Species composition and distribution of Coleosporium species on the needles of Pinus densiflora at a semi-natural vegetation succession site in central Japan

Coleosporium species cause pine needle rust. Most species have heteromacrocyclic life cycles, and 12 species use Pinus densiflora as aecial hosts. To understand the biology of rust fungi and develop better methods for controlling rust diseases, it is necessary to clarify that which Coleosporium species affect pine trees. However, Coleosporium on pine trees have rarely been identified at the species level because of their morphological similarities. We used polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) to clarify the species composition, abundance, and distribution of Coleosporium in a P. densiflora forest. We surveyed a site where several Coleosporium species might complete their life cycles. PCR-RFLP revealed four species on the pines: C. asterum, C. clematidis-apiifoliae, C. lycopodis, and C. phellodendri. Coleosporium phellodendri was distributed throughout the forest and was the most abundant. Aecia of C. phellodendri formed mainly on 2-y-old needles. The abundance and distribution of C. phellodendri appeared to be affected by the longer effective dispersal range of basidiospores and the existence of abundant inoculum sources. The age of leaves where C. phellodendri form aecia mainly was thought to be influenced by the characteristic life cycle, with aecial formation requiring 2?y after basidiospore infection.     

Are the microcyclic rust species Puccinia melampodii and Puccinia xanthii conspecific?

The taxonomic relationship between two microcyclic rust species, Puccinia melampodii and Puccinia xanthii, recorded from a number of Asteraceae hosts, was explored by comparing teliospore morphology, host specificity and sequence data. Teliospore morphology varied between and within individual rust accessions but, in general, teliospores of P. xanthii were larger than those of P. melampodii. Field observations and cross-inoculation greenhouse studies showed that P. melampodii accessions were highly specific to their original host species and unable to establish compatible interactions with related Asteraceae species. Though small amounts of genetic variation were detected between P. melampodii and P. xanthii accessions, the ITS and TEF phylogenetic analyses comprising several other rust species grouped these accessions within a well supported clade. Our data indicate that despite differences between P. xanthii and P. melampodii accessions these rusts cannot readily be separated at the species level, supporting earlier taxonomic conclusions and the recent proposal to group them into a morphospecies. Based on host-specificity data, the name Puccinia xanthii var. parthenii-hysterophorae is proposed to accommodate all Mesoamerican records of P. melampodii associated with the host Parthenium hysterophorus.     

Detection of a root-associated group of Hyaloscyphaceae (Helotiales) species that commonly colonizes Fagaceae roots and description of three new species in genus Glutinomyces

We used a culture-dependent approach to investigate root-associated fungal communities in Fagaceae roots at four fagaceous species-dominant forests in Japan. In total 1029 isolates were collected and classified, based on colony morphological features and molecular information. Species of order Helotiales (Ascomycota) were dominantly isolated at all four sites, in which a globally-distributed putative endophytic group in Hyaloscyphaceae predominated. This group of fungi was morphologically and phylogenetically investigated using these isolates as well as additional isolates collected from 8 different sites in Japan. Among the Hyaloscyphaceae, Glutinomyces species were frequently detected, and three novel species, G. inflatus, G. vulgaris, and G. takaragaikensis spp. nov. were identified and described according to their morphology and genealogical concordance.     

Genetic diversity and phylogenetic relations of salmon trematode Nanophyetus japonensis

Nanophyetiasis is the severe zoonotic disease caused by parasitic worms from the genus Nanophyetus. Humans and carnivorous animals become infected when they ingest raw fish containing metacercariae, especially Pacific salmonids. Nanophyetiasis is detected in limited geographical areas which include the coastal regions of the North Pacific: the United States of America, Russian Federation and Japan. Despite the epidemiological significance, Nanophyetus species have not been well studied genetically. In this research, we for the first time explored genetic diversity of Nanophyetus japonensis from Japan in comparison with those of related species, N. salmincola from North America and N. schikhobalowi from the Russian Far East, based on sequence variation in the nuclear ribosomal gene family (18S, ITS1–5.8S–ITS2 and 28S) and mitochondrial nad1 gene, encoding subunit I of the respiratory chain NADH dehydrogenase. The results confirmed the independent species status for the compared flukes, demonstrated a greater genetic similarity of Asian species between themselves than each of them with the North American one, suggesting that N. japonensis and N. schikhobalowi are close sister species, and also revealed discrepancy between the levels of morphological and genetic differentiation.     

