Molecular diversity and gene expression analyses of stony corals showing different degree of bleaching stages from the Hainan Island (South China Sea)

珊瑚礁是海洋水域中的生物多样性和高生产力的生态系统，几乎没有营养物质。大多数珊瑚礁的结构基础是石质珊瑚群体的微小息肉，形成专有的共生环境，与单细胞、虫黄杆菌进行营养交换。石珊瑚属于珊瑚亚纲(Cnidaria)，代表后生动物的基本成员。近几十年来，南海中国沿海地区经济的快速发展和人口的增长，导致了许多中国珊瑚礁的严重退化。此外，脆弱共生体的破坏被称为珊瑚漂白，这实际上威胁到世界各地珊瑚礁的活力和生产力。为了对珊瑚礁及其制品采取可持续的保护措施，迫切需要对漂白过程的分子理解以及与珊瑚礁和共生体多样性的相关性进行详细的研究。本研究旨在调查海南岛(南中国海)石珊瑚及其内共生体的分子多样性。将确定漂白过程中可能的关键基因，特别是变异组蛋白基因的表达模式，以分析它们在漂白过程中的作用。群体内表达水平的变异性及其与珊瑚和共生体多样性的相关性将通过DNA和RNA提取的方法进行分析，从而能够对群体中单个珊瑚虫的分析。因此，这项研究将对自然种群中发生的漂白分子过程提供重要的见解，并可以揭示南中国海不同珊瑚礁之间的遗传关系。此外，这可能是一项创新的工作，寻找合适的标记来研究硬指目动物的系统发育。结果将支持有效的珊瑚礁管理，特别是在中国沿海，并使更好地评估全球珊瑚礁的威胁。

Coral reefs are biological diverse and high productive ecosystems in marine waters that contain few nutrients. The structural foundations of most coral reefs are tiny polyps of stony coral colonies forming a obligate symbioses to unicellular ‚zooxanthella‘ for nutrition exchange. Stony corals (Scleractinia) belong to the taxon Anthozoa (Cnidaria) representing a basal member of Metazoa. The rapid economic development and population growth in the coastal regions of South China Sea over the last several decades leaded to serious degration of many Chinese Coral Reefs. Furthermore, the breakdown of the delicate symbioses is called ‚coral bleaching‘, which actually threatens the vitality and productivity of coral reefs worldwide. Detailed studies on the molecular understanding of bleaching process as well as the dependences to the scleractinian and symbiont diversity are urgently needed for sustainable protection measures of the coral reefs and their productions.The present study is designed to investigate the molecular diversity of stony corals and their endosymbionts from Hainan Island (South China Sea). The expression pattern of possible key-genes of the bleaching process, especially variant histone gene, will be determined to analyze their roles in the bleaching process. The expression level variability within a colony as well as their correlations to coral and symbiont diversity will be analyzed using a DNA- and RNA-extraction methods that enables the analyses of individual polyps of a colony.Thus, this study will give important insights in the molecular process of bleaching take place in natural populations and can show genetic relationships between different coral reefs in the South China Sea. Additionally, it could be an innovative work to detect suitable markers for scleractinian phylogeny. The results will support effective coral reef management especially on the chinese coast and enable a better evaluation of the threat of corals reefs worldwide.