Photosynthesis in relation to D1, PsaA and Rubisco in marine and brackish water ecotypes of Fucus vesiculosus and Fucus radicans (Phaeophyceae)

Abstract

The aim of this study was to investigate photosynthetic differences between the marine, Norwegian Sea ecotype and the brackish, Bothnian Sea ecotype of F. vesiculosus and F. radicans and to see whether photosynthetic differences could be connected with the relative amounts of D1 protein (PSII), PsaA (PSI) protein and/or Rubisco. For this purpose, we tested if a higher photosynthetic maximum (P max ) in the Atlantic Ocean ecotype of F. vesiculosus relative to the Baltic Sea ecotype, and an increase of the P max in Baltic Sea ecotype of F. vesiculosus at higher salinity, could be due to an increase in the relative amounts of Rubisco. The proteins have been evaluated on a relative basis. Immunoblot signals showed that the amount of Rubisco was higher in both ecotypes of F. vesiculosus than in F. radicans, but no differences could be detected between the two ecotypes of F. vesiculosus. The results suggest an uneven photosystem protein stoichiometry in Fucus, with more of the PSI protein PsaA relative to the PSII protein D1. The difference in P max between the two ecotypes of F. vesiculosus might be related to the difficulties for the algae to adapt to the environment in Bothnian Sea.

Geographic variation in fitness‐related traits of the bladderwrack Fucus vesiculosus along the Baltic Sea‐North Sea salinity gradient

“…In this context, our large-scale trends provide additional support for the hypothesis that physiological costs for osmoregulation in low salinities (particularly below 10) affect the photosynthetic system of F. vesiculosus, interfering with the energetic balance and development of the alga (Gylle, Nygård, Svan, Pocock, & Ekelund, 2013;Nygård & Dring, 2008;Nygård & Ekelund, 2006). In addition to the impact of low salinity, frond length was negatively affected by wave exposure confirming what previous comparisons between F. vesiculosus from exposed and sheltered sites already observed (Bäck, 1993; Bäck et al, 1992a).…”

Cooperation Between Photosynthetic and Antioxidant Systems: An Important Factor in the Adaptation of Ulva prolifera to Abiotic Factors on the Sea Surface

“…NPQ acts by dissipating excess energy in the LHCs as heat to ensure that the thalli are adapting to the environmental changes (Li et al, 2009). CEF around PSI is an important factor in the adaptation of macroalgae to dramatically changing environments on the sea surface, such as changes in temperature, light, saline stress, desiccation, and rehydration (Gao and Wang, 2012; Gao et al, 2013, 2015; Gylle et al, 2013).…”

Salinity and Desiccation Induced Oxidative Stress Acclimation in Seaweeds

“…The limitation of photosynthetic carbon fixation during dehydration decreases the utilisation of NADPH with a decline in the NADP + level, a major acceptor of electrons in PSI. Further, to this line of research Gylle, Nygard, Svan, Pocock, and Ekelund (2013) evaluated the differences in relative amount of either D1 (Chlorophyll a binding core protein in PSII), PsaA (Chlorophyll a binding core protein in PSI) and Rubisco in Fucus sp. The damage to the oxygen-evolving complex of PSII and to the PSII reaction centres has commonly observed in desiccated thalli (Gao et al, 2011;Xia, Li, & Zou, 2004).…”