Abstract
Bryopsidales (Chlorophyta) are cultured and consumed in several regions of the planet and are known for their high nutritional value and bioprospection potential, due to a high content of relevant polar lipids and polysaccharides. Among other characteristic features, these marine algae are known for possessing unique photosynthetic pigment-protein complexes and for the absence (in nearly all species investigated) of a functional xanthophyll cycle, a ubiquitous photoprotection mechanism present in most algae and plants. With the aim of characterizing the photophysiology of this atypical group of algae, we investigated the changes in pigment content and polar lipidome of two Bryopsidales species (Codium tomentosumandBryopsis plumosa) exposed for 7 days to low or high irradiance (20 vs. 1,000 μmol photons m–2s–1). Our results show that high light has a strong effect on the pigment composition, triggering the time-dependent accumulation of all-trans-neoxanthin (t-Neo) and violaxanthin (Viola). High light-acclimated macroalgae also displayed a shift in the characteristic polar lipidome, including a trend of accumulation of lyso-glycolipids, and highly unsaturated phospholipids and betaine lipids. We hypothesize that the observed shifts on the lipid composition could promote the interaction betweent-Neo and Viola with the siphonaxanthin–chlorophyll–protein complexes (SCP) of photosystem II (PSII) within the thylakoid membranes of the chloroplasts. Light induced changes in pigment and lipid composition could contribute to the fitness of Bryopsidales algae by reducing damages to the photosynthetic apparatus under increased irradiance.
Highlights
Bryopsidales is a monophyletic order of siphonous green algae with high ecological relevance in both tropical and temperate marine coastal ecosystems (Cremen et al, 2019)
We investigated photophysiological changes in two different Bryopsidales species, Codium tomentosum (Stackhouse, 1797) and Bryopsis plumosa (Agardh, 1823), with the aim of identifying key players involved in photoprotection and/or in enhancing the photosynthetic performance under increased irradiance, by (i) characterizing the time-dependent changes in the pigment composition in response to high light and (ii) analyzing the changes in the polar lipidome in high light acclimated algae, focusing on lipid classes with known relevance for the structure and functionality of chloroplast membranes and molecules possibly involved in photoprotection
Our results show that high irradiance triggers time-dependent accumulation of the putative photoprotective xanthophylls t-Neo and Viola and a shift in the polar lipidome that could correspond to a rearrangement of chloroplast membranes, possibly allowing a better photosynthetic performance under high light
Summary
Bryopsidales is a monophyletic order of siphonous green algae with high ecological relevance in both tropical and temperate marine coastal ecosystems (Cremen et al, 2019) These organisms have received increasing attention due to their remarkable content of valuable polar lipids and polysaccharides with potential pharmaceutical and nutraceutical applications (e.g., Maeda et al, 2012; Arata et al, 2015; Santos et al, 2015; Fleurence and Levine, 2016). Photoacclimation of Bryopsidales Algae some species of the genera Codium and Caulerpa are amongst the most popular edible macroalgae and listed as delicacies in gourmet cuisine (Paul et al, 2014; Pérez-Lloréns et al, 2018) Despite their relevance on both ecological and economical levels, the photophysiology of Bryopsidales is poorly understood. The mechanisms of photoprotection necessary for these algae to cope with increased irradiance, relevant in their natural habitats during low tides or summer, remain largely unexplored
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