Discriminant analysis of volatile organic compounds of Fusarium oxysporum f. sp. cepae and Fusarium proliferatum isolates from onions as indicators of fungal growth

Basal rot is a common onion disease and is mainly caused by Fusarium oxysporum f. sp. cepae and Fusarium proliferatum. To study the possibility of using volatile organic compounds (VOCs) as biomarkers for these fungi, pathogenic isolates of F. oxysporum and F. proliferatum from onions were cultivated in onion medium and VOCs were measured by solid phase microextraction (SPME). Forty-two compounds were detected, and thirty of these compounds were highly related to fungal metabolic activity. Allyl mercaptan was specific to F. oxysporum isolate Fox006. Analysis of the VOCs showed significant differences between the two species and among different isolates within the same species. Sixteen of the VOCs showed were highly positively correlated with the fungal biomass estimated by real-time polymerase chain reaction (PCR). Ethanol, ethyl formate, ethyl acetate, 2-methyl-1-propanol, methyl thioacetate, n-propyl acetate and 3-methyl-1-butanol are volatile metabolites that were potential indicators of Fusarium growth on onions.     

Phylogenetic analyses of Bradyrhizobium symbionts associated with invasive Crotalaria zanzibarica and its coexisting legumes in Taiwan

In this study, the genetic diversity and identification of Bradyrhizobium symbionts of Crotalaria zanzibarica, the most widely-distributed invasive legume in Taiwan, and other sympatric legume species growing along riverbanks of Taiwan were evaluated for the first time. In total, 59 and 54 Bradyrhizobium isolates were obtained from C. zanzibarica and its coexisting legume species, respectively. Based on the multilocus sequence analysis (MLSA) of concatenated four housekeeping genes (dnaK-glnII-recA-rpoB gene sequences, 1901 bp), the 113 isolates displayed 53 unique haplotypes and grouped into 21 clades. Of these clades, 11 were found to be congruent to already defined Bradyrhizobium species, while the other 10 clades were found to not be congruent to any defined species. In particular, the C. zanzibarica isolates belong to 14 MLSA clades, six of which overlapped with the isolates of coexisting legumes. According to the nodA gene sequences (555 bp) obtained from the 105 isolates, these isolates were classified into three known nodA clades, III.2, III.3 and VII and were further clustered into 10 groups. Furthermore, the C. zanzibarica isolates were clustered into 8 nodA groups, five of which overlapped with the isolates from coexisting legumes. Additionally, the nodA genes of the isolates from native species were dominated by Asian origin, while those from C. zanzibarica were dominated by American origin. In conclusion, C. zanzibarica is a promiscuous host capable of recruiting diverse Bradyrhizobium symbionts, some of which are phylogenetically similar to the symbionts of coexisting legumes in Taiwan.     

