Roles of a membrane-bound caleosin and putative peroxygenase in biotic and abiotic stress responses in Arabidopsis

Denis Murphy, Mark Partridge

Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid


ABSTRACT We report here the localisation and properties of a new membrane-bound isoform of caleosin and its putative role as a peroxygenase involved in oxylipin metabolism during biotic and abiotic stress responses in Arabidopsis. Caleosins are a family of lipid-associated proteins that are ubiquitous in plants and true fungi. Previous research has focused on lipid-body associated, seed-specific caleosins that have peroxygenase activity. Here, we demonstrate that a separate membrane-bound constitutively expressed caleosin isoform (Clo-3) is highly upregulated following exposure to abiotic stresses, such as salt and drought, and to biotic stress such as pathogen infection. The Clo-3 protein binds one atom of calcium per molecule, is phosphorylated in response to stress, and has a similar peroxygenase activity to the seed-specific Clo-1 isoform. Clo-3 is present in microsomal and chloroplast envelope fractions and has a type I membrane orientation with about 2 kDa of the C terminal exposed to the cytosol. Analysis of Arabidopsis ABA and related mutant lines implies that Clo-3 is involved in the generation of oxidised fatty acids in stress related signalling pathways involving both ABA and salicylic acid. We propose that Clo-3 is part of an oxylipin pathway induced by multiple stresses and may also generate fatty acid derived anti-fungal compounds for plant defence.
Iaith wreiddiolSaesneg
Tudalennau (o-i)796 - 806
Nifer y tudalennau10
CyfnodolynPlant Physiology and Biochemistry
Rhif cyhoeddi9
Dynodwyr Gwrthrych Digidol (DOIs)
StatwsCyhoeddwyd - 1 Ion 2009

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