ISOLATION AND CHARACTERIZATION OF PARMALES (HETEROKONTA/HETEROKONTOPHYTA/STRAMENOPILES) FROM THE OYASHIO REGION, WESTERN NORTH PACIFIC¹

Abstract

A small siliceous species of marine phytoplankton, order Parmales (Heterokonta), was isolated and characterized for the first time with the aid of a fluorescent silicon tracer 2-(4-pyridyl)-5-([4-(2-dimethylaminoethylaminocarbamoyl)-methoxy]phenyl)oxazole (PDMPO). This dye was easily detected by clear fluorescence in newly produced silica cell plates. Our isolate was surrounded by eight smooth plates without any ornamentation, suggesting a similarity to Triparma laevis B. C. Booth. TEM observation showed the typical ultrastructure of photosynthetic heterokontophytes; with two chloroplast endoplasmic reticulate membranes, a girdle lamella, three thylakoid lamellae, and mitochondrion with tubular cristae. Molecular phylogenetic analyses of SSU rDNA and rbcL genes showed that the parmalean alga was within the bolidophycean clade of autotrophic naked flagellates and a sister group of diatoms. HPLC analysis detected chl a, c1 + c2 , and c3 ; fucoxanthin; and diadinoxanthin as major photosynthetic pigments, and a composition that is shared with Bolidophyceae and diatoms. Together, these data indicate a close evolutionary relationship between Parmales, Bolidophyceae, and diatoms. The PDMPO-staining procedure should accelerate isolation of other Parmales species, helping to establish their diversity and aiding quantitative study of their role in oceanic processes.

Mesoscale distribution and functional diversity of picoeukaryotes in the first-year sea ice of the Canadian Arctic

“…This recently discovered picoeukaryotes (Guillou et al, 1999a) form one phylogenetic clade with Parmalean algae Triparma (Ichinomiya et al, 2011), which is also targeted by probe Bolido02. Phylotypes related to bolidophytes were previously reported from pancake sea ice (Majaneva et al, 2012).…”

Sex is a ubiquitous, ancient, and inherent attribute of eukaryotic life

“…The second is the class Bolidophyceae comprised of minute naked marine flagellates discovered 15 y ago and shown to be a sister group of diatoms (27). In 2011, both groups were tied together by the amazing finding that the first (and thus far only) molecularly characterized parmalean species is phylogenetically nested among bolidophytes (28). This led to the hypothesis that the different bolidophyte and parmalean morphotypes are actually alternating stages of a biphasic life cycle of the same algal group (26,28).…”

“…In 2011, both groups were tied together by the amazing finding that the first (and thus far only) molecularly characterized parmalean species is phylogenetically nested among bolidophytes (28). This led to the hypothesis that the different bolidophyte and parmalean morphotypes are actually alternating stages of a biphasic life cycle of the same algal group (26,28). In analogy (or as a matter of fact perhaps homology) to diatoms, the flagellated bolidophytes represent the haploid stage (which was recently supported by a transcriptomic study of a bolidophyte isolate) (29), whereas the armored coccoid Parmales probably represent the diploid stage.…”

Competition between Silicifiers and Non-silicifiers in the Past and Present Ocean and Its Evolutionary Impacts

“…Many new genes associated with biosilicification have been identified (Kotzsch et al, 2016), including the recognition that active silicon transporter gene families are much more ancient and widely distributed amongst the eukaryotes than previously thought (Marron et al, 2016b). This has been complemented by the discovery of new silicifying species (Ichinomiya et al, 2011), most notably silicon accumulation in some strains of the hugely ecologically important cyanobacteria Synechococcus (Baines et al, 2012). Combined with metagenomic surveys and geochemical monitoring (Mutsuo et al, 2015;Sunagawa et al, 2015) it will be possible to gain a much deeper knowledge of the role of different marine groups in silicon biogeochemistry and how competitive interactions govern their ecology, distribution and response to changing climatic conditions (Mock et al, 2016).…”