Largest Subunit Of RNA Polymerase Research Articles

Two new brown rot polypores from tropical China.

Brown-rot fungi are types of fungi that selectively degrade cellulose and hemicellulose from wood and are perhaps the most important agents involved in the degradation of wood products and dead wood in forest ecosystem. Two new brown-rot species, collected from southern China, are nested within the clades of Fomitopsis sensu stricto and Oligoporus sensu stricto, respectively. Their positions are strongly supported in the Maximum Likelihood phylogenetic tree of the concatenated the internal transcribed spacer (ITS) regions, the large subunit of nuclear ribosomal RNA gene (nLSU), the small subunit of nuclear ribosomal RNA gene (nuSSU), the small subunit of mitochondrial rRNA gene (mtSSU), the largest subunit of RNA polymerase II (RPB1), the second largest subunit of RNA polymerase II (RPB2) and the translation elongation factor 1-α gene (TEF1) sequences. Fomitopsisbambusae, only found on bamboo, is characterised by its resupinate to effused-reflexed or pileate basidiocarps, small pores (6–9 per mm), the absence of cystidia, short cylindrical to oblong-ellipsoid basidiospores measuring 4.2–6.1 × 2–2.3 μm. Oligoporuspodocarpi is characterised by white to pale cream pore surface, round or sometimes angular pores (5–6 per mm), broadly ellipsoid to reniform basidiospores measuring 3.8–4.2 × 2–2.3 μm and growing on Podocarpus. Illustrated descriptions of these two novel species, Fomitopsisbambusae and Oligoporuspodocarpi, are provided.

DEF1: Much more than an RNA polymerase degradation factor

Degradation Factor 1 was discovered 20 years ago as a yeast protein copurifying with Rad26, a helicase involved in transcription-coupled DNA repair. It was subsequently shown to control the ubiquitylation and destruction of the large subunit of DNA damage-arrested RNA Polymerase II. Since that time, much has been learned about Def1′s role in polymerase destruction and new functions of the protein have been revealed. We now understand that Def1 is involved in more than just RNA polymerase II regulation. Most of its known functions are associated with maintaining chromosome and genomic integrity, but other exciting activities outside this realm have been suggested. Here we review this fascinating protein, describe its regulation and present a hypothesis that Def1 is a central coordinator of ubiquitin signaling pathways in cells.

Four new species in the Tremellafibulifera complex (Tremellales, Basidiomycota).

Samples of species close to Tremellafibulifera from China and Brazil are studied, and T.fibulifera is confirmed as a species complex including nine species. Five known species (T.cheejenii, T.fibulifera s.s., T. “neofibulifera”, T.lloydiae-candidae and T.olens) and four new species (T.australe, T.guangxiensis, T.latispora and T.subfibulifera) in the complex are recognized based on morphological characteristics, molecular evidence, and geographic distribution. Sequences of eight species of the complex were included in the phylogenetic analyses because T.olens lacks molecular data. The phylogenetic analyses were performed by a combined sequence dataset of the internal transcribed spacer (ITS) and the partial nuclear large subunit rDNA (nLSU), and a combined sequence dataset of the ITS, partial nLSU, the small subunit mitochondrial rRNA gene (mtSSU), the translation elongation factor 1-α (TEF1), the largest and second largest subunits of RNA polymerase II (RPB1 and RPB2). The eight species formed eight independent lineages with robust support in phylogenies based on both datasets. Illustrated description of the six species including Tremellafibulifera s.s., T. “neofibulifera” and four new species, and discussions with their related species, are provided. A table of the comparison of the important characteristics of nine species in the T.fibulifera complex and a key to the whitish species in Tremella s.s. are provided.

New taxa in Glomeromycota: Polonosporaceae fam. nov., Polonospora gen. nov., and P. polonica comb. nov.