Large Shift in Symbiont Assemblage in the Invasive Red Turpentine Beetle

Changes in symbiont assemblages can affect the success and impact of invasive species, and may provide knowledge regarding the invasion histories of their vectors. Bark beetle symbioses are ideal systems to study changes in symbiont assemblages resulting from invasions. The red turpentine beetle (Dendroctonus valens) is a bark beetle species that recently invaded China from its native range in North America. It is associated with ophiostomatalean fungi in both locations, although the fungi have previously been well-surveyed only in China. We surveyed the ophiostomatalean fungi associated with D. valens in eastern and western North America, and identified the fungal species using multi-gene phylogenies. From the 307 collected isolates (147 in eastern North America and 160 in western North America), we identified 20 species: 11 in eastern North America and 13 in western North America. Four species were shared between eastern North America and western North America, one species (Ophiostoma floccosum) was shared between western North America and China, and three species (Grosmannia koreana, Leptographium procerum, and Ophiostoma abietinum) were shared between eastern North America and China. Ophiostoma floccosum and O. abietinum have worldwide distributions, and were rarely isolated from D. valens. However, G. koreana and L. procerum are primarily limited to Asia and North America respectively. Leptographium procerum, which is thought to be native to North America, represented >45% of the symbionts of D. valens in eastern North America and China, suggesting D. valens may have been introduced to China from eastern North America. These results are surprising, as previous population genetics studies on D. valens based on the cytochrome oxidase I gene have suggested that the insect was introduced into China from western North America.     

Temperature effects on hyphal growth of wood-decay basidiomycetes isolated from Pinus densiflora deadwood

Hyphal growth rates were tested on malt extract agar plates at eight different temperatures (5–40?°C) using 36 isolates of 17 basidiomycete species obtained from Pinus densiflora deadwood in Japan. All isolates of four brown rot species showed optimum growth at 30?°C, whereas the optimum growth temperature of white rot species varied from 20?°C to 30?°C. Analysis using a dataset from four cooler sites showed that brown rot fungi grew more rapidly than white rot fungi at higher temperatures (25?°C, 30?°C, and 35?°C). These results suggest that the hyphal growth of brown rot fungi might be physiologically adapted to higher temperatures than those of white rot fungi among the fungal species inhabiting deadwood of P. densiflora in Japan.     

Genetic evidence for three discrete taxa of Melampsora (Pucciniales) affecting willows (Salix spp.) in New York State

Rust fungi in the genus Melampsora (Pucciniales) are the most important pathogens of shrub willows (Salix spp.) cultivated for biomass in New York State and temperate regions worldwide. The taxonomy and species identification of these fungi historically have been problematic as they are morphologically indistinguishable on willow and often have complex life histories. Melampsora of Salix in North America, therefore, have been circumscribed to the collective species Melampsora epitea Thüm. and further delineated to formae speciales by aecial host. Ribosomal DNA (rDNA) data was obtained from 75 collections/isolates of Melampsora in NY State affecting either native and cultivated Salix spp. or suspected alternate hosts. Maximum likelihood (ML), maximum parsimony (MP), and Bayesian (BI) analyses were conducted on three data partitions (individual and concatenated): complete internal transcribed spacer (ITS) and partial large subunit (LSU) rDNA sequences for all collections. Analyses of the ITS and concatenated ITS-LSU sequences revealed that Melampsora on native and cultivated willows in NY State consisted of three phylogenetically delineable taxa (phylotaxa); monophyly for each phylotaxon was strongly supported by ML, MP, and BI credibility values. Phylotaxa were also delimited phylogenetically by aecial host: Alpine currant (Ribes alpinum), eastern larch (Larix laricina), or balsam fir (Abies balsamea).     

Inhibition of virulent and hypovirulent Cryphonectria parasitica growth in dual culture by fungi commonly isolated from chestnut blight cankers

