomes from the morphological studies indicated significant differences between Vargasiella, Warrea and Warreopsis. Moreover, a niche shift in response to changing climate after the last glacial maximum is observed in Vargasiella, while no substantial changes in the occupied habitats were identified in the other related taxa. The clocktree of the Zygopetaleae estimated from the matK gene indicated that the most recent common ancestors of Vargasiella, Warrea and Warreopsis originated in the Miocene, while the divergence time for Vargasiella and Warrea was assessed at approximately 5.4 Ma ago. Vargasiella seems to be an outshoot of the main branch of evolution of the Zygopetaleae. It is noteworthy that the Vargasiella-Warrea dichotomy could have taken place later than the divergence of Warreopsis from the mutual lineage. The molecular analysis and morphological data suggest that Vargasiella and Warrea could have evolved from a common ancestor. Accumulation of morphological differences and acceleration of the evolution of Vargasiella were more intensive than in other Warreinae and this could probably be synchronized with adaptation to different climatic conditions.

Show MeSH

Related in: MedlinePlus

One of the most parsimonious trees in the ITS, matK and trnL-F analyses for Zygopetalinae Schltr.The Vargasiella peruviana C.Schweinf. is highlighted in bold. The numbers above branches are Fitch branch lengths. Bootstrap percentages >50 are given for supported clades below branches. Arrows indicate clades that collapse in the strict consensus tree.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4043880&req=5

pone-0098472-g003: One of the most parsimonious trees in the ITS, matK and trnL-F analyses for Zygopetalinae Schltr.The Vargasiella peruviana C.Schweinf. is highlighted in bold. The numbers above branches are Fitch branch lengths. Bootstrap percentages >50 are given for supported clades below branches. Arrows indicate clades that collapse in the strict consensus tree.

Mentions: The result of the individual and combined analyses are presented in one of the most parsimonious trees. Bootstrap support (BS) above 50% is given for supported clades below branches. Branches that collapse in the strict consensus tree are indicated by arrows. Statistics for one of the most parsimonious trees from each analysis is shown in the Table 1. Statistics for matK, trnL-F, ITS and combined data matrices are separated by “/”. The number of analysed taxa were 85/82/85/85 respectively. The aligned matrix comprised 1327/1389/842/3558 characters of which 233/286/374/1392 were variable and 134/132/263/529 were potentially parsimony informative. The number of the most parsimonious trees were 48/416/3258/10.000. Tree-length was 374/995/818/1640, consistency index (CI) = 0.72/0.77/0.77/0.68, and retention index (RI) = 0.83/0.86/0.86/84. Results from the partition homogeneity test indicate incongruence between all (plastid and nuclear partitions): matK/trnL-F P = 0.01; matK/ITS P = 0.01; trnL-F/ITS P = 0.01; matK/trnL-F/ITS P = 0.01. A visual comparison of the topology and bootstrap support between plastid and ITS data sets shows incongruence between low supported clades. In this case combined analyses were performed. On a combined ITS-matK-trnL-F tree (Fig. 3), the analysed genera are arranged in groups congruent with Szlachetko's subtribes [8], i.e. Huntleyinae Schltr. (pseudobulbs lacking or obscure), Zygopetalinae s.str. (heteroblastic pseudobulbs) and Warreinae Szlach. (homoblastic pseudobulbs). Dichaeinae (monopodial plants) and Cryptarrheninae Dressl. (pseudobulbs obscure or absent) are nested in this clade as well. In all analyses, Vargasiella composes a highly supported subclade together with Warrea and Warreopsis (ITS 97 BS; matK 95 BS; trnL-F 80 BS (only Warrea-Vargasiella); combined 100 BS). The subclade is situated at the base of the Zygopetalinae sensu lato clade and it is sister to the rest of the taxa (except for the matK tree where it forms a basal polytomy with the other subclades). The relationships between Warrea, Warreopsis and Vargasiella are not resolved. In all strict consensus trees (not shown) the Warrea-Vargasiella clade present in the matK and combined trees is collapsed.


Taxonomic position and phylogeny of the genus Vargasiella (Orchidaceae, Vandoideae) based on molecular and morphological evidence.

