engleski

Characterization of cloacal mycobiome of wild and rehabilitated loggerhead sea turtles (Caretta caretta)

While the bacterial constituents of loggerhead turtles’ gut microbial communities/microbiota are better known, the fungal proportion, mycobiota, has not been analysed yet. Usually, in sea turtle biology, the fungi are studied in the context of pathological conditions like skin lesions, egg mortality, infections in captivity, and systemic mycotic infections. The role of fungi as commensals in wild animals relates to the hosts’ digestive and immune system and is known to be affected by habitat disturbances in land dwelling animals. Also, wild animals are unexplored ecological niches of fungal diversity with important biotechnological potential. We described the cloacal and environmental (tank water) mycobiota of turtles in rescue centers to elucidate how different factors, such as the age, size, length of stay in the recovery centre, season of capture, location and health status reflect on the composition of the gut mycobiota. The fungal communities were profiled by sequencing the ITS2 region of rRNA genes coupled with the UNITE database. Our results show that five most abundant genera were shared between cloacal and water samples. The fungal composition of the tank water was more even, with no predominant taxa. On all taxonomic levels, tank water samples did not differentiate from the gut mycobiota, indicating that the turtles were the main source of fungi in the respective enclosures. Both environmental and cloacal samples harbored predominantly the Sordariomycetes (Ascomycota) community followed by Agaricomycetes (Basidiomycota) – both known for members which grow on animal feces. Within Sordariomycetes, we observed members of Nectriaceae family and Xylariales order, usually implicated in animal health and involved in wood decay, respectively. Agaricomycetes identified to higher taxonomic categories included taxa hosting plant pathogens and saprotrophs, but none could be assigned to the species level. A novel species from the genus Ciliophora has been detected as dominant in three gut and two corresponding tank water samples, which would be the third discovered species in the genus. Neither taxa correlated with the health status of the turtle nor were any of the parameters implicated in shaping of the gut mycobiota, and it is likely that its composition is a result of an interplay of several factors. The mycobiota of turtles appears to represent a separate system unaffected by the marine fungal community.

mycobiota, sea turtles, adriatic sea

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