Molecular phylogeny and morphology reveal three novel species of Curvularia (Pleosporales, Pleosporaceae) associated with cereal crops and weedy grass hosts

Morphological and molecular characterization of Curvularia species from Iran, with description of two novel species and two new records

Curvularia species exhibit a wide range of ecological roles, including plant, animal, or human pathogens, as well as epiphytes, saprophytes, or endophytes, predominantly associated with cultivated cereals. In this study, several fungal isolates with similar characteristics in the genus Curvularia were recovered from various poaceous hosts (Poales plants) in different locations in Iran during 2012‒2022. Based on the morphological characteristics and multilocus phylogeny of the translation elongation factor-1 alpha (TEF1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and the internal transcribed spacer (ITS-rDNA) genes, the studied isolates were assigned to five species, of which Curvularia caspica, sp. nov. and C. cyperi, sp. nov. are introduced as novel species and Curvularia nodulosa and C. oryzae are new records for Iran's mycobiota. Molecular studies revealed a closer relationship between one of the studied species (Curvularia sp.) and C. frankliniae. However, due to the absence of detailed morphological characteristics for C. frankliniae, morphological comparisons were not feasible. To precisely establish their phylogenetic position, more isolates need to be analyzed. Consequently, the studied species was identified as Curvularia sp. in this study. Additionally, a new clade, "papendorfii," was established to accommodate 11 species that share common morphological characteristics and form a distinct clade in phylogenetic analyses. The morphology, habitat, distribution, and evolutionary relationships of each species with other Curvularia species were analyzed, accompanied by detailed illustrations and descriptions. This comprehensive study offers valuable insights into the diversity and distribution of Curvularia species, enhancing our understanding of fungal ecology and taxonomy.

Evaluation of two MALDI-TOF MS systems and extraction methods for identification of filamentous fungi recovered from clinical specimens

Rapid and accurate identification of cultured molds is important to determine clinical significance and therapeutic decision-making. Conventional mold identification uses phenotypic macroscopic and microscopic characterization; however, this can take days or weeks for colony maturity and definitive microscopic structure formation, be limited to genus-level identification, and be misidentified due to morphologic mimics or similarities between closely related species. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) revolutionized bacterial and yeast identification but remains uncommon for molds in part because of limited reference libraries. Here, a retrospective 5-year review at a large teaching hospital found that 88.6% of identified molds were in the Bruker Filamentous Fungi Library 3.0 and 91.5% in the VITEK Knowledge Base Library 3.2.0. A prospective evaluation was also performed on early growth from 205 consecutive, working clinical isolates. Each mold was processed using the VITEK chemical extraction method and modified NIH chemical plus bead-beating extraction method; both extractions were tested on both systems. When compared to conventional identification, more molds were identified using VITEK extractions over NIH extractions using the VITEK (65 and 59%) and Bruker (56 and 54%) systems, respectively, using the ≥1.5 log Bruker threshold. VITEK MS identified more molds, regardless of the extraction method. Isolates without consensus agreement (n = 116) underwent sequence-based identification, which demonstrated that conventional identification had the highest genus-level (84%) but lowest species-level (3%) identification rates compared to VITEK (59 and 52%, respectively) and Bruker (52 and 36%) using VITEK extractions. Taken together, our findings suggest both MALDI-TOF systems can supplement conventional mold identification to optimize identification rates with species-level distinction.

IMPORTANCE

Mold identification using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) remains uncommon in clinical laboratories. Contributing concerns include limited genus/species spectra in the MALDI-TOF MS libraries, varying success rates in the literature regarding extraction methods and instrumentation, and the lack of practical performance evaluations using early mold colony growth, which would be used in a clinical mycology laboratory. This study used multiple approaches to improve our understanding of the clinical utility and performance of MALDI-TOF MS mold identification.

Identification, characterization, and sensitivity to phytochemicals of a novel Curvularia species associated with leaf spot disease on Curcuma kwangsiensis

A leaf spot disease affecting Curcuma kwangsiensis (Zingiberaceae) has been observed in Qinzhou City, Guangxi Province. Infected leaves exhibit yellow-brown spots that progressively expand and eventually lead to leaf death. Curvularia isolates were obtained from the diseased leaves with tissue isolation and single spore purification methods. To accurately identify these isolates, we analyzed their morphological characteristics and phylogenetic relationships using combinations of ITS, GAPDH, and EF-1α gene sequences. Phylogenetic analysis showed that the investigated strains formed a distinct clade separate from other recognized Curvularia species. Furthermore, the strains exhibited differences in conidiophore size and conidia shape/size. Based on phylogenetic studies, morphology, and pathogenicity tests, the pathogen was identified as a new species named Curvularia qinzhouensis. Optimal conditions for mycelial growth were observed at 30 °C and pH 8. The sensitivity of the pathogen to various phytochemicals was also examined. Honokiol, thymol, and citral demonstrated effective antifungal effects, with EC50 values of 6.72 ± 1.75, 25.74 ± 4.30, and 54.24 ± 4.69 µg/ml, respectively. The present investigation provides the first report of leaf spot disease on C. kwangsiensis caused by C. qinzhouensis, and valuable insights for the prevention and control of this disease.

