Mitochondrial genome of bacillariophycean diatoms reveals loss, gain, and re-loss of genes

Abstract

Diatoms are the play a role as primary producer in the marine ecosystem and involved in energy, carbon, nitrogen, and silicate exchanges between the water column and sediments. In the Bacillariophyceae, Bacillariales and Naviculales are representative orders that are ubiquitous and rich in species, ca. 5,000 and 1,100 spp, respectively. However, systematics and evolutionary studies have largely relied on morphological and ultrastructural characteristic and a handful nuclear and plastid genes (i.e., LSU and SSU rRNA, and rbcL). In present study, we determined five new mitochondrial genomes (mtDNA) from Bacillariales and compiled with all available dataset (total 25 mtDNA) to establish a robust phylogeny. The dataset encompassed 33 protein coding genes (7,968 amino acids) of 13 species from two bacillariophycean orders. The best phylogeny reveals a monophyly of Bacillariales and Naviculales with maximum support values and basal position of Fragilariales within the class. Based on the best phylogeny, Naviculales showed the loss, gain, and re-loss of genes, such as atp8, rps7, and rps11 in mtDNA. We demonstrated the implication of mtDNA data to understand evolutionary history of diatoms.resentative orders that are ubiquitous and rich in species, ca. 5,000 and 1,100 spp, respectively. However, systematics and evolutionary studies have largely relied on morphological and ultrastructural characteristic and a handful nuclear and plastid genes (i.e., LSU and SSU rRNA, and rbcL). In present study, we determined five new mitochondrial genomes (mtDNA) from Bacillariales and compiled with all available dataset (total 25 mtDNA) to establish a robust phylogeny. The dataset encompassed 33 protein coding genes (7,968 amino acids) of 13 species from two bacillariophycean orders. The best phylogeny reveals a monophyly of Bacillariales and Naviculales with maximum support values and basal position of Fragilariales within the class. Based on the best phylogeny, Naviculales showed the loss, gain, and re-loss of genes, such as atp8, rps7, and rps11 in mtDNA. We demonstrated the implication of mtDNA data to understand evolutionary history of diatoms.