Crown rot is an important postharvest disease of banana and is frequently associated with species of the Fusarium fujikuroi species complex (FFSC). This study investigated the diversity, pathogenicity, and fumonisin biosynthetic gene profiles of FFSC isolates associated with banana crown rot in the Cariri region, Ceará, northeastern Brazil. Among the 151 Fusarium isolates recovered, 64 were assigned to the FFSC based on tef1-α and RPB2 sequence analyses. Five species were identified: F. annulatum, F. joanfreemaniae, F. musae, F. pseudocircinatum, and F. verticillioides. Thirty-five isolates caused lesions on wounded banana fruits, with marked variation in aggressiveness. Fusarium musae was the most frequent and generally the most aggressive species, whereas all F. verticillioides isolates were non-pathogenic under the conditions tested. PCR screening detected FUM1 and/or FUM8 markers in 28 isolates, including pathogenic and non-pathogenic isolates, while no amplicons were detected in F. joanfreemaniae. These findings expand current knowledge of FFSC diversity associated with banana crown rot in Brazil and reveal substantial inter- and intraspecific variation in pathogenicity, aggressiveness, and fumonisin biosynthetic gene profiles, highlighting the need to assess pathogenicity and potential toxigenic risk independently.
Objective: To investigate the prophylactic efficacy of monoclonal antibody (mAb) 1D2 against Aspergillus fumigatus in an immunosuppressed mouse model of invasive aspergillosis (IA). Methods: BALB/c mice (n = 18) were immunosuppressed with cyclophosphamide and randomly assigned into three groups (n = 6 each): 1D2 prophylaxis, isotype antibody (6B10) control and PBS control. Two hours prior to intravenous inoculation of A. fumigatus conidia (2 × 105 conidia per mouse), 1D2 (100 μg) or control interventions were administered intravenously. Clinical signs and body weight were monitored, and mice were euthanised for tissue and blood collection 48 h after infection. Liver injury was assessed histologically using a modified semi-quantitative scoring system. Fungal burden was assessed by colony-forming unit (CFU) counts in blood and sampled liver, spleen, kidney, and lung tissues. Plasma cytokine concentrations were analysed by ELISA. Results: 1D2-treated mice showed a lower loss of body weight post-inoculation than PBS controls (p = 0.007) and had significantly reduced clinical distress scores on days 1 and 2 (p < 0.05). Histopathological analysis showed alleviated liver injury in the 1D2 group, with a median liver injury score of 4.5 (IQR 3.0–5.25) versus 8.0 (IQR 6.75–10.0) in PBS controls (p < 0.05). CFU counts in the liver, spleen and kidney were significantly lower in the 1D2-treated group than in either control group (p < 0.05). Plasma IL-6 levels were reduced in the 1D2-treated group (582.9 ± 279.7 pg/mL) compared with PBS (1073 ± 289.1 pg/mL) and 6B10 (1080 ± 357.4 pg/mL)-treated controls (p < 0.05). TNF-α and IL-1 showed no significant differences. Conclusions: Prophylactic administration of mAb 1D2 was associated with reduced post-inoculation weight loss, lower clinical distress scores, less liver injury, and reduced recoverable CFU counts in sampled liver, spleen and kidney tissues. Plasma IL-6 concentrations were also lower in the 1D2-treated group. These findings provide proof-of-concept evidence supporting further preclinical evaluation of 1D2 as a prophylactic candidate against IA.
Thelephora ganbajun is a highly valued edible ectomycorrhizal fungus, but the relationships between its natural distribution and growth and soil environmental conditions remain poorly understood. In this study, mycosphere soils and adjacent control soils were collected from seven geographic sites in Yunnan Province, China. Soil physicochemical properties, enzyme activities, untargeted metabolomics, and bacterial and fungal amplicon sequencing were integrated to characterize geographic variation in the belowground environment and its associations with fruiting-body metabolic phenotypes. Nutrient levels and enzyme activities differed between mycosphere and control soils, and the magnitude of these differences varied among sites. A total of 5006 metabolites were annotated, including 77 differential metabolites shared across all seven sites, although their directions of change were strongly site-dependent. Bacterial and fungal communities in mycosphere soils exhibited significant geographic differentiation. The first two axes of distance-based redundancy analysis cumulatively explained 50.04% and 56.73% of the variation in bacterial and fungal communities, respectively. Soil pH, alkali-hydrolyzable nitrogen, and available phosphorus emerged as key environmental factors, with the latter two significantly associated with both bacterial and fungal community structure. Procrustes analysis further revealed concordant geographic differentiation of the two microbial communities. The volatile, non-volatile, and free amino acid metabolic phenotypes of fruiting bodies were associated with different components of the belowground environment. These findings reveal geographic variation in the belowground environment of T. ganbajun during a single fruiting season and its associations with fruiting-body metabolic phenotypes, providing candidate environmental indicators for future habitat assessment.
