High salt-induced PSI-supercomplex is associated with high CEF and attenuation of state transitions

TitleHigh salt-induced PSI-supercomplex is associated with high CEF and attenuation of state transitions
Publication TypeJournal Article
Year of Publication2023
AuthorsKalra, I, Wang, X, Zhang, R, Morgan-Kiss, RM
JournalPhotosynthesis Research
Volume157
Issue2
Pagination65 - 84
Date Published09/2023
ISSN0166-8595
Keywordsacclimation, Antarctica, Chlamydomonas, Cyclic electron flow, PSI-supercomplex, salinity, state transitions
Abstract

While PSI-driven cyclic electron flow (CEF) and assembly of thylakoid supercomplexes have been described in model organisms like Chlamydomonas reinhardtii, open questions remain regarding their contributions to survival under long-term stress. The Antarctic halophyte, C. priscuii UWO241 (UWO241), possesses constitutive high CEF rates and a stable PSI-supercomplex as a consequence of adaptation to permanent low temperatures and high salinity. To understand whether CEF represents a broader acclimation strategy to short- and long-term stress, we compared high salt acclimation between the halotolerant UWO241, the salt-sensitive model, C. reinhardtii, and a moderately halotolerant Antarctic green alga, C. sp. ICE-MDV (ICE-MDV). CEF was activated under high salt and associated with increased non-photochemical quenching in all three Chlamydomonas species. Furthermore, high salt-acclimated cells of either strain formed a PSI-supercomplex, while state transition capacity was attenuated. How the CEF-associated PSI-supercomplex interferes with state transition response is not yet known. We present a model for interaction between PSI-supercomplex formation, state transitions, and the important role of CEF for survival during long-term exposure to high salt.

URLhttps://link.springer.com/10.1007/s11120-023-01032-y
DOI10.1007/s11120-023-01032-y
Short TitlePhotosynth Res