Chestnut blight cankers, caused by the fungus Cryphonectria parasitica, are prone to invasion by other microorganisms as the canker ages. This microbial community has the potential to alter canker expansion, which may influence the probability that the canker girdles the infected stem. Hypoviruses infect the pathogen mycelium directly and are known to decrease pathogen virulence (i.e. hypovirulent). These viral infections can slow pathogen growth, decreasing the rate of canker expansion and lowering the probability of girdling. Saprophytic fungi also invade the expanding canker and may antagonize C. parasitica leading to reduced pathogen growth. The combined effects of fungal antagonism and a hypovirulent pathogen could work in combination to reduce the probability of girdling the infected stem. We assessed the ability of different fungal taxa, isolated from low severity cankers, to inhibit the growth of virulent and hypovirulent forms of C. parasitica in dual culture tests on two cultural media. Percent growth inhibition of virulent C. parasitica by potentially antagonistic fungi ranged from 2 % to 34 %, while inhibition of hypovirulent C. parasitica ranged from 18 % to 54 %. Only one isolate, identified as Umbelopsis isabellina (UmbelopsisWS) inhibited the virulent form of the pathogen more than the hypovirulent form. All three Trichoderma isolates caused the greatest growth inhibition of virulent C. parasitica, but they, like all other fungal isolates tested, inhibited the hypovirulent form of the pathogen more than the virulent form. These results suggest that commonly occurring fungi in chestnut blight cankers, including Trichoderma, may inhibit the hypovirulent C. parasitica more than virulent C. parasitica. Thus, the presence of other fungi in cankers may not enhance the effect of hypovirulent C. parasitica to delay cankers from girdling a stem but instead intensify canker development.     

Contrasting effects of plant invasion on pollination of two native species with similar morphologies

Invasive plants may decrease native plant density and disrupt interactions between native plants and their pollinators. We hypothesized that invasive Solidago canadensis (Asteraceae) competes for pollination services with two confamilial species, Ixeris chinensis and Sonchus arvensis. Breeding-system studies revealed that both native species are self-incompatible. In plots with all three species we found that Solidago received the highest visitation rates. To test the hypothesis of competition for pollination in the context of reduced native density, we established 3 plots for both native species with three Solidago densities (uninvaded, 50 and 75 % invaded) and corresponding decreases in native density. We investigated the effects of varying densities of Solidago on honeybee visitation rates, number of successive visits within individual ramets, pollen-load composition on bees, and seed set. For both native species, increasing Solidago density and decreasing native density resulted in bees carrying higher ratios of Solidago pollen and in bees visiting fewer capitula prior to departing from a plant. However, for other aspects of pollination, the native species responded very differently to Solidago. With increasing Solidago and decreasing native density, Ixeris received fewer honeybee visits and produced fewer seeds, demonstrating competition for pollination, but Sonchus attracted more honeybee visits and showed a non-significant trend toward setting more seeds, suggesting facilitation. These opposing effects occurred despite similarities in the native species’ floral morphology, suggesting that the effects of invasive plants are difficult to predict. In this case the different effects may relate to Sonchus being a taller plant with larger flowers.     

Melampsora rust species on biomass willows in central and north-eastern Germany

Melampsora willow rusts are the most important fungal pathogens in short rotation coppices of biomass willows. In the past, breeding programmes for rust resistant biomass willows concentrated on the distinction of races within the forma specialis Melampsora larici-epitea f. sp. larici-epitea typica that colonized Salix viminalis and related clones. In a new breeding program that is based on a wider range of willow species it is necessary to identify further Melampsora species and formae specialis that are pathogens of willow species other than S. viminalis. Therefore, three stock collections with Salix daphnoides, Salix purpurea, and other shrub willow species (including S. viminalis) species were sampled in north-eastern Germany. A fourth stock collection in central Germany contributed rusts of tree willows (Salix fragilis and Salix alba) and the large shrub Salix caprea. Out of 156 rust samples, 149 were successfully sequenced for ITS rDNA. A phylogenetic analysis combining Neighbour-Joining, Maximum-Likelihood and Bayesian analysis revealed six species: Melampsora ribesii-purpureae, Melampsora allii-salicis-albae, Melampsora sp. aff. allii-fragilis, Melampsora larici-pentandrae, Melampsora larici-caprearum, and Melampsora larici-epitea. The first four species were found exclusively on the expected hosts. Melampsora larici-caprearum had a wider host range comprising S. caprea and S. viminalis hybrids. Melampsora larici-epitea can be further differentiated into two formae speciales. The forma specialis larici-epitea typica (59 samples) colonized Salix viminalis clones, Salix purpurea, Salix×dasyclados, and Salix×aquatica. In contrast to this relatively broad host range, f. sp. larici-daphnoides (65 samples) was found exclusively on Salix daphnoides. With the distinction and identification of the rust species/formae speciales it is now possible to test for race-specific resistances in a more targeted manner within the determined pairings of rust and willow species.     