Candida auris is a multidrug-resistant fungal pathogen for which echinocandins are recommended first-line therapy, yet its adaptive responses to this drug class remain incompletely understood. This study defined the genome-wide transcriptional responses of C. auris strain B11244 (Clade IV) to subinhibitory caspofungin, micafungin, and anidulafungin and examined whether shared responses corresponded to cell-wall remodeling. Growth-based broth microdilution indicated susceptibility to all three drugs by MIC (caspofungin, approximately 0.5–1 µg/mL; micafungin, 0.125 µg/mL; anidulafungin, approximately 0.03125 µg/mL), but caspofungin uniquely produced marked paradoxical growth at 4–8 µg/mL, consistent with caspofungin tolerance. RNA sequencing identified 2920, 2130, and 2149 differentially expressed genes following caspofungin, micafungin, and anidulafungin exposure, respectively, including 283 co-upregulated and 157 co-downregulated genes. All three drugs induced a conserved cell-wall integrity program marked by transcriptional induction of Bck1-Mkc1 and Hog1 MAPK pathway components and an 18-gene signature involved in chitin synthesis and cell-wall cross-linking. The response was strongest with caspofungin, and RT-qPCR corroborated representative transcriptional changes. No canonical FKS1 hotspot mutation was detected; an I1572L substitution was predicted to be structurally neutral. Calcofluor White microscopy showed qualitatively enhanced peripheral fluorescence following each treatment, whereas colorimetric glucosamine measurement demonstrated significantly increased bulk chitin only with caspofungin (149% of control); micafungin (120%) and anidulafungin (98%) did not differ significantly from control. Taken together, these findings are consistent with inducible, MAPK-associated cell-wall remodeling as a potential FKS1-independent contributor to echinocandin tolerance, while showing that transcriptional convergence does not imply uniform phenotypic outcomes.
Temperature limits jiaobai (Zizania latifolia) production by its symbiont, the smut fungus Ustilago esculenta, yet the cellular mechanisms underlying this thermal sensitivity remain poorly understood. In this study, we combined controlled temperature regimes, transmission electron microscopy, and RNA sequencing to dissect the fungal response to heat. A moderate 30/25 °C day/night regime was associated with the highest proportion of cells containing multivesicular bodies (MVBs; 65.0%) and the only detectable autophagosome-like structures (6.7%), whereas regimes incorporating 35 °C drove extensive vacuolar degradation and cytoplasmic rarefaction. Strikingly, the strongest MVB accumulation occurred with the fewest transcriptional changes among 126 endocytic, autophagic, and vacuolar genes, suggesting as a working hypothesis that temperature may primarily shape MVB homeostasis through post-transcriptional, flux-level regulation rather than wholesale transcriptional reprogramming. However, low numbers of MVB-related differentially expressed genes (DEGs) were not unique to the 30/25 °C regime: AT35/25 also had only eight MVB-related DEGs yet showed severe degradation, and T35 had numerous MVBs with only 14 MVB-related DEGs. These observations indicate that DEG counts alone cannot predict MVB abundance. The 30/25 °C regime, which qualitatively resembled the field phenotype, induced only 418 differentially expressed genes, whereas harsher regimes triggered broader transcriptional responses without corresponding increases in MVB abundance. These findings provide a cellular and transcriptional framework for understanding the heat sensitivity of jiaobai production, highlighting the importance of diurnal thermal rhythms and post-transcriptional regulation in fungal thermal acclimation.
