Polydomus karssenii gen. nov. sp. nov. is a dark septate endophyte with a bifunctional lifestyle parasitising eggs of plant parasitic cyst nematodes (Heterodera spp.)

Macaw palm is a harbor of new non-grass species of dark septate endophytes belonging to the genus Pseudophialophora (Magnaporthaceae)

Macaw palm (Acrocomia aculeata) is an oleaginous crop native to Brazil with significant economic and environmental value. It has been explored commercially in Brazil within sustainable management. The microbiota associated with macaw palm is still little known and there is no report about their root's fungal endophytes. Recently, the community of dark septate endophytes (DSE) from macaw palm began to be investigated, and new taxa were found. The present study aimed to describe two new Pseudophialophora species associated with macaw palm roots. The isolation method performed was the dilution-to-extinction cultivation. ITS, RPB1, tef1-α, LSU, and SSU regions were amplified and sequenced for phylogenetic analyses. The isolates formed two phylogenetically independent lineages and we proposed the new species P. chlamydospora and P. endophytica. For the first time, new taxa of DSE fungi were described from macaw palm.

Melanized root-associated fungi: key players in plant-soil systems

Melanized root-associated fungi are a group of fungi that produce melanized structures and form root associations, including different mycorrhizal and endophytic symbioses with plants. They are pervasive across terrestrial ecosystems and play an important role in the prevailing soil carbon (C) and nutrient cycling syndromes through direct and indirect mechanisms, where they may strongly modulate plant-microbe interactions and structure root and soil microbiomes. Furthermore, melanized root-associated fungi can confer on plants an enhanced ability to tolerate abiotic and biotic stressors such as drought, extreme temperatures, heavy metals, and pathogen attacks. We propose that melanized root-associated fungi are a cohesive and ecologically relevant grouping that can be an indicator of plant-soil system functioning, and considering them will advance research on plant-soil interactions.

Rhexocercosporidium matricariae sp. nov.: A New Pathogen on the Medicinal Plant Matricaria recutita

A new disease was observed on chamomile plants (Matricaria recutita) in various commercially cultivated fields in 2016 and 2017 in Germany. From symptomatic stems and leaves, the fungal species described here was isolated repeatedly. Koch's postulates using in planta experiments were fulfilled by inoculation of chamomile plants proving the fungus to be the causal agent of the disease. Morphological studies and phylogenetic analyses using internal transcribed spacer, large subunit, and translation elongation factor-1α sequences suggested that the fungus represents a new species within the genus Rhexocercosporidium (Helotiales). The data are presented together with a description of the growth parameters and comprehensive illustrations of the new species, Rhexocercosporidium matricariae. All species so far assigned to Rhexocercosporidium are compared and discussed. The combination Rhexocercosporidium microsporum is validated.

Laburnicolamine: A Rare Penillic Acid Congener from the Nematode Cyst-Associated Fungus Laburnicola nematophila

A chemical investigation of a methanol extract derived from a solid-state rice culture of the nematode-cyst associated fungus Laburnicola nematophila K01 led to the isolation and characterization of a previously undescribed penillic acid analogue named laburnicolamine (1). The chemical structure was elucidated through comprehensive 1D and 2D NMR spectroscopic analyses in methanol-d4 and DMSO-d6, alongside with HR-ESI-MS spectrometry. The absolute configuration of 1 was concluded through the electronic circular dichroism (ECD) and time-dependent density functional theory-ECD (TDDFT-ECD) computations compared to its acquired spectrum. Biological assays revealed that compound 1 exhibited no significant cytotoxic, antimicrobial, or nematicidal activity.

Dactylfungins and Tetralones: Bioactive Metabolites from a Nematode-Associated Laburnicola nematophila

A chemical investigation of Laburnicola nematophila, isolated from cysts of the plant parasitic nematode Heterodera filipjevi, affored three dactylfungin derivatives (1-3) and three tetralone congeners (4-6). Dactylfungin C (1), laburnicolin (4), and laburnicolenone (5) are previously undescribed natural products. Chemical structures of the isolated compounds were determined based on 1D and 2D NMR spectroscopic analyses together with HR-ESI-MS spectrometry and comparison with data reported in the literature. The relative configurations of compounds 1, 2, and 4-6 were determined based on their ROESY data and analysis of their coupling constants (J values). The absolute configurations of 4-6 were determined through the comparison of their measured and calculated TDDFT-ECD spectra. Compounds 1-3 were active against azole-resistant Aspergillus fumigatus.

