The Amazonian catfish, Panaque nigrolineatus have several physiological adaptions enabling the scraping and consumption of wood (xylivory), facilitating a detritivorous dietary strategy. Composed of lignocellulose, wood is a difficult substrate to degrade and as yet, it is unclear whether the fish obtains any direct nutritional benefits from wood ingestion and degradation. However, there are numerous systems that rely on microbial symbioses to provide energy and other nutritional benefits for host organisms via lignocellulose decomposition. While previous studies on the microbial community of P. nigrolineatus have focused upon the bacterial population, the role of fungi in lignocellulose degradation in the fish has not yet been examined. This study describes the detection of fungi within the fish gastrointestinal tract. Using next generation sequencing, the effects of diet on enteric fungal populations were examined in each gastrointestinal tract region. Fungal species were found to vary in different regions of the gastrointestinal tract as a function of diet. This study is the first to examine the fungal community in a xylivorous fish and results support the hypothesis that diet influences fungal distribution and diversity within the gastrointestinal tract of P. nigrolineatus.

Background: Plants are critical to global environmental health and food production strategies; most plants utilise flowers as part of their reproduction cycle. Flowers attract pollinators using a range of complex strategies and floral nectar is an essential component of this attraction profile. Nectar is a nutrient rich liquid, containing a range of sugars, organic acids, amino acids, lipids and vitamins, found to be a suitable habitat for a wide range of fungi, but so far, limited bacterial diversity has been detected. Several antimicrobial properties and adverse environmental conditions, such as high osmotic pressure present in the nectar were thought to reduce bacterial numbers.Results: This study reports the next generation sequencing analysis of the bacterial and fungal diversity in flower nectar. This was achieved in four floral species native to the United Kingdom (Lamium album, white dead nettle; Narcissus pseudonarcissus, daffodil, Hyacinthoides non-scripta, English bluebell and Digitalis purpurea, the common foxglove). All flower species examined had a diverse bacterial and fungal populations present with a core microbiome detected, dominated by Proteobacteria and Firmicutes phyla, while Basidomycota were the most persistent fungal phyla in all of the floral nectar types sampled. However, many unique bacterial and fungal species were detected at lower abundances. Furthermore, in N. pseudonarcissus and D. purpurea floral nectar, the microbial diversity detected in the nectar between flowers exposed to the environment versus non-environment exposed flowers, was different.Conclusions: These results suggest that floral nectars in different plant species do contain a distinct microbiome and the individual flower microbial community diversity may be affected by floral nectar composition, insect visitation and other environmental factors.