A tale of two clades: Comparative study of Glyptodon Owen and Glyptotherium Osborn (Xenarthra,Cingulata, Glyptodontidae)

Glyptodon and Glyptotherium represent the most conspicuous taxa of late Neogene and Pleistocene glyptodonts in South America and North America, respectively. The earliest records of Glyptodon in South America are 1.07 Ma (late early Pleistocene, Calabrian), although the possibility that “Paraglyptodon uquiensis” represents a Pliocene specimen of Glyptodon cannot be rejected. Glyptotherium originated from South American ancestry in northern South America or Central America about 3.9 Ma (early late Pliocene, Zanclean) or earlier. The diversity of South American Glyptodon is currently under study, but preliminary evidence would indicate that no more than three species (G. munizi, G. elongatus and G. reticulatus) are valid, plus a possible new Andean species. In turn, according to the updated taxonomy proposed herein, Glyptotherium includes two chronospecies. The earliest species, Gl. texanum, differs only slightly from the latest species, Gl. cylindricum. The relationship of Glyptodon and Glyptotherium has been problematical since the discovery of the North American lineage, at first identified as various species of Glyptodon and later considered a separate genus. Glyptodon is recognized as a natural group and recent taxonomic and phylogenetic revisions place all North American glyptodontines into Glyptotherium. In this paper, we propose a detailed morphological comparison between the southern South American species of Glyptodon and Glyptotherium in order to identify diagnostic differences and potential synapomorphies. Both genera can be distinguished mainly by differences in the skull, mandible, dentition, dorsal carapace, and caudal armor, Glyptodon being somewhat larger than Glyptotherium. Both clades show a highly conservative evolution, which could be interpreted as an anagenesis. The scarce records of glyptodonts in Central America show more morphological affinity with Glyptotherium than with Glyptodon.     

Morphological and molecular characterisation of Puccinia lagenophorae, now present in central North America

In June 2004, a rust fungus not previously reported for Oklahoma was found occurring naturally on the weed, common groundsel, Senecio vulgaris, in pots in a commercial container nursery in northeastern Oklahoma. Host symptoms and morphology of teliospores and aeciospores of the fungus were consistent with those of Puccinia lagenophorae, a recent introduction into North America that has, as yet, been reported only on the East and West Coasts of the USA. This is the first report of the rust in central regions of North America. The rust is believed to be native to Australia and New Zealand and subsequently reported in most continents on numerous species and genera of the Asteraceae. Some authors in Europe consider the rust on Bellis as different from the one on Senecio, naming it Puccinia distincta. Our ITS1‐5.8S‐ITS2 ribosomal DNA sequence data, however, show homology with P. distincta sequences from Europe, indicating there is only one morphologically‐variable polyphagous species. Presumably, the rust was introduced into Oklahoma on infected plants from the West Coast of the USA, the source of most plant material in the commercial nursery where it was found. The rust is potentially important on several ornamental Asteraceae in North America as it has become in Europe, where it spreads rapidly throughout that continent following its introduction there in the early 1960s.     