Laburnicotides A-F: Acyclic N-Acetyl Oligopeptides from the Nematode-Cyst-Associated Fungus Laburnicola nematophila

Nematode-associated fungi revealed the potential to produce a broad spectrum of chemical scaffolds. In this study, a mycelial extract of Laburnicola nematophila, a fungal strain derived from the cereal cyst nematode Heterodera filipjevi, was chemically explored and afforded six unprecedentedly reported acylic N-acetyl oligopeptides, laburnicotides A-F (1-6). Structure elucidation of the isolated compounds was established based on comprehensive 1D and 2D NMR spectroscopic analyses together with the acquired HR-ESI-MS spectrometric data. The absolute configuration of amino acid residues in 1-6 was established by performing advanced Marfey's derivatization method. All isolated compounds were assessed for their cytotoxic, antimicrobial, antiviral, and nematicidal activities with no potential activity observed.

Omnipolyphilins A and B: Chlorinated Cyclotetrapeptides and Naphtho-α-pyranones from the Plant Nematode-Derived Fungus Polyphilus sieberi

Chemical exploration for two isolates of the recently described ascomycete species Polyphilus sieberi, derived from the eggs of the plant parasitic nematode Heterodera filipjevi, afforded the identification of many compounds that belong to various metabolite families: two previously undescribed chlorinated cyclotetrapeptides, omnipolyphilins A (1) and B (2), one new pyranonaphthoquinone, ventiloquinone P (3), a 6,6'-binaphto-α-pyranone dimer, talaroderxine D (4) in addition to nine known metabolites (5-13) were isolated from this biocontrol candidate. All isolated compounds were characterized by comprehensive 1D, 2D NMR, and HR-ESI-MS analyses. The absolute configurations of the cyclotetrapeptides were determined by a combination of advanced Marfey's method, ROE correlation aided by conformational analysis, and TDDFT-ECD calculations, while ECD calculations, Mosher's method, and experimental ECD spectra were used for ventiloquinone P (3) and talaroderxine D (4). Among the isolated compounds, talaroderxine D (4) showed potent antimicrobial activities against Bacillus subtilis and Staphylococcus aureus with MIC values of 2.1 and 8.3 μg mL-1, respectively. Additionally, promising inhibitory effects on talaroderxine D (4) against the formation of S. aureus biofilms were observed up to a concentration of 0.25 μg mL-1. Moreover, ophiocordylongiiside A (10) showed activity against the free-living nematode Caenorhabditis elegans.

Exploring the Diversity and Systematics of Phaeosphaeriaceae: Taxonomic Novelties from Ecologically Diverse Habitats and Their Phylogenetic Resolution

The family Phaeosphaeriaceae is a diverse group of ascomycetous fungi that are commonly found in terrestrial habitats worldwide. In recent years, there has been increasing interest in the biodiversity of Phaeosphaeriaceae in China, particularly in Sichuan Province, which has not been fully explored for its high fungal diversity. In our study, we conducted extensive surveys in Sichuan Province to identify and describe new species of Ascomycota with diverse habitats. Here, we present a taxonomic revision of Phaeosphaeriaceae with taxonomic novelties from terrestrial habitats in Sichuan Province based on a multi-gene phylogenetic approach. Our study focuses on the description of four new species of Phaeosphaeriaceae, representing novel additions to the diversity of this fungal family. Using a combination of morphological and molecular data, we provide detailed descriptions of the new taxa and their placement within the family. Additionally, we discuss the phylogenetic relationships of these new taxa with other members of Phaeosphaeriaceae, providing insights into the correct taxonomic classification of the family. Our taxonomic revision contributes to understanding fungal diversity in China and provides a foundation for future studies investigating the taxonomy and ecological roles of Phaeosphaeriaceae fungi. Furthermore, our multi-gene phylogenetic approach provides increased resolution and accuracy in the delimitation of species boundaries within the family. Our study highlights the importance of continued exploration and taxonomic revision in order to fully understand the diversity and distribution of fungal species in China and beyond. New species:Paraloratospora sichuanensis, Phaeosphaeria chengduensis, P. sichuanensis, and Septoriella shoemakeri. New combinations:Paraloratospora breonadiae, P. fructigena, Septoriella ammophilicola, S. asparagicola, S. festucae, S. luzulae, and S. verrucispora. New names:Septoriella paradactylidis, and S. neomuriformis.