Szlachetko DL, Górniak M, Kolanowska M, Mytnik-Ejsmont J, Kowalkowska AK, Rutkowski P, Koliński T - PLoS ONE (2014)

One of the most parsimonious trees in the ITS, matK and trnL-F analyses for Zygopetalinae Schltr.The Vargasiella peruviana C.Schweinf. is highlighted in bold. The numbers above branches are Fitch branch lengths. Bootstrap percentages >50 are given for supported clades below branches. Arrows indicate clades that collapse in the strict consensus tree.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4043880&req=5

pone-0098472-g003: One of the most parsimonious trees in the ITS, matK and trnL-F analyses for Zygopetalinae Schltr.The Vargasiella peruviana C.Schweinf. is highlighted in bold. The numbers above branches are Fitch branch lengths. Bootstrap percentages >50 are given for supported clades below branches. Arrows indicate clades that collapse in the strict consensus tree.
Mentions: The result of the individual and combined analyses are presented in one of the most parsimonious trees. Bootstrap support (BS) above 50% is given for supported clades below branches. Branches that collapse in the strict consensus tree are indicated by arrows. Statistics for one of the most parsimonious trees from each analysis is shown in the Table 1. Statistics for matK, trnL-F, ITS and combined data matrices are separated by “/”. The number of analysed taxa were 85/82/85/85 respectively. The aligned matrix comprised 1327/1389/842/3558 characters of which 233/286/374/1392 were variable and 134/132/263/529 were potentially parsimony informative. The number of the most parsimonious trees were 48/416/3258/10.000. Tree-length was 374/995/818/1640, consistency index (CI) = 0.72/0.77/0.77/0.68, and retention index (RI) = 0.83/0.86/0.86/84. Results from the partition homogeneity test indicate incongruence between all (plastid and nuclear partitions): matK/trnL-F P = 0.01; matK/ITS P = 0.01; trnL-F/ITS P = 0.01; matK/trnL-F/ITS P = 0.01. A visual comparison of the topology and bootstrap support between plastid and ITS data sets shows incongruence between low supported clades. In this case combined analyses were performed. On a combined ITS-matK-trnL-F tree (Fig. 3), the analysed genera are arranged in groups congruent with Szlachetko's subtribes [8], i.e. Huntleyinae Schltr. (pseudobulbs lacking or obscure), Zygopetalinae s.str. (heteroblastic pseudobulbs) and Warreinae Szlach. (homoblastic pseudobulbs). Dichaeinae (monopodial plants) and Cryptarrheninae Dressl. (pseudobulbs obscure or absent) are nested in this clade as well. In all analyses, Vargasiella composes a highly supported subclade together with Warrea and Warreopsis (ITS 97 BS; matK 95 BS; trnL-F 80 BS (only Warrea-Vargasiella); combined 100 BS). The subclade is situated at the base of the Zygopetalinae sensu lato clade and it is sister to the rest of the taxa (except for the matK tree where it forms a basal polytomy with the other subclades). The relationships between Warrea, Warreopsis and Vargasiella are not resolved. In all strict consensus trees (not shown) the Warrea-Vargasiella clade present in the matK and combined trees is collapsed.

Bottom Line: The outcomes from the morphological studies indicated significant differences between Vargasiella, Warrea and Warreopsis.Vargasiella seems to be an outshoot of the main branch of evolution of the Zygopetaleae.The molecular analysis and morphological data suggest that Vargasiella and Warrea could have evolved from a common ancestor.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Taxonomy and Nature Conservation, The University of Gdańsk, Gdańsk, Poland.

ABSTRACT
Since the description of the Neotropical genus Vargasiella in 1952, its taxonomic position has remained unclear, mainly due to a lack of sufficient data. In this study, the taxonomic position of Vargasiella was revised based on the outcomes of macro- and micromorphological studies, analyses of selected molecular markers and ecological methods of niche distribution modeling. The phylogenetic relationships were inferred using three DNA markers: matK, trnL-F and ITS sequences. The morphological studies included the analysis of macromorphological features of herbarium specimens as well as micromorphological examination of preserved flowers. The ecological niche modeling was applied to identify the distribution of the suitable niches of the studied taxa. The relationships between Vargasiella and most similar taxa remain unresolved based on the molecular analysis. The outcomes from the morphological studies indicated significant differences between Vargasiella, Warrea and Warreopsis. Moreover, a niche shift in response to changing climate after the last glacial maximum is observed in Vargasiella, while no substantial changes in the occupied habitats were identified in the other related taxa. The clocktree of the Zygopetaleae estimated from the matK gene indicated that the most recent common ancestors of Vargasiella, Warrea and Warreopsis originated in the Miocene, while the divergence time for Vargasiella and Warrea was assessed at approximately 5.4 Ma ago. Vargasiella seems to be an outshoot of the main branch of evolution of the Zygopetaleae. It is noteworthy that the Vargasiella-Warrea dichotomy could have taken place later than the divergence of Warreopsis from the mutual lineage. The molecular analysis and morphological data suggest that Vargasiella and Warrea could have evolved from a common ancestor. Accumulation of morphological differences and acceleration of the evolution of Vargasiella were more intensive than in other Warreinae and this could probably be synchronized with adaptation to different climatic conditions.

Show MeSH
Related in: MedlinePlus