Seed dispersal and realized gene flow of two forest orchids in a fragmented landscape

This thesis investigates the dispersal abilities of mycoheterotrophic plants represented by three orchid species. Seed trapping and gene flow study were used to examine this topic

Factors limiting the distribution of the mycoheterotrophic plants in fragmented landscape

This thesis investigates the influence of habitat, dispersal abilities and evolution on distribution of mycoheterotrophic plants represented by six orchid species. Several methods including seed trapping, in situ seed germination, fungal barcoding, gene flow study and stable isotopes analyses were used to examine this topic. The final synthesis of these approaches shows lower limitation by dispersal abilities and stronger limitation by habitat

Germination course and mycorrhizal association of two \kur{Neottia} species

Germination course and mycorrhizal partners during germination and adulthood were studied in Neottia ovata and N. cordata. Neottia ovata was studied in two different biotops: meadows and forests. Research was conducted in in situ conditions in the Šumava and the Smrčiny mountains

Is orchid distribution limited by their mycorrhizal associations?

The first part of this thesis is a review on limitations of orchids by their myccorhizal symbiosis. The second part presents on outline of my master thesis, which is focused on ecology and myccorhizal partners of two Listera species

Data-Smilauer_etal_2019_NewPhytol_NGS_Exp1

ZIP archive with data files included in two formats (MS Excel and comma-separated-values format

Two widespread green <i>Neottia</i> species (Orchidaceae) show mycorrhizal preference for Sebacinales in various habitats and ontogenetic stages

Plant dependence on fungal carbon (mycoheterotrophy) evolved repeatedly. In orchids, it is connected with a mycorrhizal shift from rhizoctonia to ectomycorrhizal fungi and a high natural 13C and 15N abundance. Some green relatives of mycoheterotrophic species show identical trends, but most of these remain unstudied, blurring our understanding of evolution to mycoheterotrophy. We analysed mycorrhizal associations and 13C and 15N biomass content in two green species, Neottia ovata and N. cordata (tribe Neottieae), from a genus comprising green and nongreen (mycoheterotrophic) species. Our study covered 41 European sites, including different meadow and forest habitats and orchid developmental stages. Fungal ITS barcoding and electron microscopy showed that both Neottia species associated mainly with nonectomycorrhizal Sebacinales Clade B, a group of rhizoctonia symbionts of green orchids, regardless of the habitat or growth stage. Few additional rhizoctonias from Ceratobasidiaceae and Tulasnellaceae, and ectomycorrhizal fungi were detected. Isotope abundances did not detect carbon gain from the ectomycorrhizal fungi, suggesting a usual nutrition of rhizoctonia-associated green orchids. Considering associations of related partially or fully mycoheterotrophic species such as Neottia camtschatea or N. nidus-avis with ectomycorrhizal Sebacinales Clade A, we propose that the genus Neottia displays a mycorrhizal preference for Sebacinales and that the association with nonectomycorrhizal Sebacinales Clade B is likely ancestral. Such a change in preference for mycorrhizal associates differing in ecology within the same fungal taxon is rare among orchids. Moreover, the existence of rhizoctonia-associated Neottia spp. challenges the shift to ectomycorrhizal fungi as an ancestral pre-adaptation to mycoheterotrophy in the whole Neottieae

Neottia_ITS_alignment

Alignment of ITS sequences of several Neottieae species produced by MAFFT and used for infering Neottia phylogeny. This file is in nexus format and contains sequence alignment and MrBayes input data

Sebacinales_28S_alignment

Alignment of 28S sequences of Sebacinales produced by MAFFT and used for infering Sebacinales phylogeny. This file is in nexus format and contains sequence alignment and MrBayes input data

Data from: Two widespread green Neottia species (Orchidaceae) show mycorrhizal preference for Sebacinales in various habitats and ontogenetic stages

Plant dependence on fungal carbon (mycoheterotrophy) evolved repeatedly. In orchids, it is connected with a mycorrhizal shift from rhizoctonia to ectomycorrhizal fungi and a high natural 13C and 15N abundance. Some green relatives of mycoheterotrophic species show identical trends, but most of these remain unstudied, blurring our understanding of evolution to mycoheterotrophy. We analyzed mycorrhizal associations and 13C and 15N biomass content in two green species, Neottia ovata and N. cordata (tribe Neottieae), from a genus comprising green and non-green (mycoheterotrophic) species. Our study covered 41 European sites, including different meadow and forest habitats and orchid developmental stages. Fungal ITS barcoding and electron microscopy showed that both Neottia species associated mainly with non-ectomycorrhizal Sebacinales Clade B, a group of rhizoctonia symbionts of green orchids, regardless of the habitat or growth stage. Few additional rhizoctonias from Ceratobasidiaceae and Tulasnellaceae, and ectomycorrhizal fungi were detected. Isotope abundances did not detect carbon gain from the ectomycorrhizal fungi, suggesting a usual nutrition of rhizoctonia-associated green orchids. Considering associations of related partially or fully mycoheterotrophic species such as Neottia camtschatea or N. nidus-avis with ectomycorrhizal Sebacinales Clade A, we propose that the genus Neottia displays a mycorrhizal preference for Sebacinales, and that the association with non-ectomycorrhizal Sebacinales Clade B is likely ancestral. Such a change in preference for mycorrhizal associates differing in ecology within the same fungal taxon is rare among orchids. Moreover, the existence of rhizoctonia-associated Neottia spp. challenges the shift to ectomycorrhizal fungi as an ancestral pre-adaptation to mycoheterotrophy in the whole Neottieae

Sebacinales_28S_tree

Bayesian majority-rule consensus tree of Sebacinales based on part of 28S. The tree is in newick format