Phylogenetic analyses of sequences of the nuc rDNA small subunit (18S), internal transcribed spacer (ITS1-5.8S-ITS2 = ITS), and large subunit (28S) region (= 18S-ITS-28S), as well as sequences of this region concatenated with sequences of the largest subunit of RNA polymerase II (RPB1) gene, proved that the species originally described as Acaulospora polonica (phylum Glomeromycota) represents a new genus and a new family of the ancient order Archaeosporales, here introduced into the Glomeromycota under the names Polonospora and Polonosporaceae, respectively. The phylogenetic analyses and BLASTn queries also indicated that the Polonosporaceae with P. polonica comb. nov. still contains several morphologically undescribed taxa at the ranks of genus and species, which have a worldwide distribution.

Novel species of Alternaria section Nimbya from Iran as revealed by morphological and molecular data

ABSTRACT In this study, the diversity of Alternaria species in section Nimbya associated with symptomatic plants in the Cyperaceae and Juncaceae families was assessed. Multilocus sequence analyses of the rDNA internal transcribed spacer (ITS) region and parts of Alternaria major allergen (Alt a 1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), second largest subunit of RNA polymerase II (RPB2), and translation elongation factor 1-alpha (TEF1) genes revealed the presence of two previously known species, A. scirpivora and A. caricicola, and three new species, which are described here as A. cypericola, sp. nov., A. heyranica, sp. nov., and A. junci-acuti, sp. nov. These new species were characterized morphologically with respect to the dimensions of conidia, the number of pseudosepta in mature conidia, and the type of conidium apical beak. According to the results of phylogenetic analyses, the presence of long, filiform true beak is not a reliable morphological indicator for grouping species in sections Alternantherae and Nimbya and phylogenetic species recognition should be used. All identified species were described, illustrated, and their morphology and phylogenetic relationships with other species in Alternaria section Nimbya were discussed.

An Overview of 24 Years of Molecular Phylogenetic Studies in Phallales (Basidiomycota) With Notes on Systematics, Geographic Distribution, Lifestyle, and Edibility.

The order Phallales (Basidiomycota) is represented by gasteroid fungi with expanded and sequestrate basidiomata, known as stinkhorns and false truffles. In phalloids, the first DNA sequence was published in 1997, and after that, some studies aimed to resolve phylogenetic conflicts and propose new species based on DNA markers; however, the number of families and genera in the order still generates controversies among researchers. Thus, this work aims to provide an overview of Phallales diversity represented by selected DNA markers available in public databases. We retrieved Phallales sequences from DNA databases (GenBank and UNITE) of seven markers: ITS (internal transcribed spacer), nuc-LSU (nuclear large subunit rDNA), nuc-SSU (nuclear small subunit rDNA), mt-SSU (mitochondrial small subunit rDNA), ATP6 (ATPase subunit 6), RPB2 (nuclear protein-coding second largest subunit of RNA polymerase), and TEF1-α (translation elongation factor subunit 1α). To compose our final dataset, all ITS sequences retrieved were subjected to BLASTn searches to identify additional ITS sequences not classified as Phallales. Phylogenetic analyses based on Bayesian and maximum likelihood approaches using single and combined markers were conducted. All ITS sequences were clustered with a cutoff of 98% in order to maximize the number of species hypotheses. The geographic origin of sequences was retrieved, as well as additional information on species lifestyle and edibility. We obtained a total of 1,149 sequences, representing 664 individuals. Sequences of 41 individuals were unidentified at genus level and were assigned to five distinct families. We recognize seven families and 22 genera in Phallales, although the delimitation of some genera must be further revisited in order to recognize only monophyletic groups. Many inconsistencies in species identification are discussed, and the positioning of genera in each family is shown. The clustering revealed 118 species hypotheses, meaning that approximately 20% of all described species in Phallales have DNA sequences available. Information related to geographic distribution represents 462 individuals distributed in 46 countries on all continents, except Antarctica. Most genera are saprotrophic with only one putative ectomycorrhizal genus, and 2.1% of the legitimate specific names recognized in Phallales are confirmed edible species. Great progress in the molecular analyses of phalloids has already been made over these years, but it is still necessary to solve some taxonomic inconsistencies, mainly at genus level, and generate new data to expand knowledge of the group.

G-Quadruplex in Gene Encoding Large Subunit of Plant RNA Polymerase II: A Billion-Year-Old Story.