Diversity,host associations,and phylogeography of temperate aurofusarin-producing Hypomyces/Cladobotryum including causal agents of cobweb disease of cultivated mushrooms

Temperate species of Hypomyces and Cladobotryum that produce the red pigment aurofusarin are common on agaricoid and polyporoid basidiomata of species from five orders of Agaricomycetes. Several cause cobweb disease of commercially cultivated mushrooms resulting in serious losses. We sequenced rpb1, rpb2, tef1, and FG1093 regions in 90 wild strains and 30 strains from mushroom farms, isolated from Europe, North America, Africa, Asia, Australia, and New Zealand. Multigene analyses support the distinctness of five species but reveal Hypomyces rosellus to be paraphyletic, comprising several cryptic lineages. Hypomyces rosellus s. str. is characterised by wide dispersal and gene flow across Eurasia but does not occur in North America. Instead, the lineages from the West and the East Coast appear distinct, having given rise to species inhabiting the Southern Hemisphere. Our results reveal wide misuse of the name H. rosellus, especially for cobweb isolates. The majority of these belong to Hypomyces odoratus, including a weakly supported group of fungicide-resistant strains from Europe and North America sharing identical sequence data. New collections are presented for Cladobotryum rubrobrunnescens and Cladobotryum tenue as well as Cladobotryum multiseptatum and Hypomyces dactylarioides, all previously known only from their type material. The former species pair occurs in Europe and the latter in Australia and New Zealand. Separate lineages appear to be maintained by geographic isolation in North America and temperate Australasia but by host specialisation in the species occurring sympatrically in Europe and Asia. Both specialist and generalist host use strategies have evolved in the group. Although teleomorphs are known in most of the species and unnamed lineages, analyses of the five-gene regions suggest the prevalence of clonal reproduction in H. odoratus. This can be the reason for its success in mushroom farms, also facilitating the spread of fungicide resistance. While tef1 and rpb2 can be recommended for species delimitation, low variation, not exceeding 1 % in the whole ingroup, impeaches the use of ITS as a barcoding gene region in this group of fungi.     

Ophiostoma quercus: An unusually diverse and globally widespread tree-infecting fungus

Ophiostoma quercus (Ascomycota, Ophiostomatales) is a globally widespread, insect-vectored fungus that colonizes a wide diversity of hardwood and conifer hosts. Although the fungus is considered to be non-pathogenic, it is closely related to the fungi that cause Dutch elm disease. We examined the global diversity of O. quercus based on a ribosomal RNA marker and three unlinked gene regions. The fungus exhibited substantial morphological diversity. In addition, O. quercus had high genetic diversity in every continent from which it was collected, although the fungus was most diverse in Eurasia. There was no evidence of geographical clustering of haplotypes based on phylogenetic and network analyses. In addition, the phylogenetic trees generated based on the different markers were non-congruent. These results suggest that O. quercus has been repeatedly moved around the globe, because of trade in wood products, and that the fungal species most likely outcrosses regularly. The high genetic diversity of the fungus, as well as its ability to utilize a wide variety of arthropod vectors and colonize a tremendous diversity of tree host species makes O. quercus truly unique among ophiostomatoid fungi.     

Three new records of powdery mildews found in Mexico with one genus and one new species proposed

Cystotheca lanestris on the new host Quercus canbyi, Microidium bauhiniicola on the new host Bauhinia macranthera and an undescribed species of Phyllactinia on Mimosa aculeaticarpa have recently been collected in Mexico. Analyses of morphological traits and molecular sequence data led to identifications of the causal agents of the powdery mildew diseases involved. Microidium bauhiniicola, hitherto only known from Argentina and Brazil, is new to Mexico. The phylogenetic analysis revealed an isolated position distant from Microidium indicating an undescribed genus, which is introduced as Bulbomicroidium gen. nov. Sequences derived from a Mexican specimen of C. lanestris on Quercus canbyi agree completely with other North American sequences, but differ from sequences retrieved from Asian collections, suggesting that C. lanestris in Asia is not conspecific with C. lanestris s. str. in North America. A new species of Phyllactinia on Mimosa malacophylla is morphologically similar to P. dalbergiae but readily distinguishable by differences in the asexual morph. Based on morphological peculiarities and results of molecular sequence analyses, this species is described as Phyllactinia mimosae sp. nov.     

