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Acclimation to low ultraviolet‐B radiation increases photosystem I abundance and cyclic electron transfer with enhanced photosynthesis and growth in the cyanobacterium Nostoc sphaeroides
Author(s) -
Chen Zhen,
Jiang HaiBo,
Gao Kunshan,
Qiu BaoSheng
Publication year - 2020
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.14836
Subject(s) - photosynthesis , biology , acclimatization , plastoquinone , photoprotection , photosystem ii , photoinhibition , nostoc , photosystem i , botany , cyanobacteria , biophysics , photochemistry , biochemistry , chloroplast , chemistry , thylakoid , bacteria , genetics , gene
Summary Ultraviolet‐B radiation is known to harm most photosynthetic organisms with the exception of several studies of photosynthetic eukaryotes in which UV‐B showed positive effects. In this study, we investigated the effect of acclimation to low UV‐B radiation on growth and photosynthesis of the cyanobacterium Nostoc sphaeroides . Exposure to 0.08 W m −2 UV‐B plus low visible light for 14 d significantly increased the growth rate and biomass production by 16% and 30%, respectively, compared with those under visible light alone. The UV‐B acclimated cells showed an approximately 50% increase in photosynthetic efficiency (α) and photosynthetic capacity ( P max ), a higher PSI/PSII fluorescence ratio, an increase in PSI content and consequently enhanced cyclic electron flow, relative to those of non‐acclimated cells. Both the primary quinone‐type acceptor and plastoquinone pool re‐oxidation were up‐regulated in the UV‐B acclimated cells. In parallel, the UV‐B acclimated colonies maintained a higher rate of D1 protein synthesis following exposure to elevated intensity of UV‐B or visible light, thus functionally mitigating photoinhibition. The present data provide novel insight into photosynthetic acclimation to low UV‐B radiation and suggest that UV‐B may act as a positive ecological factor for the productivity of some photosynthetic prokaryotes, especially during twilight periods or in shaded environments.