G-quadruplexes have long been perceived as rare and physiologically unimportant nucleic acid structures. However, several studies have revealed their importance in molecular processes, suggesting their possible role in replication and gene expression regulation. Pathways involving G-quadruplexes are intensively studied, especially in the context of human diseases, while their involvement in gene expression regulation in plants remains largely unexplored. Here, we conducted a bioinformatic study and performed a complex circular dichroism measurement to identify a stable G-quadruplex in the gene RPB1, coding for the RNA polymerase II large subunit. We found that this G-quadruplex-forming locus is highly evolutionarily conserved amongst plants sensu lato (Archaeplastida) that share a common ancestor more than one billion years old. Finally, we discussed a new hypothesis regarding G-quadruplexes interacting with UV light in plants to potentially form an additional layer of the regulatory network.

Abstract 1269: Pharmacological targeting of transcription-replication conflict leads to anti-cancer efficacy with minimal side effects in preclinical models

Abstract Unchecked growth of cancer cells places simultaneous demands on DNA replication and transcription. Targeting the transcription-replication conflict (TRC), a major source of genome instability, could have important therapeutic implications. However, testing this hypothesis is difficult without agents directly targeting TRC. Here, we report a small molecule ligand (AOH1996) of the replisome component PCNA, which stabilizes interaction between PCNA and the large subunit (rpb1) of RNA polymerase II through the APIM motif, resulting in proteasome-dependent degradation of rpb1 and lethal DNA damages. Orally administrable, AOH1996 suppresses tumor growth without discernable toxicity at more than 10 time the compound's effective dose. In addition, AOH1996 works synergistically with known DNA damage agents to kill cancer cells. These results reveal TRC as cancer-selective vulnerability and demonstrated the therapeutic potential of AOH1996. Citation Format: Long Gu, Caroline Li, Robert Lingeman, Robert J. Hickey, Linda H. Malkas. Pharmacological targeting of transcription-replication conflict leads to anti-cancer efficacy with minimal side effects in preclinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1269.

Phylogeny and Mycotoxin Profile of Pathogenic Fusarium Species Isolated from Sudden Decline Syndrome and Leaf Wilt Symptoms on Date Palms (Phoenix dactylifera) in Tunisia.

In 2017–2018, extensive symptoms of sudden decline and fruit rot were observed on date palms in southern Tunisia. Samples of diseased plants were randomly collected in six localities. Based on morphological identification, Fusarium was the most frequent fungal genus detected. A sequencing of translation elongation factor, calmodulin, and second largest subunit of RNA polymerase II genes was used to identify 63 representative Fusarium strains at species level and investigate their phylogenetic relationships. The main species detected was Fusarium proliferatum, and at a much lesser extent, Fusarium brachygibbosum, Fusarium caatingaense, Fusarium clavum, Fusarium incarnatum, and Fusarium solani. Pathogenicity on the Deglet Nour variety plantlets and the capability to produce mycotoxins were also assessed. All Fusarium species were pathogenic complying Koch’s postulates. Fusarium proliferatum strains produced mainly fumonisins (FBs), beauvericin (BEA), and, to a lesser extent, enniatins (ENNs) and moniliformin (MON). All F. brachygibbosum strains produced low levels of BEA, diacetoxyscirpenol, and neosolaniol; two strains produced also T-2 toxin, and a single strain produced HT-2 toxin. Fusarium caatingaense, F. clavum, F. incarnatum produced only BEA. Fusarium solani strains produced MON, BEA, and ENNs. This work reports for the first time a comprehensive multidisciplinary study of Fusarium species on date palms, concerning both phytopathological and food safety issues.

Phylogenetic relationships in the genus Podoserpula and description of P. aliweni, a new species from Chile