Clarireedia: A new fungal genus comprising four pathogenic species responsible for dollar spot disease of turfgrass

Dollar spot is one of the most destructive and economically important fungal diseases of amenity turfgrasses. The causal agent was first described in 1937 as the ascomycete Sclerotinia homoeocarpa. However, the genus-level taxonomic placement of this fungus has been the subject of an ongoing debate for over 75 y. Existing morphological and rDNA sequence evidence indicates that this organism is more appropriately placed in the family Rutstroemiaceae rather than the Sclerotiniaceae. Here we use DNA sequence data from samples of the dollar spot fungus and other members of the Rutstroemiaceae (e.g. Rutstroemia, Lanzia, Lambertella) collected throughout the world to determine the generic identity of the turfgrass dollar spot pathogen. Phylogenetic evidence from three nucleotide sequence markers (CaM, ITS and Mcm7; 1810-bp) confirmed that S. homoeocarpa is not a species of Sclerotinia; nor is it a member of any known genus in the Rutstroemiaceae. These data support the establishment of a new genus, which we describe here as Clarireedia gen. nov. The type species for the genus, Clarireedia homoeocarpa comb. nov., is described to accommodate the dollar spot fungus, and a neotype is designated. Three new species in this clade, Clarireedia bennettii sp. nov., Clarireedia jacksonii sp. nov., and Clarireedia monteithiana sp. nov. that also cause dollar spot disease are described. Clarireedia homoeocarpa and C. bennettii occur primarily on Festuca rubra (C3 grass) hosts and appear to be restricted to the United Kingdom. Clarireedia jacksonii and C. monteithiana occur on a variety of C3 and C4 grass hosts, respectively, and appear to be globally distributed. This resolved taxonomy puts to rest a major controversy amongst plant pathologists and provides a foundation for better understanding the nature and biology of these destructive pathogens.     

Phylogenetic positions of rust fungi parasitic on ferns: Evidence from 18S rDNA sequence analysis

Molecular phylogenetic analyses of fern rusts were carried out based on 18S rDNA sequences. We sequenced the 18S rDNAs of fern rusts (Hyalopsora polypodii andUredinopsis intermedia) and non-fern rusts (Aecidium epimedii, Coleosporium asterum, Ochropsora kraunhiae, Puccinia suzutake andPhysopella ampelopsidis) and analyzed their phylogenetic relationships with other members of the Urediniomycetes. Our bootstrapped neighbor-joining tree obtained from these analyses showed that rust fungi were apparently monophyletic at high confidence level (100% bootstrap confidence). In this molecular phylogenetic tree, the two fern rusts did not occupy the basal position within the rust fungal lineage and did not form a monophyletic lineage. Two species of the Cronartiaceae (Peridermium harknessii, Cronartium ribicola) and one species of the Coleosporiaceae (Coleosporium asterum) grouped with the fern rusts. Therefore, our results suggested that the two fern rusts were not primitive. On the other hand,Mixia osmundae, which is parasitic on the primitive fernOsmunda, was phylogenetically far from the fern rusts.     

Unveiling Gymnosporangium corniforme, G. unicorne, and G. niitakayamense sp. nov. in Taiwan

Three rust fungi from high mountains and pear-producing areas in Taiwan were described using morphological and molecular data based on 34 specimens. Gymnosporangium corniforme was demonstrated to produce spermogonia and aecia on Sorbus randaiensis based on molecular analyses and inoculation experiments. The pear rust pathogen G. unicorne was discovered in Taiwan for the first time. Gymnosporangium niitakayamense sp. nov. was observed on the leaves of Photinia niitakayamensis. It was distinct from other species in peridial cell wall structures, i.e., smooth outer wall, rugose side wall, and coralloid projections on the inner wall, and in having echinulate aeciospores.