Fusarium verticillioides and Sarocladium zeae naturally co-inhabit maize kernels and compete to maintain their ecological niches. As either an endophyte or a pathogen, F. verticillioides is a prolific fumonisin producer and a threat to food safety. As a protective endophyte of maize, S. zeae produces the antimicrobials, pyrrocidines A and B, which have been previously described to inhibit F. verticillioides fumonisin biosynthesis, and act synergistically through two pyrrocidine-induced, molecular targets – FvZBD1 (FVEG_00314) and FvABC3 (FVEG_11089) – to inhibit growth. We used transcriptomics and challenge assays coupled with analytical chemistry techniques to investigate the mechanisms of pyrrocidine-based growth and fumonisin inhibition in F. verticillioides – with the goal of preliminarily evaluating pyrrocidine as a bio-based fumonisin inhibitor for commercial maize production. Our data show that the F. verticillioides wild-type FvZBD1 rapidly transforms pyrrocidine A into pyrrocidine B, supporting the hypothesis that FvZBD1p is a core enzyme in the pyrrocidine detoxification pathway. Transcriptomic data provide evidence that pyrrocidine does not induce the expression of F. verticillioides mycotoxins or other secondary metabolites of concern. Further, we provide the first report that combined pyrrocidine A and B repress genes of the fusaric acid, bikaverin, and fusarubin biosynthetic clusters. Intriguingly, transcriptomic results also suggest that pyrrocidines may disrupt energy metabolism by shunting the tricarboxylic acid cycle and impairing the electron transport chain. This work provides promising results on pyrrocidines as fumonisin biosynthesis inhibitors and further clarifies the role of pyrrocidines and FvZBD1 in S. zeae-F. verticillioides biocontrol interactions.
An archeological discovery, a well-preserved ancient monoxyle dated from the first century BCE to the first century CE and a fifteenth- to seventeenth-century shipwreck, excavated at the Drmno open-pit coal mine, created a unique opportunity for the fungal-induced deterioration of newly excavated archaeological wooden artifacts to be studied in Serbia for the first time. The monoxyle was carved from a single tree trunk of Pinus nigra or Pinus sylvestris, while two shipwreck wooden samples were shown to be Castanea sativa and Quercus (White Oaks group). Despite identical semihypogean conditions favorable for fungal colonization, the artifacts responded differently: the monoxyle showed extensive decay, predominantly by the brown rot fungus Coniophora puteana, with additional symptoms linked to Mortierellaceae and Niesslia sp., while the shipwreck lacked visible damage, although microscopic evidence revealed Niesslia, Cephalotrichum, and other fungi. Based on the documented fungal structures, both objects have, to an extent, shared a deteriogenic mycobiome. Most of the fungi documented on monoxyle and shipwreck are associated with soft rot, or are often linked with decayed wood. Likewise, many observed species are known to be associated with archeological wooden artifacts and to produce an array of lignocellulolytic enzymes, while the up-to-date published literature suggests that this is the first report of soft rot fungi Microascus melanosporus and Pseudogymnoascus sp. being documented on archeological wood. Understanding the site-specific fungal communities and the environmental conditions to which the objects are exposed, and identifying the wood species of artifacts, are crucial, as this information directly informs the selection of appropriate and effective conservation techniques, ensuring the long-term preservation of invaluable wooden artifacts.
