Mycology最新文献

The protective and growth-promoting activities of Colletrotrichum and Diaporthe endophytes on tomato plants (Lycopersicon esculentum Mill.) are underexplored. We screened 40 endophytic fungi associated with Mexican shrimp plant (Justicia brandegeana) using an in vitro dual culture assay for Fusarium oxysporum, one of the most important phytopathogens of tomato plants. The three best antagonists, Colletotrichum siamense (JB224.g1), C. siamense (JB252.g1), and Diaporthe masirevicii (JB270), were identified based on multilocus sequence analysis. They were assessed in vitro for their inhibition of F. oxysporum and phosphate solubilisation capacity, and for the production of indole acetic acid. Greenhouse experiments verified the growth-promoting effects of these endophytes and the suppression of F. oxysporum symptoms in tomato plants.   Under greenhouse conditions, the JB252.g1 and JB270 isolates showed positive results for seedling emergence speed. The radicular system depth of plants inoculated with JB270 was greater than that in uninoculated plants (27.21 vs 21.95 cm). The soil plant analysis development chlorophyll metre (SPAD) index showed statistically significant results, especially for the endophyte JB224.g1 (36.99) compared to the control plants (30.90) and plants infected solely with F. oxysporum (33.64).

Ophiocordyceps sinensis is a well-known entomogenous fungus with its fruiting bodies or cultural mycelium as food and herbal medicines in Asia. While metabolites which could responsible for its potent pharmaceutical effects has long remained to be elucidated. In this work, chemical investigation on the solid culture of O. sinensis strain LY34 led to the discovery of six digalactosyldiacylglycerols (DGDGS, 1-6) including one new. The structure of compound 1 was determined based on the comprehensive spectra analysis, including NMR, MSⁿ, IR, and chemical derivatisation. Bioactivity studies showed a weak cytotoxicity of compounds 1-6 against 293 T cell and medium anti-inflammatory activity of compounds 1 and 2 on Raw 264.7 cell. The discovery of DGDGs in O. sinensis provides new insight into the pharmacologically active substances.

3,4-Dihydroxy-2,2-dimethyl-chroman derivatives have diverse physiological properties. A polyketone (3S,4S)-3,4-Dihydroxy-6-methoxy-2,2-dimethylchromom (3S,4S-DMD) with antibacterial activity was isolated from the solid culture of rare edible fungus Panus lecomtei. However, the yield of 3S,4S-DMD in solid culture of P. lecomtei is very low and the production period are too long. In this work, efficient accumulation of 3S,4S-DMD in P. lecomtei by submerged fermentation is studied. The key fermentation factors of P. lecomtei for 3S,4S-DMD production were optimised by single-factor experiment successively, and then a Box-Behnken design (BBD) experiment was carried out to further enhance 3S,4S-DMD production. A maximum 3S,4S-DMD yield of 196.3 mg/L was obtained at 25.78 g/L glucose, 1.67 g/L MgSO₄ · 7H₂O, 40°C and 197 r/min, respectively, which increased by 1.3-fold in comparison with that in the non-optimised fermentation conditions. Furthermore, an enhanced yield of 3S,4S-DMD (261.6 mg/L) was obtained in 5-L agitated fermenter. The 3S,4S-DMD productivity in flask and fermenter reached to 7.26 and 8.07 mg/g per day, respectively, which considerably increased by over 121-fold in comparison with that in the solid fermentation (0.06 mg/g per day). This study presents a potential method for the production of 3S,4S-DMD by submerged fermentation.

The production of a distinct profile of volatile organic compounds plays a crucial role in the ecology of hypogeous Ascomycetes, and is also key to their gastronomic relevance. In this study, we explored the aroma components of two rarely investigated Chinese desert truffles, namely Mattirolomyces terfezioides and Choiromyces cerebriformis, using headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Our investigation revealed the significant presence of sulphur-containing volatiles in the aroma of M. terfezioides but not in C. cerebriformis. We discussed available information on the distribution of these interesting truffles in China and their use as choice food by local people.

