Tingfu Zhang

Aspergillus westerdijkiae, a filamentous fungus commonly isolated from pickled vegetables and high-salt condiments, can cause spoilage and produce nephrotoxic ochratoxin A (OTA) under saline conditions. However, its adaptive mechanisms to salt stress remain unclear. To address this, the pickle-derived strain NDX1 was subjected to 0, 1.0, 1.5, and 2.0 mol/L NaCl treatments. Colony growth was assessed after 7 days of incubation on PDA plates supplemented with the respective NaCl concentrations. For physiological indices, mycelia were pre-cultured in salt-free PDB for 5 days, followed by the addition of NaCl to final concentrations (0, 1.0, 1.5, and 2.0 mol/L) and further incubation for 2 days, after which relative electrical conductivity (REC) and malondialdehyde (MDA) content were measured. Colony diameters were recorded to evaluate vegetative growth; REC was determined by conductometry to assess cell membrane permeability; and MDA content was measured via the thiobarbituric acid (TBA) colorimetric method to indicate lipid peroxidation levels. Transcriptome sequencing combined with qRT-PCR validation was employed to identify differentially expressed genes (DEGs) involved in osmotic adaptation. Results showed that low salinity (1.0 mol/L NaCl) promoted growth, while higher concentrations (≥1.5 mol/L NaCl) inhibited it, accompanied by increased REC and decreased MDA, forming a distinctive high-permeability, low-lipid-peroxidation phenotype. A total of 3155 DEGs were detected, mainly associated with the HOG-MAPK cascade, glycerol biosynthesis, and ion transport pathways. Eight key HOG-MAPK genes and 21 glycerol metabolic genes were upregulated in a concentration-dependent manner, with the terminal kinase Hog1 coordinating transcription of downstream effectors governing glycerol synthesis and ion homeostasis. These findings demonstrate that A. westerdijkiae integrates de novo glycerol production and intracellular lipid remodeling via the HOG-MAPK pathway to achieve osmotic adaptation under hypersaline stress. This work identifies potential molecular targets for controlling toxigenic spoilage caused by this species in high-salt fermented foods.

Penicillium astrolabium is a primary pathogenic fungus that causes grape blue mold during postharvest, leading to substantial losses in the grape industry. Nevertheless, hypovirulence-associated mycoviruses can attenuate the virulence of postharvest grape-rot pathogens, thereby offering a promising biocontrol tool. Characterizing the mycovirus repertoire of P. astrolabium is imperative for grape protection, yet remains largely unexplored. Here, we screened six strains harboring viruses in 13 P. astrolabium isolates from rotted grapes. Using high-throughput sequencing, four novel dsRNA viruses and two +ssRNA viruses were identified from the six P. astrolabium strains. The dsRNA viruses belonged to two families—Chrysoviridae and Partitiviridae—and were designated to Penicillium astrolabium chrysovirus 1 (PaCV1), Penicillum astrolabium partitivirus 1′ (PaPV1′), Penicillum astrolabium partitivirus 2 (PaPV2), and Penicillum astrolabium partitivirus 3 (PaPV3). For the +ssRNA viruses, one was clustered into the Alphaflexiviridae family, while the other one was clustered into the Narnaviridae family. The two +ssRNA viruses were named Penicillium astrolabium alphaflexivirus 1 (PaAFV1) and Penicillium astrolabium narnavirus 1 (PaNV1), respectively. Moreover, several viral genomic contigs with non-overlapping and discontinuous sequences were identified in this study, which were probably representatives of five viruses from four families, including Discoviridae, Peribunyaviridae, Botourmiaviridae, and Picobirnaviridae. Taken together, our findings could expand the diversity of mycoviruses, advance the understanding of mycovirus evolution in P. astrolabium, and provide both potential biocontrol resources and a research system for dissecting virus–fungus–plant interactions.

Sunflower (Helianthus annuus L.) is a major oilseed crop in the world, but recently it has become a popular ornamental flower in China (Kaya ET AL., 2012). Notably, stem rot was frequently observed...

Sterol 14α-demethylases from Cytochrome P450 family (CYP51s) are essential enzymes in sterol biosynthesis and well-known as the target of antifungal drugs. The 3D structure of CYP51A from Penicillium italicum (PiCYP51A) was constructed through homology modeling based on the crystal structure of human CYP51A (PDB: 3LD6). Molecular dynamics (MD) simulation was operated to relax the initial model and followed by quality assessment using PROCHECK program. On the basis of the docking information on the currently available CYP51s with the patent demethylase inhibitors (DMIs), pharmacophore-based virtual screening combined with docking analysis was performed to pick out twelve new compounds from ZINC database. Six hits revealed in the ligand database suggested potential ability to inhibit PiCYP51A. Compared to patent fungicide triazolone, the top three lead compounds had similar or higher affinity with the target enzyme, and accordingly, exhibited comparable or lower EC₅₀ values to P. italicum isolates. The results could provide references for de novo antifungal drug design.