Culturable gut microbiota of marine wood boring invertebrates Dicyathifer manni (wright, 1866), Sphaeroma terebrans (Bate, 1866) and Cirolana sp.

Abstract

The cultured aerobic copiotrophic bacteria and fungi from the digestive tracts of Dicyathifer manni (Wright, 1866), Sphaeroma terebrans (Bate, 1866) and a Cirolana sp. were investigated. The objective of the present study was to determine the bacterial and fungal diversity within the digestive tracts of the woodborers. Bacteria isolated on nutrient agar and fungi isolated on sabouraud dextrose agar (SDA) were identified by 16S rRNA and ITS gene barcoding respectively, with subsequent phylogenetic analysis. Four strains of bacteria, namely Lysinibacillus boronitolerans (from D. manni and S. terebrans), Lysinibacillus fusiformis (from S. terebrans and Cirolana sp.), Lysinibacillus sphaericus and Lysinibacillus xylanilyticus (both from Cirolana sp.) had similarity to known 16S rRNA sequences of 98–99%. A neighbor-joining phylogenetic tree based on 16S rRNA gene sequences showed that the bacteria are closely related members of the genus Lysinibacillus. Different strains of Ascomycetes fungi were also isolated. Aspergillus niger was isolated from the digestive tracts of D.manni and S. terebrans. In addition, Neosartorya fischeri, A. fumigatus and Penicillium sp. were isolated from D. manni whereas Botryotinia fuckeliana was isolated form S. terebrans digestive tract. A. costaricaensis and A. fumigatus were isolated from Cirolanna sp. digestive tract. The fungi had similarity to known ITS sequences of 95–100%. Existence of bacterial and fungal groupings symbiotically associated with woodborers gut is proposed. Investigation of the functional characteristics and role in the host organism is required to confirm the symbiotic status of the microorganisms associated with the woodborers digestive tract.