Pseudocercospora lythracearum is a widely distributed foliar pathogen of Lagerstroemia species, causing Cercospora leaf spot. It was first described from the United States. However, although the nucleotide sequences of the internal transcribed spacer (ITS) region, actin (actA) and translation-elongation factor (tef1) genes retrieved from two isolates of Ps. lythracearum were publicly available in GenBank, the sequence data from the original type specimen and other Pseudocercospora spp. found on Lagerstroemia spp. are lacking, making its molecular comparison difficult. Consequently, the taxonomic circumscription of the fungus has relied largely on morphology. In this study, we aimed to clarify molecular-phylogeny of the fungus within the genus Pseudocercospora, including samples obtained from L. indica in Korea and Japan, L. subcostata in Japan, and L. fauriei in Korea. A multilocus phylogenetic analysis was conducted using a combined dataset of ITS, actA, tef1, and the second-largest subunit of DNA-directed RNA polymerase II (rpb2) sequences. Comparative analyses with Pseudocercospora species associated with Lagerstroemia further supported the identification of our isolates as Ps. lythracearum. Multilocus analyses consistently placed all isolates in a well-supported clade together with previously identified Ps. lythracearum isolates from Korea (CBS 131925) and Japan (MUCC 890). This study represents the taxonomic clarification of Ps. lythracearum, and the first morphologically and molecularly confirmed occurrence of Ps. lythracearum on L. fauriei in Korea.
Podosphaera carpesiicola is currently regarded as endemic to Japan, despite powdery mildews on Carpesium species in Korea were previously reported under the name Sphaerotheca fusca. In the present study, 23 herbarium specimens of Carpesium-associated powdery mildews collected from various localities in Korea were examined. Both morphological (holomorph) characteristics and molecular phylogenetic analyses based on the combined internal transcribed spacer regions (ITS1 and ITS2) and large subunit gene (LSU) rDNA sequences support the identification of all specimens as P. carpesiicola. Our results provide the first confirmed record of P. carpesiicola in Korea under its currently accepted name and demonstrate its occurrence on four Carpesium species, including C. abrotanoides and C. cernuum, as newly identified hosts in Korea. These findings extend the known geographic distribution of P. carpesiicola in East Asia and clarify the taxonomic identity of earlier records previously assigned to S. fusca.
Clarifying the phylogenetic positions of microorganisms is a primary area of expertise of microbial culture collection centers. In the present study, we aimed to elucidate the phylogenetic position of a fungal strain, previously reported from a human toenail. The earlier report was able to resolve its phylogeny only until genus level (Elsinoë). After being deposited in KACC as strain KACC 410304, a comprehensive examination was conducted which included studying its morphological features as well as sequences of the internal transcribed spacer (ITS), large subunit (LSU), partial translation elongation factor 1-alpha (TEF1-α) and partial DNA-directed RNA polymerase II second LSU (RPB2) to resolve its taxonomic position. Morphological and microscopic observations indicated colonies to be slow-growing, grayish sepia on potato dextrose agar, apricot to brown color on malt extract agar and produce enteroblastic, monophialidic, hyaline, smooth to verruculose, ampulliform to doliiform conidiogenous cells. Conidia were hyaline, granular, aseptate, guttulate, ellipsoid to oblong, apex obtuse, and club shaped. Maximum-likelihood phylogenetic tree based on the combined four nuclear markers (ITS, LSU, TEF1-α, and RPB2) revealed that the strain grouped within the order Myriangiales and formed an independent lineage. Therefore, we propose that the strain does not fall under family Myriangiaceae or Elsinoaceae, but separates into a distinct clade within the order Myriangiales. We describe here Cerebroclavomyces unguium gen nov. et sp. nov. as incertae sedis within Myriangiales using KACC 410304 as its ex-type culture.
Mycoviruses can induce phenotypic and physiological changes in their fungal hosts, making them valuable biological resources. To harness this potential, it is crucial to gather comprehensive information on their distribution patterns, genomic and structural characteristics, and interactions with host fungi. In this study, we screened 64 ascomycete isolates collected from various soil environments in Korea to detect the presence of double-stranded RNA (dsRNA) elements. We identified dsRNA bands in three of these isolates. Among them, we determined the complete genome sequence of a bipartite dsRNA virus found in Cladosporium anthropophilum. Phylogenetic analyses based on the RNA-dependent RNA polymerase (RdRP) and capsid protein (CP) sequences indicated that this virus belongs to the genus Gammapartitivirus within the family Partitiviridae. Comparative sequence analyses suggested that this virus is best classified as a new isolate of Cladosporium cladosporioides partitivirus 1, which we designated as Cladosporium cladosporioides partitivirus 1 isolate IPBL11 (CcPV1-IPBL11).
Natural products have provided most of our modern pharmacopeia, serving as active molecules or scaffolds for active molecules. Their use in drug development is often inspired by their traditional or historical medical use. For many decades, this discovery pipeline has focused on identifying a single molecule responsible for much of the biological activity of a "raw" natural product preparation (e.g., a whole-plant extract) and scoping this molecule for clinical potential. However, it is increasingly realized that historical/traditional remedies with significant biological activity may owe this activity to the combined action of multiple molecules. Concomitantly, microbiologists increasingly argue that effectively fighting antimicrobial-resistant infections will rely on combination therapies that combine multiple antimicrobials and/or adjuvant molecules. We previously reconstructed a complex historical remedy, Bald's eyesalve. Our reconstruction of this remedy had strong antibiofilm activity, which relied on the presence of multiple ingredients. Here, we report that Bald's eyesalve has multiple antibacterial effects on exemplar gram-positive (Staphylococcus aureus) and gram-negative (Acinetobacter baumannii) pathogens. Bald's eyesalve disrupts bacterial membrane integrity; inhibits the expression of genes associated with bacterial adhesins, virulence factors, and efflux pumps in both S. aureus and A. baumannii; inhibits quorum sensing in S. aureus; and causes the downregulation of genes involved in de novo nucleotide biosynthesis in S. aureus. Finally, we show that this multifaceted mechanism of action makes it difficult for S. aureus, A. baumannii, and Pseudomonas aeruginosa to evolve resistance against Bald's eyesalve. Bald's eyesalve could be used to identify a defined cocktail of natural products suitable for preclinical testing as a multi-target antibacterial preparation to which resistance may arise more slowly than current single-molecule antibiotics.IMPORTANCEThe increasing mortality and economic cost of antimicrobial resistance (AMR) have made it one of the biggest threats to global health. Available antibiotics are in short supply due to the slow progress in the discovery of new antibiotics. Hence, there is a need for alternative treatment options against difficult-to-treat infections. We have identified a natural product cocktail based on a historical remedy with broad-spectrum antibacterial activity and a multifaceted mechanism of action. We have shown that there is slower resistance evolution to this cocktail compared to mainline antibiotics, and it could be used as the foundation of an alternative treatment to antibiotics in clinical settings.