Diversity of Pleosporalean Fungi Isolated from Rice (Oryza sativa L.) in Northern Thailand and Descriptions of Five New Species

Pleosporales represents the largest order within the class Dothideomycetes (Fungi), comprising phytopathogenic, saprobic, and endophytic taxa with a widespread presence in terrestrial and aquatic environments. Rice (Oryza sativa) is a primary economic crop in numerous tropical countries, particularly in Thailand. Studying fungal species associated with rice holds the potential to enhance our understanding of fungal diversity, lifestyles, and biology of rice, offering valuable insights for future research aimed at disease management and yield improvement. Thirty-nine pleosporalean isolates were obtained from various parts of rice plants collected across diverse regions in Chiang Rai Province, Thailand. Species identification involved a combination of morphology and molecular phylogeny, utilizing multi-locus sequence analyses of the ITS, LSU, SSU, gapdh, rpb2, tef1, and tub2 genes. The isolates were identified in 18 taxa distributed across five families and ten genera, including five new species (Bipolaris chiangraiensis, Ophiosphaerella oryzae, Paraphaeosphaeria oryzae, Pyrenochaetopsis oryzicola, and Setophoma oryzicola). Additionally, six new host records and two new geographical records are documented. Photoplates, detailed morphological descriptions, and phylogenetic trees are provided to elucidate the placement of both known and novel taxa.

Molecular phylogeny and morphology reveal two new graminicolous species, Curvularia aurantiasp. nov. and C. vidyodayana sp. nov. with new records of Curvularia spp. from Sri Lanka

Despite being a small island, Sri Lanka is rich in fungal diversity. Most of the fungi from Sri Lanka have been identified as pathogens of vegetables, fruits, and plantation crops to date. The pleosporalean genus Curvularia (Dothideomycetes) includes phytopathogenic, saprobic, endophytic, and human/animal opportunistic pathogenic fungal species. The majority of the plant-associated Curvularia species are known from poaceous hosts. During the current study, 22 geographical locations of the country were explored and collections were made from 10 different poaceous hosts. Morphology and molecular phylogeny based on three loci, including nuclear internal transcribed spacers 1 and 2 with 5.8S nrDNA (ITS), glyceraldehyde-3-phosphate dehydrogenase (gapdh), and translation elongation factor 1-α (tef1) supported the description of two new species of fungi described herein as C. aurantia sp. nov. and C. vidyodayana sp. nov. Moreover, novel host-fungal association records for C. chiangmaiensis, C. falsilunata, C. lonarensis, C. plantarum, and C. pseudobrachyspora are updated herein. In addition, five species within the genus Curvularia, viz., C. asiatica, C. geniculata, C. lunata, C. muehlenbeckiae, and C. verruculosa represent new records of fungi from Sri Lanka. Citation: Ferdinandez HS, Manamgoda DS, Udayanga D, Munasinghe MS, Castlebury LA (2023). Molecular phylogeny and morphology reveal two new graminicolous species, Curvularia aurantia sp. nov. and C. vidyodayana sp. nov. with new records of Curvularia spp. from Sri Lanka. Fungal Systematics and Evolution 12: 219-246. doi: 10.3114/fuse.2023.12.11.

The morphoanatomy of Serjania erecta Radlk (Sapindaceae) provides evidence of biotrophic interactions by endophytic fungi within leaves

Background

The leaves of Serjania erecta Radlk (Sapindaceae) are renowned in ethnobotany for their medicinal properties and are significant as a medicinal resource for traditional Brazilian communities. As necrotic spots are common on these leaves, indicating interaction with phytopathogenic fungi, it was hypothesized that biotrophic fungal species colonize the leaf tissues of S. erecta.

Methods

To test this hypothesis, we employed standard techniques in plant anatomy, which enabled us to investigate the interaction of fungal structures with plant tissues and describe the morphoanatomical and histochemical characteristics of the epidermis and limbus of S. erecta.

