Venkatasalam, Shanmugabalaji

Nom

Venkatasalam, Shanmugabalaji

Affiliation principale

Institut de biologie

Identifiants

https://libra.unine.ch/handle/123456789/30601

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Accès libre
Plastoquinone homoeostasis by Arabidopsis proton gradient regulation 6 is essential for photosynthetic efficiency
(2019-6-20)
Pralon, Thibaut
;
Venkatasalam, Shanmugabalaji
;
Longoni, Fiamma
;
Ksas, Brigitte
;
Collombat, Joy
;
Desmeules, Saskia
;
Glauser, Gaëtan
;
Havaux, Michel
;
Finazzi, Giovanni
;
Kessler, Félix
Photosynthesis produces organic carbon via a light-driven electron flow from H2O to CO2 that passes through a pool of plastoquinone molecules. These molecules are either present in the photosynthetic thylakoid membranes, participating in photochemistry (photoactive pool), or stored (non-photoactive pool) in thylakoid-attached lipid droplets, the plastoglobules. The photoactive pool acts also as a signal of photosynthetic activity allowing the adaptation to changes in light condition. Here we show that, in Arabidopsis thaliana, proton gradient regulation 6 (PGR6), a predicted atypical kinase located at plastoglobules, is required for plastoquinone homoeostasis, i.e. to maintain the photoactive plastoquinone pool. In a pgr6 mutant, the photoactive pool is depleted and becomes limiting under high light, affecting short-term acclimation and photosynthetic efficiency. In the long term, pgr6 seedlings fail to adapt to high light and develop a conditional variegated leaf phenotype. Therefore, PGR6 activity, by regulating plastoquinone homoeostasis, is required to cope with high light.