Cryptic diversity within the genus Pseudomuriella Hanagata (Chlorophyta, Chlorophyceae, Sphaeropleales) assessed using four Barcode markers
Fučíková, Karolina; Rada, Jared C.; Lukešová, Alena; Lewis, Louise A.
Assessing species diversity in green coccoid algae traditionally has been limited by their character-poor morphology observable by light microscopy. The problem becomes apparent when alternative methods, especially the use of molecular sequence data, are implemented. These methods often reveal cryptic diversity and help clarify phylogenetic affiliations of green coccoids. The present study focuses on the genus Pseudomuriella Hanagata, a genetically diverse but morphologically uniform taxon, using a phylogenetic approach based on a four-gene phylogeny. Suitability of the four individual molecular markers, the nuclear internal transcribed spacer 2, the plastid genes rbcL and tufA, and the mitochondrial cox1 gene, for species recognition (barcoding) was assessed by comparing their performance in species-level resolution within the Pseudomuriella clade, while also considering their ease of use. All four genes examined were found to contain variation usable for species-level resolution, and provided largely consistent phylogenies. Cox1 was about twice as variable among species as the other three markers but reliable amplification required taxon specific primers. A joint use of the four markers may be the ideal tool for barcoding cryptic green algal species, but both rbcL and tufA appear to be the most practical combination of sufficient phylogenetic signal and ease of use.