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•We characterize two hybridogenous, sexual and allotetraploid Diphasiastrum spp.•D. wightianum is allotetraploid and originates from D. veitchii × D. multispicatum.•D. yueshanense is ...part of a hybrid complex of D. veitchii and an unknown parent.•Flow cytometry, cp + nc markers and MIG-seq reveal triploid and tetraploid taxa.•We present an evolutionary scheme to explain the complex speciation events.
In the species groups related to Diphasiastrum multispicatum and D. veitchii, hybridization was investigated in samples from northern and southern Vietnam and the island of Taiwan, including available herbarium specimens from southeast Asia. The accessions were analyzed using flow cytometry (living material only), Sanger sequencing and multiplexed inter-simple sequence repeat genotyping by sequencing. We detected two cases of ancient hybridization involving different combinations of parental species; both led via subsequent duplication to tetraploid taxa. A cross D. multispicatum × D. veitchii from Malaysia represents D. wightianum, a tetraploid taxon according to reported DNA content measurements of dried material (genome formulas MM, VV and MMVV, respectively). The second case involves D. veitchii and an unknown diploid parent (genome formula XX). Three hybridogenous taxa (genome formulas VVX, VVXX, VVVX) were discernable by a combination of flow cytometry and molecular data. Taxon I (VVX, three clones found on Taiwan island) is apparently triploid. Taxon II represents another genetically diverse and sexual tetraploid species (VVXX) and can be assigned to D. yueshanense, described from Taiwan island but occurring as well in mainland China and Vietnam. Taxon III is as well most likely tetraploid (VVVX) and represented by at least one, more likely two, clones from Taiwan island. Taxa I and III are presumably asexual and new to science. Two independently inherited nuclear markers recombine only within, not between these hybrids, pointing towards reproductive isolation. We present an evolutionary scheme which explains the origin of the hybrids and the evolution of new and fully sexual species by hybridization and subsequent allopolyploidization in flat-branched clubmosses.
Nivicolous myxomycete assemblages were surveyed on the northwest of the Greater Caucasian ridge in May-June 2010 and 2011 at a north facing transect between 1,700 and 2,920 m elevation of the summit ...Malaya Khatipara situated within the Teberda State Biosphere Reserve. Morphological characters of 396 collections representing 45 taxa (39 species, 3 varieties, and 3 forms) of myxomycetes in 8 genera and 5 families were recorded. Many (13) taxa are classified as rare (a species represents <0.5 % of all records). Only seven species were found to be widely distributed (present in 50 % or more of the 17 studied localities). To confirm the assignment of specimens to morphospecies, we obtained independently from determination 145 partial sequences of the 18S SSU rRNA gene from 35 taxa of
Lamproderma
,
Meriderma
,
Physarum
and
Diderma
, which turned out to represent 58 genotypes. Most of the taxa represented by more than one sequence had several genotypes, with an average of 1.7 genotypes per taxon. Except for three taxonomically difficult groups of species, partial SSU sequences did well correspond with the respective morphospecies and where similar or identical to sequences of specimens from the European Alps, making this marker a good candidate for barcoding in myxomycetes. Species richness and diversity increased from subalpine crooked-stem birch forests (23 species, 2 varieties,
H
′ = 2.8,
E
= 0.88,
D
= 0.08) to alpine dwarf shrub communities (34 species and 2 varieties, 2 forms,
H
′ = 3.2,
E
= 0.89,
D
= 0.05) but decreased again for alpine meadows (27 species and 2 varieties, 2 forms,
H
′ = 3.1,
E
= 0.91,
D
= 0.06). Species richness and alpha-diversity reached maximum values for ground litter, whereas leaves and stems of living shrubs above ground harboured a more depauperate myxomycete assemblage.
A study including eight microsatellite loci for 1,014 trees from seven mapped stands of the partially clonal Populus euphratica was used to demonstrate how genotyping errors influence estimates of ...clonality. With a threshold of 0 (identical multilocus genotypes constitute one clone) we identified 602 genotypes. A threshold of 1 (compensating for an error in one allele) lowered this number to 563. Genotyping errors can seemingly merge (type 1 error), split really existing clones (type 2), or convert a unique genotype into another unique genotype (type 3). We used context information (sex and spatial position) to estimate the type 1 error. For thresholds of 0 and 1 the estimate was below 0.021, suggesting a high resolution for the marker system. The rate of genotyping errors was estimated by repeated genotyping for a cohort of 41 trees drawn at random (0.158), and a second cohort of 40 trees deviating in one allele from another tree (0.368). For the latter cohort, most of these deviations turned out to be errors, but 8 out of 602 obtained multilocus genotypes may represent somatic mutations, corresponding to a mutation rate of 0.013. A simulation of genotyping errors for populations with varying clonality and evenness showed the number of genotypes always to be overestimated for a system with high resolution, and this mistake increases with increasing clonality and evenness. Allowing a threshold of 1 compensates for most genotyping errors and leads to much more precise estimates of clonality compared with a threshold of 0. This lowers the resolution of the marker system, but comparison with context information can help to check if the resolution is sufficient to apply a higher threshold. We recommend simulation procedures to investigate the behavior of a marker system for different thresholds and error rates to obtain the best estimate of clonality.
