Dataset Information

Differences in mycorrhizal communities between Epipactis palustris, E. helleborine and its presumed sister species E. neerlandica.

ABSTRACT: In orchid species that have populations occurring in strongly contrasting habitats, mycorrhizal divergence and other habitat-specific adaptations may lead to the formation of reproductively isolated taxa and ultimately to species formation. However, little is known about the mycorrhizal communities associated with recently diverged sister taxa that occupy different habitats.In this study, 454 amplicon pyrosequencing was used to investigate mycorrhizal communities associating with Epipactis helleborine in its typical forest habitat and with its presumed sister species E. neerlandica that almost exclusively occurs in coastal dune habitats. Samples of the phylogenetically more distant E. palustris, which co-occurred with E. neerlandica, were also included to investigate the role of habitat-specific conditions on mycorrhizal communities.A total of 105 operational taxonomic units (OTUs) of putative orchid mycorrhizal fungi were observed in the three studied species. The majority of these fungi were endophytic fungi of Helotiales and ectomycorrhizal fungi belonging to Thelephoraceae, Sebacinaceae and Inocybaceae. In addition, a large number of other ectomycorrhizal taxa were detected, including Cortinarius, Cenococcum, Tuber, Geopora, Wilcoxina, Meliniomyces, Hebeloma, Tricholoma, Russula and Peziza Mycorrhizal communities differed significantly between the three species, but differences were most pronounced between the forest species (E. helleborine) and the two dune slack species (E. neerlandica and E. palustris).The results clearly showed that recently diverged orchid species that occupy different habitats were characterized by significantly different mycorrhizal communities and call for more detailed experiments that aim at elucidating the contribution of habitat-specific adaptations in general and mycorrhizal divergence in particular to the process of speciation in orchids.

SUBMITTER: Jacquemyn H

PROVIDER: S-EPMC4934391 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature

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Differences in mycorrhizal communities between Epipactis palustris, E. helleborine and its presumed sister species E. neerlandica.

Jacquemyn Hans H Waud Michael M Lievens Bart B Brys Rein R

Annals of botany 20160305 1

<h4>Background and aims</h4>In orchid species that have populations occurring in strongly contrasting habitats, mycorrhizal divergence and other habitat-specific adaptations may lead to the formation of reproductively isolated taxa and ultimately to species formation. However, little is known about the mycorrhizal communities associated with recently diverged sister taxa that occupy different habitats.<h4>Methods</h4>In this study, 454 amplicon pyrosequencing was used to investigate mycorrhizal ...[more]

PMID: 26946528

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Project description:Background and aimsIn the Mediterranean basin, the Italian peninsula has been suggested to be one of the most important glacial refugia for temperate tree species. The orchid genus Epipactis is widely represented in the Italian peninsula by widespread species and several endemic, localized taxa, including selfing and outcrossing taxa. Here the phylogenetic and phylogeographic relationships in a group of closely related taxa in Epipactis are investigated with the aim of understanding the role of this refugial area for cladogenesis and speciation in herbaceous species, such as terrestrial orchids.MethodsRibosomal DNA (rDNA) was employed to assess phylogenetic relationships, and plastid sequence variation in the rbcL-accD spacer was used to reveal phylogeographic patterns among plastid haplotypes using a parsimony network.Key resultsLow genetic variation and shared ribotypes were detected in rDNA, whereas high levels of sequence variation and a strong phylogeographic structure were found in the examined plastid region. The parsimony plastid haplotype network identified two main haplotype groups, one including E. atrorubens/microphylla/muelleri/leptochila and the other including all accessions of E. helleborine and several localized and endemic taxa, with a combination of widespread and rare haplotypes detected across the Italian peninsula. A greater genetic divergence separated the Italian and other European accessions of E. helleborine.ConclusionsPhylogenetic and phylogeographic patterns support a working hypothesis in which the Italian peninsula has only recently been colonized by Epipactis, probably during the most recent phase of the Quaternary age and, nevertheless, it acted as a remarkable centre of diversification for this orchid lineage. Changes in pollination strategy and recurrent shifts in mating system (from allogamy to autogamy) could have represented the mechanism promoting this rapid diversification and the observed high taxonomic complexity detected in the E. helleborine species complex.

Project description:BACKGROUND: Populus euphratica Oliv and P. pruinosa Schrenk (Salicaceae) both grow in dry desert areas with high summer temperatures. However, P. euphratica is distributed in dry deserts with deep underground water whereas P. pruinosa occurs in deserts in which there is underground water close to the surface. We therefore hypothesized that these two sister species may have evolved divergent regulatory and metabolic pathways during their interaction with different salt habitats and other stresses. To test this hypothesis, we compared transcriptomes from callus exposed to 24 h of salt stress and control callus samples from both species and identified differentially expressed genes (DEGs) and alternative splicing (AS) events that had occurred under salt stress. RESULTS: A total of 36,144 transcripts were identified and 1430 genes were found to be differentially expressed in at least one species in response to salt stress. Of these DEGs, 884 and 860 were identified in P. euphratica and P. pruinosa, respectively, while 314 DEGs were common to both species. On the basis of parametric analysis of gene set enrichment, GO enrichment in P. euphratica was found to be significantly different from that in P. pruinosa. Numerous genes involved in hormone biosynthesis, transporters and transcription factors showed clear differences between the two species in response to salt stress. We also identified 26,560 AS events which were mapped to 8380 poplar genomic loci from four libraries. GO enrichments for genes undergoing AS events in P. euphratica differed significantly from those in P. pruinosa. CONCLUSIONS: A number of salt-responsive genes in both P. euphratica and P. pruinosa were identified and candidate genes with potential roles in the salinity adaptation were proposed. Transcriptome comparisons of two sister desert poplar species under salt stress suggest that these two species may have developed different genetic pathways in order to adapt to different desert salt habitats. The DEGs that were found to be common to both species under salt stress may be especially important for future genetic improvement of cultivated poplars or other crops through transgenic approaches in order to increase tolerance of saline soil conditions.

