Divinyl chlorophyll a in the marine eukaryotic protist Alexandrium ostenfeldii (Dinophyceae)

Abstract

Here it is reported the first detection of DV-chl a together with the usual chl a in the marine dinoflagellate Alexandrium ostenfeldii from the Baltic Sea. Growth response and photosynthetic parameters were examined at two irradiances (80 and 240 μmol photons m(-2) s(-1)) and temperatures (15 °C and 19 °C) in a divinylic strain (AOTV-OS20) versus a monovinylic one (AOTV-OS16), using in vivo chl a fluorescence kinetics of PSII to characterize photosynthetic parameters by pulse amplitude modulated fluorescence, (14)C assimilation rates and toxin analyses. The divinylic isolate exhibited slower growth and stronger sensitivity to high irradiance than normal chl a strain. DV-chl a : chl a ratios decreased along time (from 11.3 to < 0.5 after 10 months) and to restore them sub-cloning and selection of strains with highest DV-chl a content was required. A mutation and/or epigenetic changes in the expression of divinyl reductase gene/s in A. ostenfeldii may explain this altered pigment composition. Despite quite severe limitations (reduced fitness and gradual loss of DV-chl a content), the DV-chl a-containing line in A. ostenfeldii could provide a model organism in photosynthetic studies related with chl biosynthesis and evolution.

Comparative ecophysiology of Dinophysis acuminata and D. acuta (DINOPHYCEAE, DINOPHYSIALES): effect of light intensity and quality on growth, cellular toxin content, and photosynthesis

“…(), as modified by Rodríguez et al. (). Pigment identification was performed by UV‐VIS diode‐array spectroscopy (350–750 nm), co‐chromatography with standards obtained from SCOR reference cultures (Jeffrey et al.…”

“…To COMPARATIVE ECOPHYSIOLOGY OF DINOPHYSIS SPECIES avoid peak distortion the automatic injector was programmed, following Zapata and Garrido (1991), to mix samples with water by consecutively placing 70 lL water, 130 lL sample and 30 lL water in the injection loop. Pigment separation was carried out using a Waters Alliance HPLC System (Waters Corporation, Milford, MA, USA) consisting of a 2,695 separations module and a Waters 996 diode-array detector following Zapata et al (2000), as modified by Rodr ıguez et al (2016). Pigment identification was performed by UV-VIS diode-array spectroscopy (350-750 nm), co-chromatography with standards obtained from SCOR reference cultures (Jeffrey et al 1997) and the mixed phytoplankton pigments standard from DHI (Hoersholm, Denmark).…”

Two Unrelated 8-Vinyl Reductases Ensure Production of Mature Chlorophylls in Acaryochloris marina

“…8V-Chl a dominates in Prochlorococcus spp. ( 4 ) and in a recently isolated strain of the marine eukaryotic protist Alexandrium ostenfeldii ( 40 ), and the unreduced form of the pigment is tolerated in plant and cyanobacterial mutants with lesions in 8VR-encoding genes ( 6 , 13 , 14 ). 8V-Chl d , however, has yet to be detected in nature.…”

Yellow-Leaf 1 encodes a magnesium-protoporphyrin IX monomethyl ester cyclase, involved in chlorophyll biosynthesis in rice (Oryza sativa L.)

“…T-DNA insertion into OsChlH caused impediment of Chl biosynthesis and subsequent death of the plants [10]. Divinyl reductase (DVR) converts 8-vinyl groups on various chlorophyll intermediates to ethyl groups, and is indispensable for Chl biosynthesis [11–13]. The OsDVR gene mutant exhibited a yellow-green leaf phenotype, reduced Chl level, arrested chloroplast development, and retarded growth rate [13].…”

“…Divinyl reductase (DVR) converts 8-vinyl groups on various chlorophyll intermediates to ethyl groups, and is indispensable for Chl biosynthesis [11–13]. The OsDVR gene mutant exhibited a yellow-green leaf phenotype, reduced Chl level, arrested chloroplast development, and retarded growth rate [13]. In the last step of Chl biosynthesis, Chl b is synthesized from Chl a through the oxidation of a methyl group on the D ring, which is catalyzed by chlorophyllide a oxygenase (CAO) [14–16].…”