A siphonous morphology affects light-harvesting modulation in the intertidal green macroalga Bryopsis corticulans (Ulvophyceae)

Vasco Giovagnetti, Guangye Han, Maxwell A. Ware, Petra Ungerer, Xiaochun Qin, Wen Da Wang, Tingyun Kuang, Jian Ren Shen, Alexander V. Ruban

    Research output: Contribution to journalArticlepeer-review

    15 Citations (Scopus)

    Abstract

    Main conclusion: The macroalga Bryopsis corticulans relies on a sustained protective NPQ and a peculiar body architecture to efficiently adapt to the extreme light changes of intertidal shores. During low tides, intertidal algae experience prolonged high light stress. Efficient dissipation of excess light energy, measured as non-photochemical quenching (NPQ) of chlorophyll fluorescence, is therefore required to avoid photodamage. Light-harvesting regulation was studied in the intertidal macroalga Bryopsis corticulans, during high light and air exposure. Photosynthetic capacity and NPQ kinetics were assessed in different filament layers of the algal tufts and in intact chloroplasts to unravel the nature of NPQ in this siphonous green alga. We found that the morphology and pigment composition of the B. corticulans body provides functional segregation between surface sunlit filaments (protective state) and those that are underneath and undergo severe light attenuation (light-harvesting state). In the surface filaments, very high and sustained NPQ gradually formed. NPQ induction was triggered by the formation of transthylakoid proton gradient and independent of the xanthophyll cycle. PsbS and LHCSR proteins seem not to be active in the NPQ mechanism activated by this alga. Our results show that B. corticulans endures excess light energy pressure through a sustained protective NPQ, not related to photodamage, as revealed by the unusually quick restoration of photosystem II (PSII) function in the dark. This might suggest either the occurrence of transient PSII photoinactivation or a fast rate of PSII repair cycle.

    Original languageEnglish
    Pages (from-to)1293-1306
    Number of pages14
    JournalPlanta
    Volume247
    Issue number6
    DOIs
    Publication statusPublished - Jun 1 2018

    Keywords

    • Bryopsis corticulans
    • Intertidal algae
    • LHCSR
    • Light harvesting
    • Non-photochemical quenching
    • PsbS

    ASJC Scopus subject areas

    • Genetics
    • Plant Science

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