Results

The anatomical analysis showed the existence of leaf teeth on the leaf tips. Additionally, hyphae, conidiospores, and spores of Bipolaris/Curvularia species were detected on the adaxial epidermis. Moreover, melanized microsclerotia were found in glandular areas of the leaf teeth and the phloem, providing evidence of biotrophic behavior. The hypothesis that biotrophic phytopathogenic fungi interact with S. erecta leaf tissues was confirmed, despite the presence of many bioactive compounds (such as flavonoids, alkaloids, and essential oils), as evidenced by histochemical analyses. The presence of tector, glandular, and scabiform trichomes on the leaf teeth and epidermis was also revealed. This study presents, for the first time, the synthesis of essential oils and alkaloids in the leaves of S. erecta. Additionally, it investigates previously unexplained aspects of the anatomy and histochemistry of the species, as well as its interaction with resident microorganisms. Therefore, it is recommended that future research focus on extracting and characterizing the oils and alkaloids of S. erecta, as well as exploring other aspects related to its microbiome and its relationship.

Fungal diversity notes 1512-1610: taxonomic and phylogenetic contributions on genera and species of fungal taxa

This article is the 14th in the Fungal Diversity Notes series, wherein we report 98 taxa distributed in two phyla, seven classes, 26 orders and 50 families which are described and illustrated. Taxa in this study were collected from Australia, Brazil, Burkina Faso, Chile, China, Cyprus, Egypt, France, French Guiana, India, Indonesia, Italy, Laos, Mexico, Russia, Sri Lanka, Thailand, and Vietnam. There are 59 new taxa, 39 new hosts and new geographical distributions with one new combination. The 59 new species comprise Angustimassarina kunmingense, Asterina lopi, Asterina brigadeirensis, Bartalinia bidenticola, Bartalinia caryotae, Buellia pruinocalcarea, Coltricia insularis, Colletotrichum flexuosum, Colletotrichum thasutense, Coniochaeta caraganae, Coniothyrium yuccicola, Dematipyriforma aquatic, Dematipyriforma globispora, Dematipyriforma nilotica, Distoseptispora bambusicola, Fulvifomes jawadhuvensis, Fulvifomes malaiyanurensis, Fulvifomes thiruvannamalaiensis, Fusarium purpurea, Gerronema atrovirens, Gerronema flavum, Gerronema keralense, Gerronema kuruvense, Grammothele taiwanensis, Hongkongmyces changchunensis, Hypoxylon inaequale, Kirschsteiniothelia acutisporum, Kirschsteiniothelia crustaceum, Kirschsteiniothelia extensum, Kirschsteiniothelia septemseptatum, Kirschsteiniothelia spatiosum, Lecanora immersocalcarea, Lepiota subthailandica, Lindgomyces guizhouensis, Marthe asmius pallidoaurantiacus, Marasmius tangerinus, Neovaginatispora mangiferae, Pararamichloridium aquisubtropicum, Pestalotiopsis piraubensis, Phacidium chinaum, Phaeoisaria goiasensis, Phaeoseptum thailandicum, Pleurothecium aquisubtropicum, Pseudocercospora vernoniae, Pyrenophora verruculosa, Rhachomyces cruralis, Rhachomyces hyperommae, Rhachomyces magrinii, Rhachomyces platyprosophi, Rhizomarasmius cunninghamietorum, Skeletocutis cangshanensis, Skeletocutis subchrysella, Sporisorium anadelphiae-leptocomae, Tetraploa dashaoensis, Tomentella exiguelata, Tomentella fuscoaraneosa, Tricholomopsis lechatii, Vaginatispora flavispora and Wetmoreana blastidiocalcarea. The new combination is Torula sundara. The 39 new records on hosts and geographical distribution comprise Apiospora guiyangensis, Aplosporella artocarpi, Ascochyta medicaginicola, Astrocystis bambusicola, Athelia rolfsii, Bambusicola bambusae, Bipolaris luttrellii, Botryosphaeria dothidea, Chlorophyllum squamulosum, Colletotrichum aeschynomenes, Colletotrichum pandanicola, Coprinopsis cinerea, Corylicola italica, Curvularia alcornii, Curvularia senegalensis, Diaporthe foeniculina, Diaporthe longicolla, Diaporthe phaseolorum, Diatrypella quercina, Fusarium brachygibbosum, Helicoma aquaticum, Lepiota metulispora, Lepiota pongduadensis, Lepiota subvenenata, Melanconiella meridionalis, Monotosporella erecta, Nodulosphaeria digitalis, Palmiascoma gregariascomum, Periconia byssoides, Periconia cortaderiae, Pleopunctum ellipsoideum, Psilocybe keralensis, Scedosporium apiospermum, Scedosporium dehoogii, Scedosporium marina, Spegazzinia deightonii, Torula fici, Wiesneriomyces laurinus and Xylaria venosula. All these taxa are supported by morphological and multigene phylogenetic analyses. This article allows the researchers to publish fungal collections which are important for future studies. An updated, accurate and timely report of fungus-host and fungus-geography is important. We also provide an updated list of fungal taxa published in the previous fungal diversity notes. In this list, erroneous taxa and synonyms are marked and corrected accordingly.

