Differential protein abundance during the first month of regeneration of the Caribbean star coral Montastraea cavernosa

Abstract

It is critical to determine the methods by which coral colonies regenerate tissue lost to physical injury as they provide the physical structure of coral reef systems. To explore regeneration, circular lesions (12 mm diameter × 3 mm depth) were created in the fall of 2014 on 124 Montastraea cavernosa colonies located in the coastal waters of Grenada and Carriacou (10–12 m depth). Coral regeneration was documented at weekly intervals for 28 days. Repeated measures ANOVA on estimated weekly coral regeneration rates showed that island (p = 0.024) and colony colour (p = 0.024) were the only factors significantly affecting lesion regeneration. Mean rate of lesion closure during the first 28 days was approximately 2.8 mm2 d−1. Four identical circular lesions were created on 30 M. cavernosa colonies (Carriacou, 10–12 m depth) in the fall of 2015. One representative lesion created on each coral colony was re-sampled at each of 14, 21, and 32 or 33 days following injury, and coral tissue was flash-frozen. Tissues from 10 normally pigmented brown colonies were selected for proteomic analysis using tandem mass tags. The initial polyp sample, the day 14, and the final samples were used to quantify the difference in protein abundance as the lesions healed. In the tissue samples 6419 peptides were reliably identified, which corresponded to 906 unique proteins. During the first month of regeneration, 111 proteins were differentially abundant (p < 0.05) on at least one timepoint and of these, 11 were associated with regeneration. An additional 14 proteins were also identified that were differentially abundant (p < 0.05) and were associated with inflammation or antioxidant activity. This work demonstrates, for the first time, the differential abundance of proteins associated with regeneration in a scleractinian coral.