Genetic and morphological characteristics of two ecotypes of Eustigmatos calaminaris sp. nov. (Eustigmatophyceae) inhabiting Zn- and Pb-loaded calamine mine spoils.

Abstract

Knowledge on species diversity and distribution of eustigmatophycean algae (Stramenopiles) in the environment is currently very limited. Some of them are considered promising organisms for industrial application. Phylogenetic analysis of two strains (E120, E5) of a coccoid microalga isolated from highly Zn-and Pb-polluted calamine mine spoils revealed that they belong to the genus Eustigmatos. Cells of both strains were morphologically identical. Some features of their vegetative cells and zoospores differed from other described nominal Eustigmatos species. 18S rDNA sequences of E120 and E5 were identical but also differed in two or three nucleotide substitutions from the other Eustigmatos species (E. vischeri, E. magnus, E. polyphem). Only 1 -3 nucleotide substitutions in 18S rDNA sequence were found among all the examined Eustigmatos species. ITS1-5.8S rDNA-ITS2 region was more variable (15 -22 differences) than 18S rDNA, except for E120 and E5 strains which differed in only one nucleotide substitution (in 5.8S rDNA). Genetic differences found between the isolated strains (E120, E5) and the other Eustigmatos species were comparable to those observed among all nominal Eustigmatos species studied. This suggests that the isolates represent a new species. The name Eustigmatos calaminaris sp. nov. (referred to the locality) has been proposed. The E120 strain from the mine spoil with higher heavy metal contents was more Zn-and Pb-resistant than E5 from the less polluted ground. Their high, though varied resistance to Zn/Pb stress, together with the very slight genetic divergence between them, indicate that they represent two ecotypes of the same new species.

Rediscovery of Tetraëdriella subglobosa Pascher, a member of the Eustigmatophyceae

“…Three different techniques were used to stimulate zoospore production. An exponentially growing culture in liquid medium was placed in darkness (wrapped in aluminum foil) for at least 18 h at either 20 °C (lee & Bold 1973) or at 10 °C (Trzcińska et al 2014), or fresh liquid medium was applied to the surface of a culture on agar medium that was over 1 month old which was then placed in darkness for at least 5 days (santos & leedale 1991).…”

Eustigmatophyceae

“…Since the seminal work of Hibberd (1981), knowledge of eustigmatophyte diversity has expanded with the transfer of additional species from the Xanthophyceae (Schnepf et al 1996;Přibyl et al 2012;Fawley and Fawley 2017) and the descriptions of new taxa (Lubián 1982;Karlson et al 1996;Krienitz et al 2000;Suda et al 2002;Trzcińska et al 2014;Fawley et al 2015), including four new monotypic genera (Preisig and Wilhelm 1989;Neustupa and Němcová 2001;Hegewald et al 2007;Nakayama et al 2015). Recent culture-based and environmental DNA cloning studies have shown that the diversity of the Eustigmatophyceae is much greater than previously expected (Fawley et al 2014).…”

Xanthophyte, Eustigmatophyte, and Raphidophyte Algae

“…Less often, eustigmatophytes may be epiphytic (growing on other plants) (Schumacher et al, 1966), epilithic (growing on rocks) (Poulton, 1930), or even as an endosymbiont in the freshwater sponge Corvomeyenia (Frost et al, 1997). Eustigmatophytes may also be common on soils (Hibberd, 1990b;Graham et al, 2009;Trzcyńska et al, 2014).…”

“…This peculiar feature gives the class its name: Eu = well developed; stigma = eyespot. The latter is a distinct, orange-red extraplastidial eyespot (Trzcyńska et al, 2014).…”