Data from: Gene transfer from bacteria and archaea facilitated evolution of an extremophilic eukaryote

Some microbial eukaryotes, such as the extremophilic red alga Galdieria sulphuraria, can live in hot, toxic metal-rich, acidic environments. To elucidate the underlying molecular mechanisms of adaptation, we sequenced the 13.7 Mb genome of G. sulphuraria. This alga shows an enormous metabolic flexibility, growing either photoautotrophically or heterotrophically on more than 50 carbon sources. Environmental adaptation seems to have been facilitated by horizontal gene transfer from various bacteria and archaea, often followed by gene family expansion. At least 5% of protein-coding genes of G. sulphuraria were probably acquired horizontally. These proteins are involved in ecologically important processes ranging from heavy metal detoxification to glycerol uptake and metabolism. Thus, our findings show that a pan-domain gene pool has facilitated environmental adaptation in this unicellular eukaryote.部分微生物真核生物，如嗜极红藻硫色盖亚藻（Galdieria sulphuraria），可在高温、富含毒性重金属的酸性环境中存活。为阐明其适应极端环境的潜在分子机制，本研究对该藻的13.7 Mb（百万碱基对）基因组进行了测序。该红藻具备极强的代谢灵活性，可通过光合自养或异养方式利用50余种碳源生长。研究发现，其环境适应能力似乎得益于从多种细菌与古菌中获取的水平基因转移（horizontal gene transfer）事件，且此类转移后常伴随基因家族扩增。硫色盖亚藻至少5%的蛋白编码基因可能通过水平基因转移获得，这些蛋白参与了诸多具有重要生态意义的生理过程，涵盖重金属解毒、甘油摄取与代谢等多个环节。综上，本研究结果表明，跨域基因库助力了这一单细胞真核生物的环境适应过程。