Plant-based secondary metabolite production system is well established. However, host-endophyte interaction in the production of secondary metabolite is a new less exploited area that is overcoming barriers and evolving as one of the prospective fields. Endophytes such as bacteria or fungi have the ability to produce some of the secondary metabolites that mimic the plant metabolites therefore escaping the host defence system. Coumarin is one such metabolite with immense biological functions. Most of the studies have demonstrated coumarin production from fungal endophytes but not bacterial endophytes. Herein, we present an overview of all the coumarin derivatives produced from endophytic sources and their biosynthetic pathways. Furthermore, the review also throws light on the isolation of these coumarins and different derivatives with respect to their biological activity. The biotransformation of coumarin derivatives by the action of endophytic fungi is also elaborated. The present review provides an insight on the challenges faced in the coumarin production through fungal endophytes.

Rock-inhabiting fungi (RIF) constitute an ecological group associated with terrestrial rocks. This association is generally restricted to the persistent colonisation of rocks and peculiar morphological features based on melanisation and slow growth, which endow RIF with significance in eukaryotic biology, special status in ecology, and exotic potential in biotechnology. There is a need to achieve a better understanding of the hidden biodiversity, antistress biology, origin and convergent evolution of RIF, which will facilitate cultural relic preservation, exploitation of the biogeochemical cycle of rock elements and biotechnology applications. This review focuses on summarising the current knowledge of rock-inhabiting fungi, with particular reference to terminology, biodiversity and geographic distribution, origin and evolution, and stress adaptation mechanisms. We especially teased out the definition through summing up the terms related to rock-inhabting fungi, and also provided a checklist of rock-inhabiting fungal taxa recorded following updated classification schemes.

Cystoderma comprises the species with heavily universal veil remnants on basidiomes, weakly to strongly amyloid basidiospores, evanescent floccose-scaly ring zone or persistent membranous ring, which were often encountered in forests and grassland. However, they were less studied than other mushroom groups mainly because of its unclearly phylogenetic position. In this study, we gathered 16 specimens from Southwest and Northwest China, where were the richest biodiversity areas in China, and produced their ITS and nrLSU sequences. The related morphological examinations and molecular phylogenetic analysis showed they belonged to eight species, of which four were new species, and named as Cystoderma lilaceum, C. pseudoamianthinum, C. rugosolateritium, C. subglobisporum, and of which two were new records from China, and they were C. granosum, C. subvinaceum. New species and new records were described in details and discussed with other species. This study not only showed the novel geographical distributions as well as high species diversity of Cystoderma in China, but also provided more research data for the further studies in mushrooms systematics.

Magnusiomyces capitatus is an emerging opportunistic yeast, thus far mainly reported from the Western world where fungemia is the most frequent presentation in immunocompromised patients with high mortality. We described a rare case of Magnusiomyces capitatus infection from our hospital in China and reviewed six further cases published to date in Chinese literature. It is noted that half more of the cases (4/7) presented with fungemia in younger, immunosuppressed patients, whereas the remaining cases were with pneumonia in elderly, immunocompetent patients. All seven Chinese cases had favourable outcome with antifungal therapy. Based on the limited in vitro and clinical data, a combination of amphotericin B either with 5-fluorocytosine or voriconazole for fungemia in immunocompromised patients, and although fluconazole is not recommended as first-line therapy in the guideline, in our study, fluconazole alone or with 5-fluorocytosine for local pulmonary infection in immunocompetent patients is effective with good outcome.

The recently emerged fungal pathogen Candida auris often displays resistance to one or more antifungal drugs. Its infections have been identified in at least 40 countries on six continents to date. Here we report a case of C. auris candidemia in a patient in Xiamen, a city in south China. We also review currently reported cases of C. auris infection in China and compare the genetic and biological features of C. auris strains isolated from this country. Our phylogenetic analysis indicates that there are at least two C. auris genetic clades present in China (the South African clade and the south Asian clade) that display opposite mating type loci (one is MTL a and the other is MTLα). We also found that there are several distinct features among the clinical isolates studied, including the expression of virulence factors, antifungal susceptibilities, and cellular morphologies, and that these features could be associated with the mating-type of the isolate. For example, C. auris MTL a isolates generally secreted higher levels of secreted aspartyl proteases (Saps) at ambient environmental temperatures. Taken together, this study demonstrates that C. auris clinical isolates from China exhibit diversity in both biological and genetic features.