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Palm trees (Arecaceae) are among the most popular ornamental plants worldwide. Despite extensive research on the fungi associated with Arecaceae, the diversity and ecological dynamics of fungi affecting ornamental palms remain poorly studied, although they have significant impact on palm health and economic value. Furthermore, while research on palm fungal diversity has traditionally focused on tropical assemblages, ornamental palms in temperate climates offer a unique opportunity to explore the diversity of palm fungi in non-native habitats. The present study conducted a preliminary assessment of the diversity and ecology of potential phytopathogenic fungi associated with foliar lesions on various ornamental palm host species in Portugal, combining morphological examination, PCR-based genomic fingerprinting, and biodiversity data analysis. The examination of 134 foliar lesions sampled from 100 palm trees resulted in a collection of 2064 palm leaf spotting fungi (PLSF), representing a diverse fungal assemblage of 320 molecular operational taxonomic units (MOTUs) across 97 genera. The overall fungal community composition revealed a distinct assemblage dominated by Neosetophoma, Alternaria, Phoma, and Cladosporium, with a profusion of infrequent and rare taxa consistent with a logseries distribution. Significantly positive co-occurrence (CO) patterns among prevalent and uncommon taxa suggest potential synergistic interactions enhancing fungal colonisation, persistence, and pathogenicity. The taxonomic structures of the PLSF contrasted markedly from tropical palm fungi, especially in the prevalence of pleosporalean coelomycetes of the Didymellaceae and Phaeosphaeriaceae, including recently introduced or not previously documented genera on Arecaceae. This novel assemblage suggests that climatic constraints shape the structure of palm fungal communities, resulting in distinctive temperate and tropical assemblages. In addition, the fungal assemblages varied significantly across palm host species, with temperate-native palms hosting more diverse, coelomycete-enriched communities. The present findings highlight foliar lesions as hyperdiverse microhabitats harbouring fungal communities with intricate interactions and a complex interplay of climatic, host, and ecological factors. With climate change altering environmental conditions, the identification of fungi thriving in or inhabiting these microhabitats becomes crucial for predicting shifts in pathogen dynamics and mitigating future fungal disease outbreaks. Understanding these complex ecological dynamics is essential for identifying potential phytopathogenic threats and developing effective management strategies for the health and sustainability of ornamental plants. [ABSTRACT FROM AUTHOR]

Due to cryptic diversification, phenotypic plasticity and host associations, multilocus phylogenetic analyses have become the most important tool in accurately identifying and circumscribing species in the Diaporthe genus. However, the application of the genealogical concordance criterion has often been overlooked, ultimately leading to an exponential increase in novel Diaporthe spp. Due to the large number of species, many lineages remain poorly understood under the so-called species complexes. For this reason, a robust delimitation of the species boundaries in Diaporthe is still an ongoing challenge. Therefore, the present study aimed to resolve the species boundaries of the Diaporthe arecae species complex (DASC) by implementing an integrative taxonomic approach. The Genealogical Phylogenetic Species Recognition (GCPSR) principle revealed incongruences between the individual gene genealogies. Moreover, the Poisson Tree Processes' (PTPs) coalescent-based species delimitation models identified three well-delimited subclades represented by the species D. arecae, D. chiangmaiensis and D. smilacicola. These results evidence that all species previously described in the D. arecae subclade are conspecific, which is coherent with the morphological indistinctiveness observed and the absence of reproductive isolation and barriers to gene flow. Thus, 52 Diaporthe spp. are reduced to synonymy under D. arecae. Recent population expansion and the possibility of incomplete lineage sorting suggested that the D. arecae subclade may be considered as ongoing evolving lineages under active divergence and speciation. Hence, the genetic diversity and intraspecific variability of D. arecae in the context of current global climate change and the role of D. arecae as a pathogen on palm trees and other hosts are also discussed. This study illustrates that species in Diaporthe are highly overestimated, and highlights the relevance of applying an integrative taxonomic approach to accurately circumscribe the species boundaries in the genus Diaporthe. [ABSTRACT FROM AUTHOR]

