Marcin Górniak

Phylogenetic relationships within Orchidaceae based on a low-copy nuclear coding gene, Xdh: congruence with organellar and nuclear ribosomal DNA results.

Using parsimony and Bayesian analyses, we estimated higher-level relationships within Orchidaceae, focusing on subfamilies and tribes. DNA sequences of part of the low-copy nuclear protein gene Xdh were obtained for 154 taxa including 126 genera of Orchidaceae and outgroup families of Asparagales. The general topology of the Xdh trees is congruent with those published previously based on plastid protein-coding genes and non-coding nuclear ribosomal DNA. The five subfamilies previously recognized are monophyletic and well supported. The results indicate that monandrous condition evolved independently in Vanilloideae and Epidendroideae/Orchidoideae. The analysis clarifies relationships between tribes of Epidendroideae such as Vandeae sensu lato to Collabieae, Epidendreae to Calypsoeae and Malaxideae to Dendrobieae. Also relationships of Bromheadia, Imerinaea, Sirhookera, and achlorophyllous species of Corallorhiza, Gastrodia, Limodorum, Neottia, Wullschlaegelia are for the first time evaluated in a broad molecular phylogenetic framework.

Taxonomic placement of Paphiopedilum canhii (Cypripedioideae; Orchidaceae) based on cytological, molecular and micromorphological evidence.

Paphiopedilum canhii was discovered in Northern Vietnam. Since its description in 2010, it has caused a stir among taxonomists due to its interesting mixture of morphological features, i.e. marbled, relatively thick leaves, flowers similar to species classified in the section Barbata, and unique, large staminodial shield. On the basis of these features, it is difficult to classify the species to existing infrageneric units. Using cytological data, phylogenetic analyses based on plastid and nuclear genes and the study of the adaxial epidermis of the leaves and gynostemium structure obtained from Scanning Electron Microscopy (SEM) and Light Microscopy (LM), the taxonomic position of P. canhii was determined. These results suggest that P. canhii forms an independent phylogenetic line within the genus Paphiopedilum deserving subgeneric status, already proposed by Braem and Gruss (2011) as Megastaminodium.

Phylogenetic Placement and Taxonomy of the Genus Hederorkis (Orchidaceae)

Three plastid regions, matK, rpl32-trnL and rpl16 intron and the ITS1-5.8S-ITS2 nuclear ribosomal DNA were used to demonstrate a phylogenetic placement of the genus Hederorkis (Orchidaceae) for the first time. The taxonomic position of this genus has been unclear thus far. The phylogenetic and morphological relations of Hederorkis to the most closely related genera Sirhookera, Adrorhizon, Bromheadia and Polystachya are also discussed. A hypothesis concerning an origin and evolution of Hederorkis is proposed. Hederorkis is an epiphytic two-leaved orchid genus with lateral inflorescence, non-resupinate flowers, elongate gynostemium and rudimentary column foot. It is native to the Indian Ocean Islands. Two species of Hederorkis are recognized worldwide, H. scandens endemic to Mauritius and Réunion and H. seychellensis endemic to Seychelles. For each of the species treated a full synonymy, detailed description and illustration are included. The distribution map and dichotomous keys to the species have also been provided.

Taxonomic Position and Phylogeny of the Genus Vargasiella (Orchidaceae, Vandoideae) Based on Molecular and Morphological Evidence

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.

Establishing the cell biology of apomictic reproduction in diploid Boechera stricta (Brassicaceae)

Abstract Background and aims In the Brassicaceae family, apomictic development is characteristic of the genus Boechera. Hybridization, polyploidy and environmental adaptation that arose during the evolution of Boechera may serve as (epi)genetic regulators of apomictic initiation in this genus. Here we focus on Boechera stricta, a predominantly diploid species that reproduces sexually. However, apomictic development in this species has been reported in several studies, indicating non-obligate sexuality. Methods A progressive investigation of flower development was conducted using three accessions to assess the reproductive system of B. stricta. We employed molecular and cyto-embryological identification using histochemistry, transmission electron microscopy and Nomarski and epifluorescence microscopy. Key Results Data from internal transcribed spacer (ITS) and chloroplast haplotype sequencing, in addition to microsatellite variation, confirmed the B. stricta genotype for all lines. Embryological data indicated irregularities in sexual reproduction manifested by heterochronic ovule development, longevity of meiocyte and dyad stages, diverse callose accumulation during meiocyte-to-gametophyte development, and the formation of triads and tetrads in several patterns. The arabinogalactan-related sugar epitope recognized by JIM13 immunolocalized to one or more megaspores. Furthermore, pollen sterility and a high frequency of seed abortion appeared to accompany reproduction of the accession ES512, along with the initiation of parthenogenesis. Data from flow cytometric screening revealed both sexual and apomictic seed formation. Conclusion These results imply that B. stricta is a species with an underlying ability to initiate apomixis, at least with respect to the lines examined here. The existence of apomixis in an otherwise diploid sexual B. stricta may provide the genomic building blocks for establishing highly penetrant apomictic diploids and hybrid relatives. Our findings demonstrate that apomixis per se is a variable trait upon which natural selection could act.

