Zubaida P. Patwary1,2, Min Zhao1, Tianfang Wang1, Nicholas A. Paul1 and Scott F. Cummins1
1UniSC Seaweed Research Group, University of the Sunshine Coast, Queensland, Australia
2Department of Aquaculture, Faculty of Fisheries, Hajee Mohammad Danesh Science and Technology University, Dinajpur 5200, Bangladesh
Emerging genomics for Asparagopsis taxiformis is has provided a strong foundation for in-depth molecular investigations, including proteomics. We investigated the proteome of A. taxiformis (Lineage 6 from Queensland, Australia) of both sporophyte and gametophyte (male and female) life history stages, using soluble and insoluble extraction methods followed by mass spectrometry. We identified several hundred of unique non-redundant proteins using a genome- and transcriptome-derived database. However, the transcriptome-derived proteins demonstrated numerous non-seaweed proteins such as those predicted to be of fungal origin. Given our focus on seaweed-specific proteins, we further investigated proteins identified from our own genome-derived protein database. Gene ontology analysis indicated that 19% were ion binding proteins (i.e., iron, zinc, manganese, potassium and copper), which may play a role in heavy metal bioremediation. In addition, we identified stress-related proteins (e.g. heat shock proteins and vanadium-dependent haloperoxidases) and numerous photosynthesis-related proteins (e.g. phycobilisomes, photosystem I, photosystem II and ATPase), of which, several were exclusively in female gametophytes. Finally, we identified 40 proteins that are predicted to be secretory. We report 10 newly identified rhodophyte proteins with high levels of gene expression. In summary, this overview of proteins expressed in A. taxiformis, across two different life history stages and between the sexes, highlights the potential for targeted protein purification for functional characterisation and applications as functional feed ingredients for livestock.