Molecular and morphological delimitation of species in Strombomonas (Euglenaceae) including a protocol for DNA isolation utilising a chelating resin

Abstract

AbstractAlthough Strombomonas verrucosa has been the type of the genus name for almost 100 years, its lack of clear diagnostic traits has rendered morphological distinction from its congeners almost impossible. As such, a study was conducted combining previously unused morphological data (chloroplast characters) with molecular data (sequences of nuclear SSU, LSU and plastid‐encoded SSU rDNA) and extensive literature review. The study focused on environmental samples obtained from Poland and China and resulted in 51 new sequences representing three molecular markers (17 nSSU, 16 nLSU and 18 cpSSU rDNA). Revised delimitations of the genus Strombomonas and its type S. verrucosa are presented that include new and detailed diagnostic characters. In addition to the type, we recognize nine species: S. acuminata, S. borystheniensis, S. eurystoma, S. fluviatilis, S. gibberosa, S. maxima, S. ovalis, S. schauinslandii, S. triquetra. Three of these are incorporated into a phylogeny for the first time (S. fluviatilis, S. gibberosa, S. schauinslandii). To improve the efficiency of DNA isolation from loricate cells, a protocol utilising a chelating resin for DNA isolation – following the lead of diatomologists – has been adjusted for Euglenaceae and is also presented.