A systematic survey for myxomycetes in winter-cold deserts and steppes of western Mongolia resulted in a total of 333 records belonging to 36 species from 13 genera and 7 families. Physarum notabile ...as the most common species was recorded 72 times, but about one third of all species was classified as rare for the whole study area. Due to the very arid climate of the region, all specimens were obtained by applying the moist chamber culture technique. Maximum values for diversity and species richness were recorded in dry steppe/shrub and mountain steppe/tall shrub communities, whereas extrazonal grasslands and alpine steppes had the most depauperate myxomycete biota. Among three different groups of substrata (bark of shrubs, ground litter, and dung of herbivores) diverging trends in species richness and substrate specificity of the species were found: bark had the richest but least specific, dung the poorest but most specific myxomycete assemblage. A hierarchical cluster analysis carried out on the incidence-based Chao-S0erensen index clearly indicates a separation between myxomycete biotas of Eurasian, western North American and South American deserts, supporting the moderate endemicity model postulated for various other groups of microbes and protists.
We have studied the influence of the stage of decomposition and acidity of wood, as well as the illumination of the microhabitat on the species composition, abundance, and occurrence of slime molds ...(Myxomycetes) of the xylobiontic (inhabitants of the wood) substrate complex of forest communities in Siberia (Altai krai, Altai Republic, and Novosibirsk oblast). This work is based on a study of 1777 samples of fruit bodies (sporophores) of myxomycetes. In the analysis of data for communities of Myxomycetes of the xylobiontic substrate complex, we recognize a successional series which clearly correlates with the stage of wood decomposition. The study of the distribution of the species composition of the slime mold on wood of various stages of decomposition shows that the maximum number of species is observed on dead trunks where the wood is of medium density and the bark can easily be separated (W3). The lowest specificity and diversity of species composition is observed on the fallen trunks of trees with very dense wood and dense bark (W1). These dead trees have low water-retaining capacity, tight bark, and almost intact wood containing large amounts of lignin, preventing the invasion of plasmodia and myxamoebae of Myxomycetes into the trunk. A study of the location of slime-mold colonies in relation to the illumination level shows that the greatest number of species is found on the front, side, and bottom parts of dead trunks of woody plants. The least specificity and the least variety of Myxomycetes species are found on apical parts of dead tree trunks facing the sun. The exception are species with large fruit bodies such as
Fuligo septica
and
Reticularia splendens
, which are most often observed on the upper parts of the sun facing trunks of woody plants. In the research area, the complex of species typical for wood of coniferous trees is described. It is noted that acidophilic slime molds of the genera
Comatricha
and
Cribraria
can be traced in xylobiontic and epiphytic–corticuloid substrate complexes.
Abundance and habitat requirements of nivicolous myxomycetes were surveyed over 4 yr at the northwestern Greater Caucasus ridge (Russia). An elevational transect spanning 3.66 km from 1 700 to ...3 000 m a.s.l. was established at the summit Malaya Khatipara situated within the Teberda State Biosphere reserve. Between 2010 and 2013 1177 fructifications of nivicolous myxomycetes were recorded, with 700 of these determined to 44 species, varieties, and forms. Virtually all fructifications developed near or at the margin of a snow field. Abundance of myxomycete fructifications varied extremely between years, ranging from near zero to hundreds of colonies. At sites with known myxomycete occurrences 16 data loggers were installed in the years 2011 and 2012, measuring relative humidity and temperature at the soil surface. Together with weather data recorded on the nearby Klukhor pass and experiments with myxamoebae cultured on agar, these data explain the observed extreme fluctuations in myxomycete abundance. A sudden frost (one night below −10 °C) occurring before the first lasting snow in Nov. 2011 was most likely the reason for the nearly complete absence of myxomycete fruiting in spring 2012. Culture experiments showed that amoebae survived a slow decrease in temperature, as occurs under a sheltering snow cover, but are killed by sudden freezing. Extreme temperature changes recorded at the margin of snow fields explain why nivicolous myxomycetes must fruit before snow melt is complete, and the different transmittance of snow packs for light of different wave lengths may be crucial for triggering the formation of fruiting bodies. The high abundance of fructifications in nivicolous myxomycetes suggests them to be important predators of microbial communities under snow.
