[A-CG41] Coastal Ecosystems -2. Coral reefs, seagrass and macroalgal beds, and mangroves

[ACG41-P04] Coral bleaching countermeasures by supplying metal-containing feed ~evaluation the effect at gene expression levels~

*Ikuko Yuyama¹, Naoko Yasuda², Sayaka Higa², Sung-Yin Yang³, Sylvain Agostini ³, Tomihiko Higuchi⁴, Toshihiro Miyajima⁴, Takashi Nakamura⁵, Hiroyuki Fujimura² (1.Yamaguchi University, 2.University of the Ryukyus, 3.University of Tsukuba, 4.The University of Tokyo , 5.Tokyo Institute of Technology)

Keywords:coral bleaching, feeding effect, RNA-seq

Under high temperature stress, the reactive oxygen species (ROS) generated from symbiotic algae triggers the coral bleaching response. There is a possibility that the antioxidant enzymes containing metal ions such as Fe, Mn, and Zn, have an effect on the mitigation of ROS stress. Therefore, we hypothesized that the supply of metal ions promotes antioxidant activity and mitigates the bleaching response. In this study, the corals were fed with a metal-containing diet, and investigated the effect on the bleaching response at gene expression level.

We used Acropora hyacinthus collected around Sesoko Island, and they were fed with Artemia and metal-fortified yeast. Furthermore, the coral was incubated at an increasing temperature, and physiological responses and gene expression change of coral and their symbiotic algae were investigated. Coral was fixed at the time point when the bleaching response was observed, and large-scale gene expression analysis by Next Generation Sequencing was performed. We identified 25,069 contigs derived from Acropora hyacinthus by de novo assembled of the short reads. Then, expression levels of each contigs were estimated, and the gene expression related to the physiological response of corals was investigated. Results showed that the expression level of genes related to proto-oncogene and CuZnSOD of corals was increased by temperature stress. [H1] These gene expression changes tended to be mitigated by feeding with artemia or yeast. Furthermore, a result of canonical correlation analysis (CCA) using the physiological data and the gene expression data showed that genes related to mucin metabolism and vitamin B12 were associated with the changes in symbiont density. Based on these gene expression levels, we discussed the effects of metal-containing diet on mitigating coral bleaching reactions.