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Phytosphingosine-phosphate is a signal for AtMPK6 activation and Arabidopsis response to chilling

Abstract :

Long-chain bases (LCBs) are pleiotropic sphingolipidic signals in eukaryotes. We investigated the source and function of phytosphingosine-1-phosphate (PHS-P), a phospho-LCB rapidly and transiently formed in Arabidopsis thaliana on chilling.PHS-P was analysed by thin-layer chromatography following in vivo metabolic radiolabelling. Pharmacological and genetic approaches were used to identify the sphingosine kinase isoforms involved in cold-responsive PHS-P synthesis. Gene expression, mitogen-activated protein kinase activation and growth phenotypes of three LCB kinase mutants (lcbk1, sphk1 and lcbk2) were studied following cold exposure. Chilling provoked the rapid and transient formation of PHS-P in Arabidopsis cultured cells and plantlets. Cold-evoked PHS-P synthesis was reduced by LCB kinase inhibitors and abolished in the LCB kinase lcbk2 mutant, but not in lcbk1 and sphk1 mutants. lcbk2 presented a constitutive AtMPK6 activation at 22°C. AtMPK6 activation was also triggered by PHS-P treatment independently of PHS/PHS-P balance. lcbk2 mutants grew comparably with wild-type plants at 22 and 4°C, but exhibited a higher root growth at 12°C, correlated with an altered expression of the cold-responsive DELLA gene RGL3. Together, our data indicate a function for LCBK2 in planta. Furthermore, they connect PHS-P formation with plant response to cold, expanding the field of LCB signalling in plants.

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Contributeur : Okina Université d'Angers <>
Soumis le : jeudi 9 septembre 2021 - 13:59:51
Dernière modification le : vendredi 10 septembre 2021 - 03:35:21

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Christelle Dutilleul, Ghouziel Benhassaine-Kesri, Chantal Demandre, Nathalie Rézé, Alban Launay, et al.. Phytosphingosine-phosphate is a signal for AtMPK6 activation and Arabidopsis response to chilling. New Phytologist, 2012, 194 (1), pp.181 - 191. ⟨10.1111/j.1469-8137.2011.04017.x⟩. ⟨hal-03339366⟩



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