Two divergent Symbiodinium genomes reveal conservation of a gene cluster for sunscreen biosynthesis and recently lost genes

• DOI: 10.1186/s12864-018-4857-9
• Publication Date: 2018-06-13T21:45:34Z
• Authors: Eiichi Shoguchi; Girish Beedessee; Ipputa Tada; Kanako Hisata; Takeshi Kawashima; Takeshi Takeuchi; Nana Arakaki; Manabu Fujie; Ryo Koyanagi; Michael C. Roy; Masanobu Kawachi; Michio Hidaka; Noriyuki Satoh; Chuya Shinzato
• Keywords: Symbiodinium; Gene cluster

The marine dinoflagellate, Symbiodinium, is a well-known photosynthetic partner for coral and other diverse, non-photosynthetic hosts in subtropical tropical shallows, where it comprises an essential component of ecosystems. Using molecular phylogenetics, the genus Symbiodinium has been classified into nine major clades, A-I, one reported differences among phenotypes their capacity to synthesize mycosporine-like amino acids (MAAs), which absorb UV radiation. However, genetic basis this difference synthetic unknown. To understand genetics underlying diversity, we report two draft genomes, from clade A, presumed have earliest branching clade, C, terminal branch.The nuclear genome A (SymA) more gene families than that with larger numbers organelle-related genes, including mitochondrial transcription factor (mTERF) Rubisco. While C (SymC) fewer families, displays specific expansions repeat domain-containing such as leucine-rich repeats (LRRs) retrovirus-related dUTPases. Interestingly, SymA encodes cluster MAA biosynthesis, potentially transferred endosymbiotic red alga (probably bacterial origin), while SymC completely lost these genes.Our analysis demonstrates appears evolved by losing biosynthesis cluster. In contrast conservation genes related ability, suffered family losses suggesting possible adaptation symbiosis. Overall, study implies ecology drives acquisition loss families.