Differential gene expression in skeletal organic matrix proteins of scleractinian corals associated with mixed aragonite/calcite skeletons under low mMg/Ca conditions

PeerJ

Tomihiko Higuchi¹  Ikuko Yuyama² 

[1] Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, Japan;Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan;

关键词: RNA-seq;    Biomineralization;    Aragonite;    Scleractinian coral;    Calcite;   

DOI  :  10.7717/peerj.7241

来源: DOAJ

【 摘 要 】

Although coral skeletons generally comprise aragonite crystals, changes in the molar Mg/Ca ratio (mMg/Ca) in seawater result in the incorporation of calcite crystals. The formation mechanism of aragonite and calcite crystals in the scleractinian coral Acropora tenuis was therefore investigated by RNA-seq analysis, using early growth stage calcite (mMg/Ca = 0.5) and aragonite (mMg/Ca = 5.2)-based corals. As a result, 1,287 genes were up-regulated and 748 down-regulated in calcite-based corals. In particular, sixty-eight skeletogenesis-related genes, such as ectin, galaxin, and skeletal aspartic acid-rich protein, were detected as up-regulated, and six genes, such as uncharacterized skeletal organic matrix protein 5, down-regulated, in low-Mg/Ca conditions. Since the number of down-regulated genes associated with the skeletal organic matrix of aragonite skeletons was much lower than that of up-regulated genes, it is thought that corals actively initiate construction of an aragonite skeleton by the skeletal organic matrix in low-Mg/Ca conditions. In addition, different types of skeletal organic matrix proteins, extracellular matrix proteins and calcium ion binding proteins appeared to change their expression in both calcite-formed and normal corals, suggesting that the composition of these proteins could be a key factor in the selective formation of aragonite or calcite CaCO3.

【 授权许可】

Unknown