Project description:Many bivalve species produce groups of strong proteinaceous byssal threads to rigidly attach to underwater substrates. Fibres like these have potential applications as biomedical materials due to their unique mechanical characteristics. The byssus and byssal thread producing glands of Pinctada maxima have not yet been characterised. RNA was isolated from P. maxima foot and byssal stem region tissues and sequenced using the Illumina platform. A de novo reference transcriptome comprising 34,281 contiguous sequences was assembled, and tissue replicates were mapped against the reference for quantitative analysis. Tryptic digests of byssal threads were analysed by LC-MS/MS. The resultant peptides were matched to 62 protein sequences derived from our reference transcriptome. Components of the byssus were identified for further characterisation, including a highly expressed perlucin-like foot protein (Pmfp1) and a recently identified protein that we refer to herein as glycine-rich thread (GRT) protein. This work provides principal knowledge on the molecular components of the byssus for P. maxima and the foot ultrastructure involved in the creation of byssal threads. This study advances our knowledge of byssus biosynthesis in non-mytilids, providing a platform for the design of new marine biopolymers.