Potential causes and consequences of rapid mitochondrial genome evolution in thermoacidophilic Galdieria (Rhodophyta)

BMC Evolutionary Biology

Debashish Bhattacharya¹  Louis Graf²  Seung In Park²  Hwan Su Yoon²  Chung Hyun Cho²  Claudia Ciniglia³  Eun Chan Yang⁴ 

[1] Department of Biochemistry and Microbiology, Rutgers University, 08901, New Brunswick, USA;Department of Biological Sciences, Sungkyunkwan University, 16419, Suwon, South Korea;Department of Environmental, Biological and Pharmaceutical Science and Technologies, University of Campania Luigi Vanvitelli, 81100, Caserta, Italy;Marine Ecosystem Research Center, Korea Institute of Ocean Science and Technology, 49111, Busan, South Korea;

关键词: Cyanidiophyceae;    Extremophile;    Mitogenome evolution;    Protein divergence;    Mitochondrial DNA replication;   

DOI  :  10.1186/s12862-020-01677-6

来源: Springer

【 摘 要 】

BackgroundThe Cyanidiophyceae is an early-diverged red algal class that thrives in extreme conditions around acidic hot springs. Although this lineage has been highlighted as a model for understanding the biology of extremophilic eukaryotes, little is known about the molecular evolution of their mitochondrial genomes (mitogenomes).ResultsTo fill this knowledge gap, we sequenced five mitogenomes from representative clades of Cyanidiophyceae and identified two major groups, here referred to as Galdieria-type (G-type) and Cyanidium-type (C-type). G-type mitogenomes exhibit the following three features: (i) reduction in genome size and gene inventory, (ii) evolution of unique protein properties including charge, hydropathy, stability, amino acid composition, and protein size, and (iii) distinctive GC-content and skewness of nucleotides. Based on GC-skew-associated characteristics, we postulate that unidirectional DNA replication may have resulted in the rapid evolution of G-type mitogenomes.ConclusionsThe high divergence of G-type mitogenomes was likely driven by natural selection in the multiple extreme environments that Galdieria species inhabit combined with their highly flexible heterotrophic metabolism. We speculate that the interplay between mitogenome divergence and adaptation may help explain the dominance of Galdieria species in diverse extreme habitats.

【 授权许可】

CC BY