Background: Peanut (Arachis hypogaea), a vital oil and food crop globally, is susceptible to web blotch which is a significant foliar disease caused by Phoma arachidicola Marasas Pauer&Boerema leading to substantial yield losses in peanut production. Calcium treatment has been found to enhance plant resistance against pathogens. Results: This study investigates the impact of exogenous calcium on peanut resistance to web blotch and explores its mechanisms. Greenhouse experiments revealed that exogenous calcium treatment effectively enhanced resistance to peanut web blotch. Specifically, amino acid calcium and sugar alcohol calcium solutions demonstrated the best induced resistance effects, achieving reduction rates of 61.54% and 60% in Baisha1016, and 53.94% and 50% in Luhua11, respectively. All exogenous calcium treatments reduced malondialdehyde (MDA) and relative electrical conductivity (REC) levels in peanut leaves, mitigating pathogen-induced cell membrane damage. Exogenous calcium supplementation led to elevated hydrogen peroxide (H₂O₂) content and superoxide anion (O₂^∙-) production in peanut leaves, facilitating the accumulation of reactive oxygen species (ROS) crucial for plant defense responses. Amino acid calcium and sugar alcohol calcium treatments significantly boosted activities of peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) in peanut leaves. Activation of these antioxidant enzymes effectively scavenged excess ROS, maintaining ROS balance and mitigating cellular damage. Conclusions: In summary, exogenous calcium treatment triggered ROS production, which was subsequently eliminated by the activation of antioxidant enzymes, thereby reducing cell membrane damage and inducing defense responses against peanut web blotch.

Aconitum kusnezoffii is a perennial medicinal plant belong to the Ranunculaceae family and distributed mainly in Northeast and North China. In July of 2018, a typical southern blight disease of A. kusnezoffii was observed in commercial fields of Qingyuan County, Fushun City, Liaoning Province, China. The fungus mainly infected stem base and tuberous roots of the plant by wrapping the hyphae and absorbing nutrition, resulting in tuberous root wilted or whole plant death. Morphological characteristics of colony and sclerotia of three representative strains isolated from the diseased plants differed obviously from those of Sclerotium rolfsii isolated from A. carmichaeli. Sclerotia were large (0.8-5.1 mm size), reddish-brown, irregular and pitted surfaces, and the hyphae was white, compact or fluffy, with a growth rate ranging from 8.0 mm/d to 10.1 mm/d. Phylogenetic analysis of the internal transcribed spacer and the large subunit sequences showed that three strains isolated from A. kusnezoffii formed a unique and well supported clade that groups with the reference isolates of S. delphinii. Based on phylogentic analysis, cultural and morphological characteristics, the three isolates of A. kusnezoffii were identified as S. delphinii. The optimum temperature for mycelial growth of the three tested isolates were 30℃ and sclerotia formed and matured more easily at 20℃. Light promoted the growth of mycelial, while dark was beneficial to the formation and maturation of sclerotia. The pathogenicity of S. delphinii showed stronger than S. rolfsii at low temperature (20℃). This is the first report of S. delphinii causing southern blight on A. kusnezoffii in China and this finding would provide a basis for disease accurate diagnosis and the development of effective management strategies.

Light regulation is critical in fungal growth, development, morphogenesis, secondary metabolism, and the biological clock. The fungus Elsinoë arachidis is known to produce the mycotoxin Elsinochrome (ESC), a key factor contributing to its pathogenicity, under light conditions. Although previous studies have predominantly focused on the light-induced production of ESC and its biosynthetic pathways, the detailed mechanisms underlying this process remain largely unexplored. This study explores the influence of light on ESC production and gene expression in E. arachidis. Under white light exposure for 28 days, the ESC yield was observed to reach 33.22 nmol/plug. Through transcriptome analysis, 5925 genes were identified as differentially expressed between dark and white light conditions, highlighting the significant impact of light on gene expression. Bioinformatics identified specific light-regulated genes, including eight photoreceptor genes, five global regulatory factors, and a cluster of 12 genes directly involved in the ESC biosynthesis, with expression trends confirmed by RT-qPCR. In conclusion, the study reveals the substantial alteration in gene expression associated with ESC biosynthesis under white light and identifies potential candidates for in-depth functional analysis. These findings advance understanding of ESC biosynthesis regulation and suggest new strategies for fungal pathogenicity control.