ABSTRACT Phylogenetic analyses based on a three-locus nuclear data set (ITS1-5.8S-ITS2, the 5′ end of the 28S, and the largest subunit of RNA polymerase I) supported the pagoda fungus (Podoserpula, Amylocorticiales) as a monophyletic group most closely related to species of Anomoporia, which is nonmonophyletic, and Amyloathelia. Phylogenetic relationships inferred from internal transcribed spacer (ITS) sequences of specimens sampled in Australia, Chile, China, Madagascar, and New Zealand divided Podoserpula into two major lineages: Clade A containing Australian and New Zealand collections designated P. pusio and the Chinese species P. ailaoshanensis, which have basidiospores with no reaction to Melzer’s reagent, and Clade B, which includes a species described from Chile, P. aliweni, and specimens originating from Australia, Chile, Madagascar, and New Zealand with dextrinoid basidiospores. Podoserpula aliweni forms a unique branch in the phylogenetic tree and differs from its most closely related taxon by 1.8–2.1% in the ITS region. The new species exhibits a tree-like habit with a white to concolorous stipe-like base with the hymenophore’s main subcylindrical axis bearing up to 18 superimposed pilei, slightly enrolled white margins shading from yellowish white to orange-yellow toward the center, and ellipsoid to broadly ellipsoid basidiospores measuring 4.0–4.5 × 3.5 µm. Ecologically, P. aliweni occurs during the rainy season, often gregariously on dried branches or wet soil under Nothofagus dombeyi or N. obliqua and has a distribution range of more than 600 km in southern Chile. This study extends the known distributional range and increases our knowledge on the phylogenetic diversity and taxonomy in Podoserpula.

Molecular reassessment of diaporthalean fungi associated with strawberry, including the leaf blight fungus, Paraphomopsis obscurans gen. et comb. nov. (Melanconiellaceae)

ABSTRACTPhytopathogenic fungi in the order Diaporthales (Sordariomycetes) cause diseases on numerous economically important crops worldwide. In this study, we reassessed the diaporthalean species associated with prominent diseases of strawberry, namely leaf blight, leaf blotch, root rot and petiole blight, based on molecular data and morphological characters using fresh and herbarium collections. Combined analyses of four nuclear loci, 28S ribosomal DNA/large subunit rDNA (LSU), ribosomal internal transcribed spacers 1 and 2 with 5.8S ribosomal DNA (ITS), partial sequences of second largest subunit of RNA polymerase II (RPB2) and translation elongation factor 1-α (TEF1), were used to reconstruct a phylogeny for these pathogens. Results confirmed that the leaf blight pathogen formerly known as Phomopsis obscurans belongs in the family Melanconiellaceae and not with Diaporthe (syn. Phomopsis) or any other known genus in the order. A new genus Paraphomopsis is introduced herein with a new combination, Paraphomopsis obscurans, to accommodate the leaf blight fungus. Gnomoniopsis fragariae comb. nov. (Gnomoniaceae), is introduced to accommodate Gnomoniopsis fructicola, the cause of leaf blotch of strawberry. Both of the fungi causing leaf blight and leaf blotch were epitypified. Fresh collections and new molecular data were incorporated for Paragnomonia fragariae (Sydowiellaceae), which causes petiole blight and root rot of strawberry and is distinct from the above taxa. An updated multilocus phylogeny for the Diaporthales is provided with representatives of currently known families.

Gaeumannomyces nanograminis, sp. nov., a hyphopodiate fungus identified from diseased roots of ultradwarf bermudagrass in the United States

ABSTRACT The genus Gaeumannomyces (Magnaporthaceae, Magnaporthales, Sordariomycetes, Ascomycota) includes root-infecting pathogens, saprobes, and endophytes. Morphological, biological, and phylogenetic analyses were employed to identify fungal isolates derived from turfgrass roots colonized with ectotrophic, dark runner hyphae. Phylogenetic trees for partial sequences of the 18S nuc rDNA, ITS1-5.8S-ITS2 nuc rDNA internal transcribed spacer, and 28S nuc rDNA regions and of the minichromosome maintenance complex 7 (MCM7), largest subunit of RNA polymerase II (RPB1), and translation elongation factor 1-alpha (TEF1) genes were obtained via maximum likelihood and Bayesian methods. Our isolates consistently formed a distinct and highly supported clade within Gaeumannomyces. Common and distinctive biological and morphological characters reinforced these findings. Additionally, we conducted pathogenicity evaluations and demonstrated the ability of this fungus to colonize roots of ultradwarf bermudagrass (Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davey), its native host, via ectotrophic, dark runner hyphae, causing disease symptoms including root discoloration and reduced root and shoot mass. Altogether, our discoveries enabled recognition and description of a new species, Gaeumannomyces nanograminis, associated with rotted roots of ultradwarf bermudagrass.