Due to cryptic diversification, phenotypic plasticity and host associations, multilocus phylogenetic analyses have become the most important tool in accurately identifying and circumscribing species in the Diaporthe genus. However, the application of the genealogical concordance criterion has often been overlooked, ultimately leading to an exponential increase in novel Diaporthe spp. Due to the large number of species, many lineages remain poorly understood under the so-called species complexes. For this reason, a robust delimitation of the species boundaries in Diaporthe is still an ongoing challenge. Therefore, the present study aimed to resolve the species boundaries of the Diaporthe arecae species complex (DASC) by implementing an integrative taxonomic approach. The Genealogical Phylogenetic Species Recognition (GCPSR) principle revealed incongruences between the individual gene genealogies. Moreover, the Poisson Tree Processes’ (PTPs) coalescent-based species delimitation models identified three well-delimited subclades represented by the species D. arecae, D. chiangmaiensis and D. smilacicola. These results evidence that all species previously described in the D. arecae subclade are conspecific, which is coherent with the morphological indistinctiveness observed and the absence of reproductive isolation and barriers to gene flow. Thus, 52 Diaporthe spp. are reduced to synonymy under D. arecae. Recent population expansion and the possibility of incomplete lineage sorting suggested that the D. arecae subclade may be considered as ongoing evolving lineages under active divergence and speciation. Hence, the genetic diversity and intraspecific variability of D. arecae in the context of current global climate change and the role of D. arecae as a pathogen on palm trees and other hosts are also discussed. This study illustrates that species in Diaporthe are highly overestimated, and highlights the relevance of applying an integrative taxonomic approach to accurately circumscribe the species boundaries in the genus Diaporthe.

ABSTRACT Thailand and other tropical regions have high fungal diversity. Our investigation and examination of microfungi on palms (Arecaceae) revealed two new ascomycetous species of Fissuroma. Fissuroma arengae and F. wallichiae spp. nov. are introduced using morphological and phylogenetic evidence. The novel species have coriaceous ascomata, cylindrical-clavate asci and ascospores with a distinct and thin mucilaginous sheath. Fissuroma arengae is similar to F. wallichiae but can be distinguished by minor morphology, host substrate and gene base-pair differences. Phylogenetic analyses of combined LSU, ITS, SSU, tef1-α and rpb2 sequence data showed that these strains grouped within Fissuroma, further confirming this genus as monophyletic. The two new species are described and illustrated to support their taxonomic placement. Fissuroma appears to be a highly diverse genus often occurring on palms. It is likely that more research will result in numerous new taxa being discovered.

The phylogenetic affinities of four representative Endocalyx taxa at the species and variety levels are studied based on materials collected on different palm hosts in Japan and the states of Hawaii and Texas, USA. They include specimens and their isolates belonging to E. cinctus, E. indumentum, E. melanoxanthus var. grossus, and E. melanoxanthus var. melanoxanthus. Phylogenetic analyses of nuclear ribosomal DNA sequence data (ITS-LSU nrDNA) confirmed that Endocalyx belongs to the order Xylariales (Sordariomycetes) where all species and varieties treated form a strongly supported monophyletic lineage within the family Cainiaceae. They were also phylogenetically well resolved and consistent with their morphological and ecological circumscription. Species status is proposed for E. melanoxanthus var. grossus under the name E. grossus comb. et stat. nov. on the basis of its distinct morphological, molecular, cultural, and ecological characteristics. The putative placement of Endocalyx within the family Apiosporaceae (Amphisphaeriales), based on the presence of basauxic conidiophores, is rejected considering that all species treated clustered within the distant Cainiaceae (Xylariales). This characteristic mode of conidiophore elongation is determined to have evolved independently within distantly related ascomycetous lineages. Novel morphological and cultural features of Endocalyx taxa based on new isolates are described and commented. The recently described E. metroxyli is reduced to a synonym with E. melanoxanthus. [ABSTRACT FROM AUTHOR]

During the course of a study of palm fungi in Portugal, several Bartilinia-like taxa were isolated. Morphological characters and phylogenetic data derived from ITS and LSU sequences supported the establishment of two new Morinia species introduced here as M. trachycarpi and M. phoenicicola spp. nov. isolated from foliar diseases of ornamental palm trees in Lisbon, Portugal. The morphological concept of Morinia is broadened to include enclosed pycnidial conidiomata and conidia with wedge-shaped apical cells, new distinctive morphological characteristics observed in M. trachycarpi. Bartalinia robillardoides was also isolated and is presented here as a new host and geographical record on foliar lesions of Phoenix reclinata from Lisbon, Portugal. Comparative morphological data on species of Morinia, as well as a key to species in Morinia, are provided and discussed. [ABSTRACT FROM AUTHOR]

Palms (Arecaceae) are substrates for a highly diverse range of fungi. Many species are known as saprobes and many are important plant pathogens. Over the course of our studies of micro-fungi from palms in Thailand, two new taxa were discovered. Morphological characteristics and phylogenetic analyses of combined ITS, LSU, SSU, and tef1-α sequence data revealed their taxonomic positions within Massarinaceae. There are currently ten genera identified and accepted in Massarinaceae, with the addition of the two new genera of Haplohelminthosporium and Helminthosporiella, that are introduced in this paper. Each new genus is provided with a full description and notes, and each new taxon is provided with an illustration for the holotype. A list of identified and accepted species of Helminthosporium with morphology, host information, locality, sequence data, and related references of Helminthosporium reported worldwide is provided based on records in Species Fungorum 2021. This work provides a micro-fungi database of Haplohelminthosporium, Helminthosporiella, and Helminthosporium which can be modified and validated as new data come to light.

