Aroramyces sinensis is described as new to science from subtropical region of southwestern China. Molecular and morphological characters separate this new hypogeous species from other existing taxa in the genus Aroramyces. Phylogenetic analyses based on partial nuc 28S rDNA (LSU) and translation elongation factor 1-α (tef1) sequences show that A. sinensis is closely related to A. gelatinosporus. This serves as the first report of Aroramyces from Asia. In addition, we provide a worldwide key to all recognized Aroramyces species.
Production of sterigmatocystin (ST) in Aspergillus nidulans involves the ST biosynthetic gene cluster, which has been considered to comprise 26 genes. However, functions of several genes within this cluster remain unclear. In this study, we investigated the role of the stcX gene in ST biosynthesis. As the open reading frame of stcX has been undefined, we deleted three putative genes adjacent to stcW simultaneously. Deletion of the region did not significantly impact growth rate across various growth conditions compared to the control strain. Chemical analyses revealed no significant change in ST production in the deletion strain compared to the control. Furthermore, the three transcripts were largely undetectable during ST biosynthesis, and the expression of other ST cluster genes was unaffected by the deletion. Our results suggest that these genes are not essential for ST biosynthesis in A. nidulans, indicating that the cluster should be delineated to exclude stcX.
This study describes Parasarocladium yichunense, a new species of Hypocreales isolated from leaf cradles of Reynoutria japonica, which were constructed by the weevil Euops chinensis for oviposition and fungal cultivation. Its taxonomic position within the genus Parasarocladium was determined using an integrative approach combining morphological, cultural, and multi-locus analyses based on the ITS, LSU, ACT, tef1, and tub2 regions. Phylogenetically, P. yichunense forms a well-supported, distinct monophyletic clade sister to the clades comprising P. debruynii and P. dipikae. Parasarocladium yichunense differs from its phylogenetically close relative, P. debruynii, in exhibiting slower growth on culture media, longer conidiophores (up to 120 μm), longer phialidic conidiogenous cells (2.3-40 μm), and larger conidia [3-11.8(-13.4) × 1.5-4.6 μm]. This discovery expands the known diversity of Parasarocladium and contributes to the growing documentation of fungal symbionts in leaf-rolling weevil mutualisms.
Myxomycetes are amoeboid protists primarily found in forest ecosystems. However, their inhabitation and ecology on twig litter remain poorly understood. Therefore, myxomycete species richness and diversity in a forest, canopy tree species and types, and the microenvironmental factors influencing their distribution were assessed. In a natural mid-temperate forest of western Japan, twig litter was seasonally sampled on the forest floor under nine canopy trees selected by different tree types and large, long-lived trees. Using moist chamber cultures (MCs), twigs were incubated to induce myxomycete fruiting. As a result, 60% of the 380 MCs produced fruiting bodies of 33 myxomycete taxa from 21 genera. Ordination of 18 myxomycete communities using non-metric multidimensional scaling distinguished two seasonal groups. The arrangement of the communities was significantly correlated with environmental factors, such as twig pH, soil pH, and diameter at breast height. Large, long-lived trees had characteristically distinct ecological habitats for myxomycetes on twig litter. Members of Cribrariales and Trichiales were dominant on coniferous twigs, whereas Physarales dominated evergreen twigs. This study suggests that canopy trees shape myxomycete communities as a microhabitat in a forest ecosystem, and a mid-temperate forest maintains a high species diversity of myxomycetes, making it an important biodiversity hotspot.