Tugai forests are the riparian forests along the rivers in the continental desert regions of Central Asia, i.e. the Tarim River, Amu Darya and Syr Darya. They mainly consist of Populus euphratica ...Oliv., Populus pruinosa Schrenk. and Elaeagnus oxycarpa Schltdl. As a consequence of land opening campaigns, large areas of Tugai forests were destroyed after the 1950s. Due to excessive use of water for irrigation, the remaining Tugai forests are under severe threat. Near natural Tugai forests still exist along the Tarim middle reaches in the Tarim Huyanglin Nature Reserve, Xinjiang, NW China. There is a gap in understanding, how the seedlings of P. euphratica establish as trees which continuously connect to the groundwater. Therefore, the set of conditions which must be met for germination and successful establishment, i.e. formation of Tugai forests, was investigated along a representative transect still under natural conditions. P. euphratica seedlings germinate in belts during the retreat of the summer flood on freshly deposited sites bare of other vegetation. Such germination sites are formed by river dynamics. While germination takes place regularly in the study area, successful establishment is restricted to few germination events. Seedlings face dropping groundwater levels during spring and early summer of the second year after germination. Therefore, for successful establishment, it is essential that the flood of the second year starts in time and is high enough, in order to replenish the groundwater. Furthermore, clayey soil layers in the subsoil may play a role for successful establishment, too, as they store water better than sandy soil layers.
A joint analysis considering the world-wide distribution and threat status of Central European vascular plants was carried out to derive conservation priorities for threatened species. A list of 417 ...taxa is presented, which are threatened throughout Central Europe and/or show a predominantly Central European distribution. As a first step, all plants mentioned in Central European national Red Lists were included in a synoptic table, resulting in a total of 3255 taxa threatened or rare in at least one country. To select species with a high conservation priority, two parameters were estimated: threat status for Central Europe and a new category termed responsibility for the conservation of a species. As criteria for this second parameter, we used the proportion of Central Europe on the world range of a species, the position of Central Europe within this range, and its world-wide threat status. A simple category system including four responsibility categories is proposed. For all species selected, threat status and a responsibility assessment for the whole of Central Europe is given, as well as position and proportion of Central Europe on their world range. By comparison of threat status and responsibility, this list provides a background for assessing national conservation priorities as well as for making decisions about inclusion in international conventions on species conservation. This was shown by a comparison of the species selected using this approach with those included in the two most important European instruments for species conservation - the Berne Convention and the Habitats Directive.PUBLICATION ABSTRACT
Many microfungi are able to live in living plant tissues. In contrast to plant pathogens and parasites the so-called endophytic fungi do not cause obvious disease symptoms in their hosts. ...Nevertheless, they constitute an ubiquitous active component in direct and multitrophic interactions. The present study was conducted to assess the level of overlap of cultivable microfungi in living and decaying tissues of European Beech (
Fagus sylvatica
L.) from a forest stand in North-Eastern Germany. The focus lay on the hypothesized fall-spring relationship of leaf-inhabiting forest endophytes, which means that endophytes from autumn leaves persist as saprobes in litter or dead wood, sporulate and re-invade living leaves in spring. Fungal cultures were isolated from living leaves, leaf litter and dead wood still attached to the tree by dilution-to-extinction cultivation in the years 2007–2010. Analyses of species identity, species richness and species composition were based on microscopic identification and of sequencing the fungal DNA ‘barcode’ ITS (internal transcribed spacer). Species richness of litter-inhabiting microfungi equaled that of wood-inhabiting fungi and exceeded that of leaf endophytes. The most distinctive species assemblage was observed on wood, fungal species composition in living leaves and leaf litter were also significantly different from each other. On the other hand a considerable compositional and phylogenetic overlap between leaf and litter fungi was revealed with phylogenetics, cluster analysis and non-metric multidimensional scaling. The taxa accounting most to the similarity between living and decaying leaves belonged to Capnodiales, Xylariales, Diaporthales and Pleosporales. Finally, data from cultivated leaf-inhabiting beech endophytes were compared with a fungal 454 sequence data set from beech phyllosphere. This analysis allowed the partition of species lists into active fungal endophytes, fungal “epiphytes” and dormant fungal propagules.
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