Xin-Li Wei

Antifungal Activity of Lichen-forming Fungi against Colletotrichum acutatum on Hot Pepper

Antifungal activity of Korean and Chinese lichen-forming fungi (LFF) was evaluated against plant pathogenic fungus of Colletotrichum acutatum, causal agent of anthracnose on hot pepper. This is the first attempt to evaluate antifungal activity of LFF, instead of lichen thalli, against C. acutatum. Total 100 LFF were isolated from the lichens with discharged spore method or tissue culture method. Among the 100 isolates, 8 LFF showed more than 50% of inhibition rates of mycelial growth of the target pathogen. Especially, Lecanora argentata was highly effective in inhibition of mycelial growth of C. accutatum at the rate of 68%. Antifungal activity of other LFF was in the order of Cetrelia japonica (61.4%), Ramalina conduplicans (59.5%), Umbilicaria esculenta (59.5%), Ramalina litoralis (56.7%), Cetrelia braunsiana (56.5%), Nephromopsis pallescensn (56.1%), and Parmelia simplicior (53.8%). Among the tested LFF, 61 isolates of LFF exhibited moderate antifungal activity against the target pathogen at the inhibition rates from 30 to 50%. Antifungal activity of the LFF against C. acutatum was variable at the species level rather than genus level of LFF. This study suggests that LFF can be served as a promising bioresource to develop novel biofungicides.

Diversity and distribution of lichen-associated fungi in the Ny-Ålesund Region (Svalbard, High Arctic) as revealed by 454 pyrosequencing

This study assessed the diversity and distribution of fungal communities associated with seven lichen species in the Ny-Ålesund Region (Svalbard, High Arctic) using Roche 454 pyrosequencing with fungal-specific primers targeting the internal transcribed spacer (ITS) region of the ribosomal rRNA gene. Lichen-associated fungal communities showed high diversity, with a total of 42,259 reads belonging to 370 operational taxonomic units (OTUs) being found. Of these OTUs, 294 belonged to Ascomycota, 54 to Basidiomycota, 2 to Zygomycota, and 20 to unknown fungi. Leotiomycetes, Dothideomycetes, and Eurotiomycetes were the major classes, whereas the dominant orders were Helotiales, Capnodiales, and Chaetothyriales. Interestingly, most fungal OTUs were closely related to fungi from various habitats (e.g., soil, rock, plant tissues) in the Arctic, Antarctic and alpine regions, which suggests that living in association with lichen thalli may be a transient stage of life cycle for these fungi and that long-distance dispersal may be important to the fungi in the Arctic. In addition, host-related factors shaped the lichen-associated fungal communities in this region. Taken together, these results suggest that lichens thalli act as reservoirs of diverse fungi from various niches, which may improve our understanding of fungal evolution and ecology in the Arctic.

Plant Hormones Promote Growth in Lichen-Forming Fungi

The effect of plant hormones on the growth of lichen-forming fungi (LFF) was evaluated. The use of 2,3,5-triiodobenzoic acid and indole-3-butyric acid resulted in a 99% and 57% increase in dry weight of the lichen-forming fungus Nephromopsis ornata. The results suggest that some plant hormones can be used as inducers or stimulators of LFF growth for large-scale culture.

Taxonomic Study on the Lichen Genus Cetrelia (Lecanorales, Ascomycota) in South Korea

Seventy-two lichen specimens of Cetrelia collected in South Korea since 2003 were examined by both phenotypic and phylogenetic analyses. The phenoty pic analysis was based on morphological and chemical characters, and the phylogenetic analysis was based on nrDNA ITS sequences. The result suggested that the presence and absence of isidia, soredia, lobules and medullar reaction C+ or C− are the important characters in the taxonomy of this genus. Four species of Cetrelia, C. chieitae, C. braunsiana, C. japonica, and C. pseudolivetorum have been identified in this study. Description of each species is presented with morphological and chemical characters. A key to the Cetrelia species is also presented.

Lichen-Associated Fungal Community in Hypogymnia hypotrypa (Parmeliaceae, Ascomycota) Affected by Geographic Distribution and Altitude.

Lichen-associated fungal species have already been investigated in almost all the main growth forms of lichens, however, whether or not they are homogeneous and constant within each lichen species are still inconclusive. Moreover, the related ecological factors to affect and structure the fungal composition have been poorly studied. In order to answer these questions, we took Hypogymnia hypotrypa as a model to study the relationship between the lichen-associated fungal composition and two ecological factors, i.e., site and altitude, using the method of IlluminaMiSeq sequencing. Four different sites and two levels of altitude were included in this study, and the effects of site and altitude on fungal community composition were assessed at three levels, i.e., operational taxonomic unit (OTU), class and phylum. The results showed that a total of 50 OTUs were identified and distributed in 4 phyla, 13 classes, and 20 orders. The lichen-associated fungal composition within H. hypotrypa were significantly affected by both site and altitude at OTU and class levels, while at the phylum level, it was only affected by altitude. While the lichen associated fungal communities were reported to be similar with endophytic fungi of the moss, our results indicated the opposite results in some degree. But whether there exist specific OTUs within this lichen species corresponding to different sites and altitudes is still open. More lichen species and ecological factors would be taken into the integrated analyses to address these knowledge gaps in the near future.