Additions to the knowledge of hydnoid Steccherinaceae: Cabalodontia, Etheirodon, Metuloidea, and Steccherinum

ABSTRACT The family Steccherinaceae includes genera with smooth, hydnoid, and poroid hymenophores, monomitic to dimitic hyphal systems, and generative hyphae with clamps or simple septa. Steccherinum is the largest genus in the family, with a worldwide distribution, and is characterized mainly by a dimitic hyphal system and presence of thick-walled encrusted cystidia. Species traditionally included in Steccherinum, however, have been transferred to other genera based on results of molecular phylogenetic analyses. Even though knowledge of Steccherinaceae has increased in the past few years, very little is known about the hydnoid species of the family, especially from the Neotropics. In this study, we present morphological and phylogenetic analyses on hydnoid specimens of Steccherinaceae collected in the Neotropics. Molecular data of nuc internal transcribed spacer region ITS1-5.8S-ITS rDNA (ITS) and portions of nuc 28S rDNA (28S), translation elongation factor 1-α (tef1), and the largest subunit of RNA polymerase II (rpb1) were obtained from Brazilian collections. Types and original collections were studied for morphological comparison. Samples we studied grouped in four different genera of Steccherinaceae: Cabalodontia, Etheirodon, Metuloidea, and Steccherinum. Three new neotropical species, Cabalodontia delicata, Etheirodon purpureum, and Steccherinum larssonii, are described. In addition, the new combinations Cabalodontia albofibrillosa and Metuloidea reniformis are proposed. The four genera presented in this study are compared and discussed in detail.

Multilocus phylogenies reveal three new truffle-like taxa and the traces of interspecific hybridization in Octaviania (Boletaceae, Boletales)

ABSTRACTAmong many convergently evolved sequestrate fungal genera in Boletaceae (Boletales, Basidiomycota), the genus Octaviania is the most diverse. We recently collected many specimens of Octaviania subg. Octaviania, including several undescribed taxa, from Japan and the Americas. Here we describe two new species in subgenus Octaviania, O. tenuipes and O. tomentosa, from temperate to subtropical evergreen Fagaceae forests in Japan based on morphological observation and robust multilocus phylogenetic analyses (nrDNA ITS and partial large subunit [LSU], translation elongation factor 1-α gene [TEF1] and the largest subunit of RNA polymerase II gene [RPB1]). Based on specimens from the Americas as well as studies of the holotype, we also taxonomically re-evaluate O. asterosperma var. potteri. Our analysis suggests that O. asterosperma var. potteri is a distinct taxon within the subgenus Octaviania so we recognize this as O. potteri stat. nov. We unexpectedly collected O. potteri specimens from geographically widespread sites in the USA, Japan and Colombia. This is the first verified report of Octaviania from the South American continent. Our molecular analyses also revealed that the RPB1 sequence of one O. tenuipes specimen was identical to that of a closely related species, O. japonimontana, and that one O. potteri specimen from Minnesota had an RPB1 sequence of an unknown species of O. subg. Octaviania. Additionally, one O. japonimontana specimen had an unusually divergent TEF1 sequence. Gene-tree comparison and phylogenetic network analysis of the multilocus dataset suggest that these heterogenous sequences are most likely the result of previous inter- and intra-specific hybridization. We hypothesize that frequent hybridization events in Octaviania may have promoted the high genetic and species diversity found within the genus.

A phylogenetic overview of the Hydnaceae (Cantharellales, Basidiomycota) with new taxa from China.

