Uncovering fungal community composition in natural habitat of Ophiocordyceps sinensis using high-throughput sequencing and culture-dependent approaches.

BACKGROUND: The fungal communities inhabiting natural Ophiocordyceps sinensis play critical ecological roles in alpine meadow ecosystem, contribute to infect host insect, influence the occurrence of O. sinensis, and are repertoire of potential novel metabolites discovery. However, a comprehensive understanding of fungal communities of O. sinensis remain elusive. Therefore, the present study aimed to unravel fungal communities of natural O. sinensis using combination of high-throughput sequencing and culture-dependent approaches. RESULTS: A total of 280,519 high-quality sequences, belonging to 5 fungal phyla, 15 classes, 41 orders, 79 families, 112 genera, and 352 putative operational taxonomic units (OTUs) were obtained from natural O. sinensis using high-throughput sequencing. Among of which, 43 genera were identified in external mycelial cortices, Ophiocordyceps, Sebacinia and Archaeorhizomyces were predominant genera with the abundance of 95.86, 1.14, 0.85%, respectively. A total of 66 genera were identified from soil microhabitat, Inocybe, Archaeorhizomyces, unclassified Thelephoraceae, Tomentella, Thelephora, Sebacina, unclassified Ascomycota and unclassified fungi were predominant genera with an average abundance of 53.32, 8.69, 8.12, 8.12, 7.21, 4.6, 3.08 and 3.05%, respectively. The fungal communities in external mycelial cortices were significantly distinct from soil microhabitat. Meanwhile, seven types of culture media were used to isolate culturable fungi at 16 °C, resulted in 77 fungal strains identified by rDNA ITS sequence analysis, belonging to 33 genera, including Ophiocordyceps, Trichoderma, Cytospora, Truncatella, Dactylonectria, Isaria, Cephalosporium, Fusarium, Cosmospora and Paecilomyces, etc.. Among all culturable fungi, Mortierella and Trichoderma were predominant genera. CONCLUSIONS: The significantly differences and overlap in fungal community structure between two approaches highlight that the integration of high-throughput sequencing and culture-dependent approaches would generate more information. Our result reveal a comprehensive understanding of fungal community structure of natural O. sinensis, provide new insight into O. sinensis associated fungi, and support that microbiota of natural O. sinensis is an untapped source for novel bioactive metabolites discovery.

[Development of sensitive-micro RF coils in desktop MRI systems].

A RF coil (or probe) is one of the key components in NMR spectrometers and MRI systems, and designing a quality RF coil is a cheaper way to improves the signal-to-noise ratio (SNR) of systems and image quality. According to different applications there are a variety of RF coils. This article describes high-sensitive micro RF coils used in NMR spectrometers specially for test-tube samples. Their performance has been verified on the desktop MRI systems.