Limitations of Species Delimitation Based on Phylogenetic Analyses: A Case Study in the Hypogymnia hypotrypa Group (Parmeliaceae, Ascomycota).

Delimiting species boundaries among closely related lineages often requires a range of independent data sets and analytical approaches. Similar to other organismal groups, robust species circumscriptions in fungi are increasingly investigated within an empirical framework. Here we attempt to delimit species boundaries in a closely related clade of lichen-forming fungi endemic to Asia, the Hypogymnia hypotrypa group (Parmeliaceae). In the current classification, the Hypogymnia hypotrypa group includes two species: H. hypotrypa and H. flavida, which are separated based on distinctive reproductive modes, the former producing soredia but absent in the latter. We reexamined the relationship between these two species using phenotypic characters and molecular sequence data (ITS, GPD, and MCM7 sequences) to address species boundaries in this group. In addition to morphological investigations, we used Bayesian clustering to identify potential genetic groups in the H. hypotrypa/H. flavida clade. We also used a variety of empirical, sequence-based species delimitation approaches, including: the “Automatic Barcode Gap Discovery” (ABGD), the Poisson tree process model (PTP), the General Mixed Yule Coalescent (GMYC), and the multispecies coalescent approach BPP. Different species delimitation scenarios were compared using Bayes factors delimitation analysis, in addition to comparisons of pairwise genetic distances, pairwise fixation indices (FST). The majority of the species delimitation analyses implemented in this study failed to support H. hypotrypa and H. flavida as distinct lineages, as did the Bayesian clustering analysis. However, strong support for the evolutionary independence of H. hypotrypa and H. flavida was inferred using BPP and further supported by Bayes factor delimitation. In spite of rigorous morphological comparisons and a wide range of sequence-based approaches to delimit species, species boundaries in the H. hypotrypa group remain uncertain. This study reveals the potential limitations of relying on distinct reproductive strategies as diagnostic taxonomic characters for Hypogymnia and also the challenges of using popular sequence-based species delimitation methods in groups with recent diversification histories.

Taxonomic study of peltigera (peltigeraceae, ascomycota) in Korea.

Abstract A taxonomic study of Peltigera in South Korea was performed. The phylogenetic analysis based on nr DNA internal transcribed spacer sequences suggests that Peltigera is a well-supported monophyletic group. Important characteristics are the phycobiont type of thallus and the vein type at the lower cortex (wide and flat, or narrow and ridged). The vertical or horizontal arrangement of the apothecia is also important in distinguishing species in this genus. Eleven species of Peltigera were revealed and confirmed, which included one new record, P. elisabethae. A description of each species is presented with morphological, anatomic, and chemical characteristics, and comparisons between similar species are made. A key to the species is also presented.

Hypogymnia magnifica (Parmeliaceae), a new lichen from southwest China

Abstract Hypogymnia magnifica X.L.Wei & McCune is described as a new species of lichenized fungi from high elevations in Yunnan and Sichuan Provinces in southwestern China. Previously lumped under H. taiwanalpina, H. magnifica is readily distinguished from that species by its large size (commonly to 30 cm or more diam.), broad, rather appressed lobes that are contiguous to subcontiguous, sparse perforations in the upper and lateral surfaces, whitish color in the field (when dry), and lacking 3-hydroxyphysodic acid. Hypogymnia magnifica and H. taiwanalpina appear to be allopatric, with the former restricted to southwestern China and the latter restricted to far-east Asia (Taiwan and Japan).

A new species of Allocetraria (Parmeliaceae, Ascomycota) in China

Allocetraria yunnanensis R. F. Wang, X. L. Wei & J. C. Wei is described as a new species from the Yunnan Province of China, and is characterized by having a shiny upper surface, strongly wrinkled lower surface, and marginal pseudocyphellae present on the lower side in the form of a white continuous line or spot. The phylogenetic analysis based on nrDNA ITS sequences suggests that the new species is related to A. sinensis X. Q. Gao.

New Record of Lecanora muralis (Lichenized Fungus) in South Korea

Lecanora muralis was found on the rock along coastal line during the field trip in Jeju island in 2006. Thallus crustose, placodioid, closely adnate, forming orbicular patches; upper surface grayish green, glossy; central lobes areolate, marginal parts plane, edges thin pruinose; lower surface ecorticate; apothecia sessile, lecanorine type, exciple dense and intact when young, and disc plane, but when mature, exciple laciniate, disc protrudent, yellowish brown to orange, 0.5~1.5 mm in diameter; ascospores ellipsoid, simple, colorless, 12.5~15.0 × 5.0~7.5 μm. Usnic acid and zeorin contained in thallus. This is the first record of this species in South Korea.