Activity of Aqueous Extracts from Native Plants of the Yucatan Peninsula against Fungal Pathogens of Tomato In Vitro and from Croton chichenensis against Corynespora cassiicola on Tomato

Plant extracts are a valuable alternative to control pathogens of horticultural crops. In the present study, four species of pathogenic fungi were isolated from leaf spots on Solanum lycopersicum and identified by traditional and molecular techniques as Alternaria alternata ITC24, Corynespora cassiicola ITC23, Curvularia lunata ITC22, and Fusarium equiseti ITC32. When 11 aqueous extracts from eight native plants of the Yucatan Peninsula were tested against the four fungi in vitro, the extract from Croton chichenensis roots was most active, inhibiting mycelial growth (79-100%), sporulation (100%), and conidial germination (71-100%) at 3% (w/v). A logarithmic-diagrammatic scale of the pathosystem C. cassiicola-S. lycopersicum was established and used to assess disease severity on inoculated tomato plants in a greenhouse after treatment with the aqueous extract from C. chichenensis roots at 12% (w/v). After 21 days, the disease severity was 57% lower than on the control without extract applied. This dose of the extract was not phytotoxic to tomato leaves and was compatible with the beneficial organisms Bacillus subtilis CBCK47 and Trichodema asperellum Ta13-17. The antifungal efficacy of C. chichenensis is highly promising for incorporation into integrated disease management of tomato crops.

Morpho-Phylogenetic Evidence Reveals Novel Pleosporalean Taxa from Sichuan Province, China

Pleosporales is the largest and most morphologically diverse order in Dothideomycetes, including a large proportion of saprobic fungi. During the investigation of microfungi from decaying wood in Sichuan Province, several novel fungal taxa of asexual and sexual morphs were collected, identified, and well-described. Phylogenetic analyses based on SSU, ITS, LSU, RPB2 and TEF1α gene sequences suggested that these new taxa were related to Pleosporales and distributed in five families, viz. Amorosiaceae, Bambusicolaceae, Lophiostomataceae, Occultibambusaceae and Tetraplosphaeriaceae. The morphological comparison and molecular phylogeny evidence justify the establishment of six new taxa, namely Bambusicola guttulata sp. nov., Flabellascoma sichuanense sp. nov., Neoangustimassarina sichuanensis gen. et sp. nov., Occultibambusa sichuanensis sp. nov. and Pseudotetraploa bambusicola sp. nov. Among them, Neoangustimassarina was introduced as the second sexual morph genus in Amorosiaceae; Bambusicola guttulata, O. sichuanensis and P. bambusicola were isolated from bamboos, which contributed to the diversity of bambusicolous fungi. The detailed, illustrated descriptions and notes for each new taxon are provided, as well as a brief note for each family. The potential richness of fungal diversity in Sichuan Province is also discussed.

Pleocatenata chiangraiensis gen. et. sp. nov. (Pleosporales, Dothideomycetes) from medicinal plants in northern Thailand

Pleocatenata, a new genus, is introduced with its type species, Pleocatenatachiangraiensis, which was isolated from withered twigs of two medicinal plants, Clerodendrumquadriloculare (Blanco) Merr (Verbenaceae) and Tarennastellulata (Hook.f.) Ridl (Rubiaceae) in northern Thailand. The genus is characterized by mononematous, septate, brown or dark brown conidiophores, monotretic conidiogenous cells and catenate, obclavate, olivaceous to blackish brown conidia. Phylogenetic analysis of combined LSU, SSU, tef1-α, rpb2 and ITS sequence data showed Pleocatenata forms a distinct phylogenetic lineage in Pleosporales, Dothideomycetes. Therefore, we treat Pleocatenata as Pleosporales genera incertae sedis based on morphology and phylogenetic analyses. Descriptions and illustrations of the new taxa are provided, and it is compared with morphologically similar genera.