Taxonomy of Cyrtochilum-alliance (Orchidaceae) in the light of molecular and morphological data

BackgroundThe generic separateness and specific composition of the orchid genus Cyrtochilum was discussed for almost two centuries. Over the years several smaller taxa were segregated from this taxon, but their separateness was recently questioned based on molecular studies outcomes. The aim of our study was to revise concepts of morphological-based generic delimitation in Cyrtochilum-alliance and to compare it with the results of genetic analysis. We used phylogenetic framework in combination with phenetical analysis to provide proposal of the generic delimitation within Cyrtochilum-alliance. Two molecular markers, ITS and matK were used to construct phylogenetic tree. A total of over 5000 herbarium specimens were included in the morphological examination and the phenetical analysis included 29 generative and vegetative characters.ResultsComparative morphology of the previously recognized genera: Buesiella, Dasyglossum, Neodryas, Rusbyella, Siederella and Trigonochilum is presented. A new species within the the latter genus is described. Fourteen new combinations are proposed. The key to the identification of the genera of the Cyrtochilum-alliance and morphological characteristics of each genus are provided.ConclusionsA total of six separated genera are recognized within Cyrtochilum-alliance. The reasons of the incompatibility between morphological differences observed within studied taxa and phylogenetic tree are argued and the taxonomic implications of such inconsistency, resulting in fragmentation or lumping of taxonomic units, are discussed.

A phylogenetic and morphological study of Polystachya sect. Superpositae (Orchidaceae) with description of a new species from Cameroon

Polystachya section Superpositae is a group of montane and submontane African epiphytes with thirteen species (including the newly described in this paper). During a scientific expedition to Bamenda Highland, Cameroon a new species, Polystachya bamendae, was found and it is described here. The new entity was compared with 398 herbarium specimens representing the section, including the type collections. The molecular analyses of the ITS and matK strongly support the results of morphological studies and reveal close relationship between the new species and the species of the section Superpositae. Two hypotheses supporting function of the matK gene in the examined species are presented. The phylogenetic and morphological relation of Polystachya bamendae to P. lindblomii and P. superposita is discussed. The distribution range of the section is analyzed and a discussion about the distribution of the species is presented. A distribution map of the section and dichotomous key to the species of Superpositae are provided. The occurrence of the species of the section in two Biodiversity Hotspots (Guinea Forests of West Africa and Eastern Afromontane) is discussed.

Chelystachya, a new genus of the subtribe Polystachyinae (Orchidaceae)

Chelystachya, a new genus of the subtribe Polystachyinae (Orchidaceae) A new genus of Orchidaceae (Polystachyinae), Chelystachya Mytnik & Szlach. is described and illustrated basing on results of molecular and morphological studies. It is related to Polystachya Hook. but is distinct in having large, single-noded, spherical, succulent pseudobulbs flattened on the substratum, pendent and densely pubescent inflorescence, lowermost lip, and lip veins directed to the lip base. Results of phylogenetic analyses based on plastid markers validate the reason for a new genus. Keys for determination of all genera of the subtribe Polystachyinae and both species of Chelystachya are included. Two new combinations are made. A comprehensive description and full synonymy, as well as detailed ecological, phenological and distribution data and a list of 125 examined specimens are provided for each taxon treated. Because Polystachya affinis Lindl. is considered a holotype of Polystachya Hook. sect. Affines Kraenzl., this name is automatically a synonym of the newly introduced generic name Chelystachya. Other species of the former section Affines are classified within the section Humiles.

Revision of Gyrodactylus salaris phylogeny inspired by new evidence for Eemian crossing between lineages living on grayling in Baltic and White sea basins

In this research, grayling-specific Gyrodactylus salaris Malmberg, 1957 isolates from Baltic Sea basin were collected in Sweden for the first time. Samples were obtained in three drainage systems: Kalixälven (River Kaitum), Ljungan (River Sölvbacka strömmar), and Umeälven (River Juktån). Three molecular markers were analysed: nuclear ITS rDNA (Internal Transcribed Spacer) and ADNAM1 (Anonymous DNA Marker 1), and mitochondrial cox1 gene. As a result, four new mitochondrial haplotypes were identified (III-C1tt, III-C1ttht, IX-A1tt and X-A1tt). The ADNAM1 analyses resulted in revealing two new alleles (WS4 and BS9) and two new genotypes (T6 and T7). T7 seems to be an indicator of ancient crossing between Baltic and White Sea lineages of the parasite which happened during a first 3000-year period of Eemian interglacial about 130,000 years ago in the connection between Baltic and White Sea. Molecular clock estimates were adjusted, revealing the mean substitution rate and the divergence rate among branches of 3.6% (95% HPD: 2.2%–5.2%) and 7.2% per million years, respectively. As a result, cox1 phylogeny rooted with the introgressed haplotypes has been revised and altered in accordance to new data, revealing fourteen equidistant lineages five of which have been excluded from the study. Based on the new phylogenetic approach, including the molecular clock, this work suggests an overall revision of G. salaris phylogeny and attempts at precisely drawing the division of lineages within this polytypic species as well as proposes unification in nomenclature for its strains.

Taxonomical notes on Pachygenium (Orchidaceae).

Three new species of the orchid genus Pachygenium are described and illustrated: Pachygenium schmidtianum Mytnik, Szlach. & Górniak, P. triangulare Mytnik, Szlach. & Górniak and P. arechavaletae Mytnik, Szlach. & Górniak. A new combination on the species level, Pachygenium callosum (M.N. Correa) Mytnik, Szlach. & Górniak is validated. The taxonomic position of the new taxa is briefly discussed. Pachygenium is compared in a table with Pelexia on the generic level. A brief taxonomic history of Pachygenium is presented.