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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.

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Vargasiella venezuelana C.Schweinf.(A) Lip with central fleshy disc divided into two thickenings. (B) Lip base. (C) Details of (B): the irregularly sized rounded cells to obpyriform and conical papillae, visible cuticle swellings on the cells. (D) Lip middle part and apex. (E) Detail of (D). Surface between thickenings built by the obpyriform to slightly conical papillae (F). (G) Conical papillae present on the thickenings; Visible cuticle swellings on the cells (F-G). (H) The involute undulate margins built by groups of elongated conical papillae. (I) Papillae (detail of H) covered by undulated cuticle, cuticle swellings also present.
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pone-0098472-g006: Vargasiella venezuelana C.Schweinf.(A) Lip with central fleshy disc divided into two thickenings. (B) Lip base. (C) Details of (B): the irregularly sized rounded cells to obpyriform and conical papillae, visible cuticle swellings on the cells. (D) Lip middle part and apex. (E) Detail of (D). Surface between thickenings built by the obpyriform to slightly conical papillae (F). (G) Conical papillae present on the thickenings; Visible cuticle swellings on the cells (F-G). (H) The involute undulate margins built by groups of elongated conical papillae. (I) Papillae (detail of H) covered by undulated cuticle, cuticle swellings also present.

Mentions: The characteristic feature of the lip of Vargasiella peruviana is the presence of the central fleshy disc which is divided into two calli (Fig. 6A) starting from the base (Fig. 6A-B, D). The epidermis of the lip base is built by irregularly sized rounded cells to obpyriform and conical papillae (Fig. 6C). Between the thickenings (Fig. 6D-E), obpyriform to slightly conical papillae are noticed (Fig. 6E-F). The bigger conical papillae are distinctly visible on the calli (Fig. 6G). The cuticle swellings are noticed on the whole inner lip surface (Fig. 6C, F, G, I). The involute an undulate margins (Fig. 6H) consist of groups of elongated conical papillae, covered by undulated cuticle (Fig. 6I). The stout, short gynostemium with a large, deltoid, deeply concave stigma (Fig. 7A-C) is covered by flat cells with a regularly ridged cuticle (Fig. 7E-G) or conical papillae (Fig. 7D-F). The rounded to conical papillae occurring on the edge of the clinandrium (Fig. 7C-D) are covered by a cuticle with thick ridges. Under the stigma, close to the column margins, a few longer papillae are noticed (Fig. 6E) with visible drops of secretory remnants on their surface (Fig. 7F). The paracytic type of stomata is present (Fig. 7G). The four obovoid-ellipsoid pollinia are grouped in two pairs (Fig. 7H).


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)

Vargasiella venezuelana C.Schweinf.(A) Lip with central fleshy disc divided into two thickenings. (B) Lip base. (C) Details of (B): the irregularly sized rounded cells to obpyriform and conical papillae, visible cuticle swellings on the cells. (D) Lip middle part and apex. (E) Detail of (D). Surface between thickenings built by the obpyriform to slightly conical papillae (F). (G) Conical papillae present on the thickenings; Visible cuticle swellings on the cells (F-G). (H) The involute undulate margins built by groups of elongated conical papillae. (I) Papillae (detail of H) covered by undulated cuticle, cuticle swellings also present.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0098472-g006: Vargasiella venezuelana C.Schweinf.(A) Lip with central fleshy disc divided into two thickenings. (B) Lip base. (C) Details of (B): the irregularly sized rounded cells to obpyriform and conical papillae, visible cuticle swellings on the cells. (D) Lip middle part and apex. (E) Detail of (D). Surface between thickenings built by the obpyriform to slightly conical papillae (F). (G) Conical papillae present on the thickenings; Visible cuticle swellings on the cells (F-G). (H) The involute undulate margins built by groups of elongated conical papillae. (I) Papillae (detail of H) covered by undulated cuticle, cuticle swellings also present.
Mentions: The characteristic feature of the lip of Vargasiella peruviana is the presence of the central fleshy disc which is divided into two calli (Fig. 6A) starting from the base (Fig. 6A-B, D). The epidermis of the lip base is built by irregularly sized rounded cells to obpyriform and conical papillae (Fig. 6C). Between the thickenings (Fig. 6D-E), obpyriform to slightly conical papillae are noticed (Fig. 6E-F). The bigger conical papillae are distinctly visible on the calli (Fig. 6G). The cuticle swellings are noticed on the whole inner lip surface (Fig. 6C, F, G, I). The involute an undulate margins (Fig. 6H) consist of groups of elongated conical papillae, covered by undulated cuticle (Fig. 6I). The stout, short gynostemium with a large, deltoid, deeply concave stigma (Fig. 7A-C) is covered by flat cells with a regularly ridged cuticle (Fig. 7E-G) or conical papillae (Fig. 7D-F). The rounded to conical papillae occurring on the edge of the clinandrium (Fig. 7C-D) are covered by a cuticle with thick ridges. Under the stigma, close to the column margins, a few longer papillae are noticed (Fig. 6E) with visible drops of secretory remnants on their surface (Fig. 7F). The paracytic type of stomata is present (Fig. 7G). The four obovoid-ellipsoid pollinia are grouped in two pairs (Fig. 7H).

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