Cannonia is a xylarioid genus originally described from the southern hemisphere (Argentina and Australia) growing on dead parts of palms. To date, the genus is considered monospecific and the only species recognized is C. australis. During collection trips in the State of Maranhão, Brazil, specimens of C. australis were gathered on the inflorescence rachis and floral pedicels of a Syagrus species (Arecaceae). Description and line drawings are provided, this being the first record from Brazil. [ABSTRACT FROM AUTHOR]

A study of saprotrophic microfungi associated with the palm Calamus sp. in Thai forests yielded 88 species, with 40 ascomycetes (45.5%), and 48 anamorphic taxa (54.5%) from 212 fungal collections. The most common fungi were Tetraploa sp. (14.1% of all records), Morenoina palmicola (11.8%), Circinoconis paradoxa (5.2%), Diaporthe sp. (4.7%), and Helminthosporium sp. (4.7%). The percentage of fungi occurring in dry versus damp materials were 68.5% and 31.5%, respectively, with 61% of fungi occurring on petioles and 39% on rachides. The fungi occurring on Calamus sp. are compared with those recorded on other palms in Australia, Brunei, Hong Kong and Thailand. [ABSTRACT FROM AUTHOR]

Berkleasmium crunisia sp. nov. is described from a decaying rachis of Calamus sp. (Arecaceae) from Khuan Ka Long, Satun Province, Thailand. This Berkleasmium species differs morphologically from other species in possessing subtending cells and larger conidia. The phylogenetic relationship of the genus Berkleasmium among sexual ascomycetes also was examined. Sequence analyses from 18S, 28S and ITS-5.8S rDNA were analyzed phylogenetically under maximum parsimony, Bayesian and neighbor joining criteria. Phylogenies revealed that Berkleasmium is not monophyletic. Berkleasmium micronesicum and B. nigroapicale are related to Westerdykella cylindrica and Sporormia australis, which are members of the family Sporormiaceae (Pleosporales). Other species, including our new taxon, appear to share phylogenetic affinities with other anamorphic fungi, whose classification within the Pleosporales is still obscure. Analyses of 18S, 28S, ITS (+5.8S) rDNA and combined (18S+28S) gene sequences fail to give sufficient phylogenetic resolution within the Pleosporales. [ABSTRACT FROM AUTHOR]

Three new species of Craspedodidymum, C. siamense, C. licualae, and C. microsporum, are described and illustrated based on specimens collected on decaying trunks and sheaths of the palm, Licuala longecalycata, in Sirindhorn Peat Swamp Forest, Narathiwat, Southern Thailand. They are compared with similar species, and a key to the genus is provided. [ABSTRACT FROM AUTHOR]

Unisetosphaeria penguinoides gen. et sp. nov. and three new species of Dactylaria are described from dead petioles and rhachides of the palms Eleiodoxa conferta and Nenga pumila (Arecaceae) collected in Sirindhorn Peat Swamp Forest, southern Thailand. Unisetosphaeria (Ascomycota) is compared with similar genera, and its placement at the family level is considered. The three new Dactylaria species (anamorphic fungi) are compared with similar species in the genus. [ABSTRACT FROM AUTHOR]

Palms (Arecaceae) are substrates for a highly diverse range of fungi. Many species are known as saprobes and many are important plant pathogens. Over the course of our studies of micro-fungi from palms in Thailand, two new taxa were discovered. Morphological characteristics and phylogenetic analyses of combined ITS, LSU, SSU, and tef1-α sequence data revealed their taxonomic positions within Massarinaceae. There are currently ten genera identified and accepted in Massarinaceae, with the addition of the two new genera of Haplohelminthosporium and Helminthosporiella, that are introduced in this paper. Each new genus is provided with a full description and notes, and each new taxon is provided with an illustration for the holotype. A list of identified and accepted species of Helminthosporium with morphology, host information, locality, sequence data, and related references of Helminthosporium reported worldwide is provided based on records in Species Fungorum 2021. This work provides a micro-fungi database of Haplohelminthosporium, Helminthosporiella, and Helminthosporium which can be modified and validated as new data come to light. [ABSTRACT FROM AUTHOR]