sp. nov (Chlorellaceae, Chlorophyta) and Analysis of Its Organelle Genomes.

Chlorellacean members are common in aquatic or subaerial habitats, and many of them have significant economic value. Taxonomic reports and organelle genome data for the clade, an important subgroup within this family, are limited, hindering the understanding and exploitation of this clade. In this study, a fusiform-celled strain, FACHB-3607, was isolated from a pond in China. Through examination of morphological characteristics and phylogenetic analyses of rbcL, 18S rDNA, and ITS, it was identified as a new species within the clade, named sp. nov. In addition, this study provided a first insight into the organellar genomes of the genus . The chloroplast had a 99.8 kb genome, and the mitochondrion had a 40.8 kb genome, which are moderate sizes within the clade. Phylogenomic analysis showed that is most closely related to sp. "desiccata", followed by . In contrast, was the most distantly related species. The organelle genomes of the clade display dynamic evolution, reflected in variations in genome size, gene content and order, and selection pressure. This research enhances our knowledge of species diversity and evolutionary history in the clade.