Rainfall, particularly in continental climates with a monsoonal tendency, impacts the microbial niches during the growth of mountain cultivated ginseng. With shifts in the microbial community, diseases in ginseng cultivated and protected under rain shelter conditions may ultimately be altered. Such cultivation may influence microflora dynamics through variations in meteorological parameters; however, this is not yet clear. The present study found that rain shelter cultivation affected the distribution of fungal communities within mountain cultivated ginseng. This led to an improved community structure in the ginseng rhizosphere, characterized by the proliferation of antagonistic fungi and a reduction in pathogenic fungi. A correlation analysis of meteorological factors found that soil temperature and humidity were the primary meteorological factors affecting mountain cultivated ginseng. It is evident that rain shelter cultivation regulated the microecological environment of the mountain cultivated ginseng’s rhizosphere and resulted in positive outcomes. A disease investigation supported this finding. The incidence of ginseng root diseases, such as rust and root rot, was reduced by 5–6%. The incidence of ginseng leaf diseases, including gray mold and black spot, was reduced by 5–10%. This research provides evidence to address the dynamics of microbial ecology under rain shelter cultivation and its benefits for sustainable mountain cultivated ginseng management.

The filamentous fungus Elsinoë arachidis is a major foliar pathogen responsible for peanut scab, which is a significant disease affecting commercial peanut cultivation. Elsinochrome (ESC), produced by numerous phytopathogenic Elsinoë species, is a non-host-selective polyketide phytotoxin with strong photosensitive activity and plays a crucial role in pathogenesis on host plants. In E. arachidis, a dual-domain enzyme encoded by the gene ESCB3, containing both O-methyltransferase and a FAD-dependent monooxygenase domain, has been identified. To elucidate the role of ESCB3, the biological function, expression pattern of the ESC biosynthesis gene cluster, and associated metabolomics analyses were investigated in the present study. An ESCB3 deletion mutant (Δ ESCB3) was created by targeted gene disruption. Notably, ESC production was completely blocked in the Δ ESCB3 mutant, and the expression of ESC biosynthetic genes, except for the polyketide synthase gene ESCB1, was significantly downregulated. Additionally, the Δ ESCB3 exhibited heightened sensitivity to multiple stress tolerance compared with the wild type, especially oxidative stress/H ₂ O ₂ , highlighting the crucial role of ESCB3 in growth, development, and ESC biosynthesis in E. arachidis. Pathogenicity assays revealed a significant reduction in the pathogenicity of the Δ ESCB3 mutant, suggesting a possible correlation with the suppressed biosynthesis of ESC. Metabolomic analyses further confirmed that ESCB3 is indispensable for the ESC biosynthetic process and acts as a key regulatory factor. Collectively, the results of this study provide significant insights into the molecular mechanisms governing ESCB3-mediated virulence and ESC production in E. arachidis, offering potential targets for disease control strategies in peanut scab. [ ] Copyright © 2026 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Mycocentrospora acerina is responsible for inducing severe leaf blight on Asarum heterotropoides. However, its poor sporulation under standard culture conditions significantly limits research on pathogenicity and disease management. This study aimed to develop an efficient high-yield and reproducible sporulation protocol by optimizing cultural conditions and nutritional factors. The results indicate that near-ultraviolet (Near-UV) light serves as a critical inducer of sporulation for M. acerina. In contrast to the standard culture on PDA medium at 20℃, where the pathogen fails to produce conidia, exposure to Near-UV light effectively stimulated sporulation, yielding a relatively robust production of 1.37×10³ conidia/mL after 21 days. Furthermore, V8 medium provided the optimal substrate conditions, yielding 4.56×10³ conidia/mL under the same cultural conditions after 14 days, a value significantly higher than those on other tested media. The optimized protocol (Near-UV light, V8 medium, 20℃, pH 7.0, 1 g/L glucose, and 1 g/L potassium nitrate) achieved a conidial yield of 1.0×10⁵ conidia/mL after 14 days. The conidia produced using the optimized sporulation protocol were morphologically identical to wild-type conidia and exhibited similar germination and pathogenicity. This established sporulation protocol provides vital materials for further studies, including infection, pathogenicity mechanism, and host-pathogen interaction dynamics and lays a theoretical basis for developing targeted strategies to control A. heterotropoides leaf blight.