Project description:BackgroundThe process of apophytism or spreading native species to human-made habitats is one of the main elements in the creation of plant cover in anthropogenic areas. Lately, an increase of anthropogenic localities with valuable flora has been observed. Apophytes are also members of the family Orchidaceae, especially from the genus Epipactis. The aim of the study was to (i) determine and compare the phenotypic variation of E. helleborine (L.) Crantz plants in anthropogenic and natural habitats, (ii) compare the genome size of plants growing in natural and anthropogenic habitats. The results reported in this study may indicate that a habitat influences morphological characteristics of plant species.MethodsField studies were conducted on four native stands and four stands in anthropogenic areas of E. helleborine in Poland in years 2011-2013. Biometrical analyses were performed on shoots and flowers. The flowers were characterised by 25 biometric features and measured using a Nikon SMZ 800 binocular, microscopic Moticam-1SP cameras and the MIPlus07 programme (Conbest Co.). The nuclear DNA content was determined in fresh and young leaves of E. helleborine, collected from four natural and four anthropogenic populations.ResultsWe observed that in anthropogenic populations: (i) shoots were higher than shoots from natural populations, (ii) flowers differed significantly in terms of ten biometric features between habitats, (iii) the genome size of some population differed significantly between plants growing in natural and anthropogenic habitats.DiscussionAccording to some researchers, the presence of phenotypic variability and the occurrence of ecotypes are adaptation strategies of plants to environmental changes. In our opinion, in the case of the studied anthropogenic habitats (roadside) in which the E. helleborine populations grew, we can talk about ecofen due to the often repeated set of characteristic features, i.e., high shoots, long inflorescence and long, broad leaves. We agree, however, that it is difficult to isolate a taxonomic unit for ecofen due to the lack of experimental research.

Project description:BackgroundEpipactis helleborine is an Eurasian orchid species which prefers woodland environments but it may also spontaneously and successfully colonise human-made artificial and disturbed habitats such as roadsides, town parks and gardens. It is suggested that orchids colonising anthropogenic habitats are characterised by a specific set of features (e.g., large plant size, fast flower production). However, as it is not well known how pollinator diversity and reproductive success of E. helleborine differs in populations in anthropogenic habitats compared to populations from natural habitats, we wanted to compare pollinator diversity and reproductive success of this orchid species between natural and anthropogenic habitat types.MethodsPollination biology, reproductive success and autogamy in populations of E. helleborine from anthropogenic (roadside) and natural (forest) habitats were compared. Eight populations (four natural and four human-disturbed ones) in two seasons were studied according to height of plants, length of inflorescences, as well as numbers of juvenile shoots, flowering shoots, flowers, and fruits. The number and diversity of insect pollinators were studied in one natural and two human-disturbed populations.ResultsReproductive success (the ratio of the number of flowers to the number of fruits) in the populations from anthropogenic habitats was significantly higher than in the natural habitats. Moreover, plants from anthropogenic habitats were larger than those from natural ones. In both types of populations, the main insect pollinators were Syrphidae, Culicidae, Vespidae, Apidae and Formicidae. With respect to the type of pollinators' mouth-parts, chewing (39%), sponging (34%) and chewing-sucking (20%) pollinators prevailed in anthropogenic habitats. In natural habitats, pollinators with sponging (55%) and chewing mouth-parts (32%) dominated, while chewing-sucking and piercing-sucking insects accounted for 9% and 4% respectively.DiscussionWe suggest that higher reproductive success of E. helleborine in the populations from anthropogenic habitats than in the populations from natural habitats may result from a higher number of visits by pollinators and their greater species diversity, but also from the larger size of plants growing in such habitats. Moreover, our data clearly show that E. helleborine is an opportunistic species with respect to pollinators, with a wide spectrum of pollinating insects. Summarising, E. helleborine is a rare example of orchid species whose current range is not declining. Its ability to make use of anthropogenically altered habitats has allowed its significant spatial range expansion, and even successful colonisation of North America.

Dataset Information

Differences in mycorrhizal communities between Epipactis palustris, E. helleborine and its presumed sister species E. neerlandica.

Publications

Differences in mycorrhizal communities between Epipactis palustris, E. helleborine and its presumed sister species E. neerlandica.

Similar Datasets

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