Thymus satureioides is a native plant of the Moroccan Atlas Mountains and is valued for its culinary, medicinal, and cosmetic uses. The increasing pressure on its populations and its vegetation calls for sustainable farming. Arbuscular mycorrhizal fungi (AMF) are among the beneficial microbes that promote growth, phytochemicals, and bioactive properties. The role and interactions of AMF have been studied in several medicinal plants, but their specific influence on T. satureioides, including its biochemical composition, oil profile, antioxidant, and antimicrobial activities, has largely been overlooked. This study investigated how AMF influence the biochemical composition, oil profile, antioxidant activity, and antimicrobial activity of T. satureioides. The results showed that mycorrhizal inoculation significantly improved the biochemical composition of T. satureioides. Protein (1.16 vs. 0.82 mg mL-1), carbohydrate (89.26 vs. 68.51 mg mL-1), and lipid (0.82 vs. 0.64 mg mL-1) contents were higher in mycorrhizal seedlings. Secondary metabolites were also enhanced, with polyphenols (85.75 vs. 67 GAE/g EO) and flavonoids (94.44 vs. 71.11 mg Rutin/g DW) showing marked increases. GC-MS analysis revealed enrichment of key bioactive compounds, including thymol, carvacrol, and rosmarinic acid. Essential oils from AMF-inoculated seedlings exhibited stronger antioxidant activity and greater antimicrobial efficacy, with larger inhibition zones against all tested strains. The enhancement of primary and secondary metabolites in AMF-inoculated plantlets suggests that AMF symbiosis improves nutrient uptake and metabolic pathways involved in the biosynthesis of bioactive compounds. The increased levels of phenolic compounds and terpenoids explain the higher antioxidant and antimicrobial activities observed in the EOs. These findings demonstrate that AMF inoculation can act as an effective biostimulant, enhancing the plant nutritional and bioactive properties of thyme. Mycorrhizal inoculation boosts growth, mineral nutrition, biochemical profile, essential oils, and biological activities of T. satureioides. This eco-friendly mycorrhizal approach may contribute to the sustainable cultivation and valorization of Thymus satureioides, a North African endemic species, while promoting the production of high-value phytoproducts and supporting the conservation of its natural genetic resources.
BackgroundStarmerella magnoliae (formerly Candida magnoliae) is a rare yeast in clinical practice, sporadically associated with neonatal bloodstream infections, tenosynovitis in immunocompetent individuals, and infections in oncology patients. Its role in female genital tract infections is exceptionally uncommon.Presentation of caseWe describe a 42-year-old Brazilian woman presenting with genital pruritus and burning. Serological tests for HIV, hepatitis B and C, syphilis, and HPV RT-PCR were negative. Vaginal samples were cultured, identified using the Vitek 2 system (bioMérieux, France), and confirmed by MALDI-TOF MS. Antifungal resistance–associated genes were investigated by polymerase chain reaction.Culture identified S. magnoliae. Metabolic profiling demonstrated assimilation of raffinose, proline, mannose, sorbitol, nitrate, gluconate, and gentiobiose. Molecular analysis detected ERG11 and CDR2 genes associated with antifungal resistance. Empirical oral fluconazole therapy failed to achieve clinical improvement. However, intravaginal nystatin administered for 21 days resulted in complete symptom resolution and negative direct microscopy.ConclusionThis case underscores S. magnoliae as a rare cause of vulvovaginal infection, associated with azole resistance markers and poor response to fluconazole. Accurate identification using advanced microbiological and molecular methods is essential to guide appropriate therapy in uncommon infections.
IntroductionAflatoxin and other toxic fungal metabolites continue to be an issue in global agriculture. Although effective pre-harvest strategies exist and are in active use, their effectiveness can wane during storage. Therefore, processors seek viable post-harvest strategies that protect commodities from aflatoxin contamination. Recent discoveries from this lab suggest the potential for metabolite production to be a mechanism contributing to the efficacy of A. flavus biocontrol strains, whereby their secretion of soluble or volatile metabolites reduce growth and/or mycotoxin production in aflatoxigenic strains from Louisiana. Volatile metabolites from effective biocontrol strains hold potential for use as biofumigants in storage and/or transport; however, their broad-spectrum applicability must first be assessed. MethodsIn this study, we exposed twelve Aspergillus strains (nine of which were aflatoxigenic) originally sampled from regions outside of Louisiana to same four volatile organic compounds (VOCs) that were inhibitory to the Louisiana strains. The goal here was to see if these compounds would exhibit consistent control over aflatoxin producing strains no matter where they originated. ResultsLike observed for the Louisiana strains, trans-2-methyl-2-butenal more noticeably reduced growth of all strains than the other three VOCs (2,3-dihydrofuran, 3-octanone, decane). However, there were notable differences in how some strains responded to each VOC treatment regarding aflatoxin production. Strain responses to VOC treatment were variable, at times dependent on the strain, the compound, or the volume/concentration used for treatment. DiscussionAlthough, our findings supported previous findings that VOC-mediated inhibition of aflatoxin producing fungi is possible and confirmed there are multiple compounds with great potential to exploit as biofumigants, it was determined that no compound tested thus far offers blanket control and that the most effective VOC used for biofumigation may be region dependent.