The family Hydnaceae (Cantharellales, Basidiomycota) is a group of fungi found worldwide which exhibit stichic nuclear division. The group is highly diverse in morphology, ecology, and phylogeny, and includes some edible species which are popular all over the world. Traditionally, Hydnaceae together with Cantharellaceae, Clavulinaceae and Sistotremataceae are four families in the Cantharellales. The four families were combined and redefined as “Hydnaceae”, however, a comprehensive phylogeny based on multiple-marker dataset for the entire Hydnaceae sensu stricto is still lacking and the delimitation is also unclear. We inferred Maximum Likelihood and Bayesian phylogenies for the family Hydnaceae from the data of five DNA regions: the large subunit of nuclear ribosomal RNA gene (nLSU), the internal transcribed spacer regions (ITS), the mitochondrial small subunit rDNA gene (mtSSU), the second largest subunit of RNA polymerase II (RPB2) and the translation elongation factor 1-alpha gene (TEF1). We also produced three more phylogenetic trees for Cantharellus based on 5.8S, nLSU, mtSSU, RPB2 and TEF1, Craterellus and Hydnum both based on the combined nLSU and ITS. This study has reproduced the status of Hydnaceae in the order Cantharellales, and phylogenetically confirmed seventeen genera in Hydnaceae. Twenty nine new taxa or synonyms are described, revealed, proposed, or reported, including eight new subgenera (Cantharellus subgenus Magnus, Craterellus subgenus Cariosi, subg. Craterellus, subg. Imperforati, subg. Lamelles, subg. Longibasidiosi, subg. Ovoidei, and Hydnum subgenus Brevispina); seventeen new species (Ca. laevihymeninus, Ca. magnus, Ca. subminor, Cr. badiogriseus, Cr. croceialbus, Cr. macrosporus, Cr. squamatus, H. brevispinum, H. flabellatum, H. flavidocanum, H. longibasidium, H. pallidocroceum, H. pallidomarginatum, H. sphaericum, H. tangerinum, H. tenuistipitum and H. ventricosum); two synonyms (Ca. anzutake and Ca. tuberculosporus as Ca. yunnanensis), and two newly recorded species (H. albomagnum and H. minum). The distinguishing characters of the new species and subgenera as well as their allied taxa are discussed in the notes which follow them. The delimitation and diversity in morphology, ecology, and phylogeny of Hydnaceae is discussed. Notes of seventeen genera which are phylogenetically accepted in Hydnaceae by this study and a key to the genera in Hydnaceae are provided.

Morphological and genetic diversification of Russula floriformis, sp. nov., along the Isthmus of Panama

ABSTRACT Species of Russula are ubiquitous members of ectomycorrhizal fungal communities in tropical ecosystems. However, an important part of the total tropical diversity of this genus and its biogeographic patterns is unknown due to the lack of studies on Russula in tropical ecosystems. We combined molecular, morphological, ecological, and biogeographic data to elaborate concepts for two new subspecies of R. floriformis (subsection Substriatinae). Russula floriformis subsp. floriformis and R. floriformis subsp. symphoniae are described as new from montane forest dominated by Quercus and/or Oreomunnea (Fagales) from Colombia and Panama, respectively. Phylogenies were constructed using nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS), D1–D2 domains of nuc 28S rDNA (28S), and partial regions of the second largest subunit of RNA polymerase II (rpb2) and translation elongation factor 1-alpha (tef1). Similar environmental conditions, similar morphology, and an ITS sequence similarity higher than 99% with only three different positions indicate that these two subspecies are closely related. Detailed observations of microscopic structures and analyses of further DNA loci, however, revealed morphological and molecular characteristics that allow distinguishing the two subspecies of R. floriformis. Spatial distribution and phylogenetic proximity of the two Russula subspecies and their ectomycorrhizal hosts, i.e., species of Quercus, suggest that their diversification is a result of comigration, adaptation, and geographic isolation along the Isthmus of Panama during the Pliocene and Pleistocene.

Neocosmospora spp. associated with dry root rot of citrus in South Africa

Citrus is one of the most important fruit crops cultivated in South Africa. Internationally, citrus dry root rot is a common disease in major citrus production areas. Several abiotic and biotic factors are involved in disease development, in which Neocosmospora species are important biotic agents. The diversity of Neocosmospora species associated with dry root rot symptoms of Citrus trees cultivated in South Africa was evaluated using morphological and molecular analyses. Multi-locus analysis was conducted, based on fragments of seven loci including: ATP citrate lyase (acl1), calmodulin (cal), internal transcribed spacer region of the rRNA (ITS), large subunit of the rRNA (LSU), RNA polymerase largest subunit (rpb1), RNA polymerase second largest subunit (rpb2), and translation elongation factor 1-alpha (tef1). A total of 62 strains representing 11 Neocosmospora species were isolated from crowns, trunks and roots of citrus trees affected by dry root rot, as well as from soils sampled in affected citrus orchards. The most commonly isolated taxa were N. citricola, N. ferruginea and N. solani, while rarely encountered taxa included N. brevis, N. crassa, N. hypothenemi and N. noneumartii. Furthermore, four Neocosmospora species are also newly described, namely N. addoensis, N. citricola, N. gamtoosensis and N. lerouxii.

Desarmillaria caespitosa, a North American vicariant of D. tabescens

ABSTRACT Desarmillaria caespitosa, a North American vicariant species of European D. tabescens, is redescribed in detail based on recent collections from the USA and Mexico. This species is characterized by morphological features and multilocus phylogenetic analyses using portions of nuc rDNA 28S (28S), translation elongation factor 1-alpha (tef1), the second largest subunit of RNA polymerase II (rpb2), actin (act), and glyceraldehyde-3-phosphate dehydrogenase (gpd). A neotype of D. caespitosa is designated here. Morphological and genetic differences between D. caespitosa and D. tabescens were identified. Morphologically, D. caespitosa differs from D. tabescens by having wider basidiospores, narrower cheilocystidia, which are often irregular or mixed (regular, irregular, or coralloid), and narrower caulocystidia. Phylogenetic analyses of five independent gene regions show that D. caespitosa and D. tabescens are separated by nodes with strong support. The new combination, D. caespitosa, is proposed.

MALDI-TOF mass spectrometry–based identification of Eurotiales from different substrates and locations in Brazil

We used matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) fingerprinting to identify 95 strains of Aspergillus, Penicillium, and Talaromyces isolated from soil, marine sediment, and plants in Brazil. Samples for mass spectrometry were composed of conidia and conidiophores directly applied to the target plate and co-crystallized with the matrix solution. Cluster analyses of MS data and phylogenetic analyses based on the second largest subunit of RNA polymerase II gene sequence (RPB2) supported the identification of 42 species in Aspergillus (n = 17), Penicillium (n = 16), and Talaromyces (n = 9). In few cases, MALDI-TOF dendrograms split strains from one species into two neighboring clusters, but strains from different species were never grouped together. Three Penicillium species delimited by MALDI-TOF MS did not correspond to known species present in the large RPB2 dataset available for this group and may represent new taxa. These results expand the scope of applications of MALDI-TOF MS to the task of screening phylogenetically diverse assemblages of morphologically similar strains derived from field collections, allowing for fast discrimination of common and rare species, and detection of possible new taxa.

Neofusicoccum caryigenum, a new species causing leaf dieback disease of pecan (Carya illinoinensis)

ABSTRACT Neofusicoccum species are endophytes and pathogens of woody hosts and members of the Botryosphaeriaceae. Leaf dieback is a new disease resulting in death of compound leaves and extensive defoliation of pecan trees (Carya illinoinensis) throughout the southeastern United States. Currently, the disease is consistently most severe on trees that are not managed with fungicides for pecan scab. Preliminary observations of the fungus isolated from symptomatic leaves indicated that it was a member of the genus Neofusicoccum. Our objectives were to confirm that this is the causal organism of leaf dieback disease of pecan and to determine whether this disease is caused by a new or previously described species of Neofusicoccum. Morphological observations of pure cultures, conidiomata, conidiogenous cells, and conidia were consistent with members of the genus Neofusicoccum. Using Koch’s postulates, we established that Neofusicoccum sp. isolated from symptomatic leaves caused the disease. We sequenced the internal transcribed spacer of the rDNA (ITS), elongation factor 1-α (EF1-α), the second largest subunit of RNA polymerase II (RPB2), and β-tubulin (TUB2) of 11 isolates collected from Georgia and Texas. Phylogenetic and network analyses of these sequences combined with publicly available sequences of 40 members of the N. parvum–N. ribis species complex and the outgroup N. australe revealed that this fungus is a member of the species complex but is genetically distinct from previously described species. We determined that leaf dieback of pecan is caused by a novel species, named herein N. caryigenum.