Functional characterisation of Ostreococcus tauri phototropin

Sullivan, S., Petersen, J., Blackwood, L., Papanatsiou, M. and Christie, J. M. (2016) Functional characterisation of Ostreococcus tauri phototropin. New Phytologist, 209(2), pp. 612-623. (doi:10.1111/nph.13640) (PMID:26414490)

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Abstract

Phototropins (phots) regulate a range of adaptive processes in plants that serve to optimize photosynthetic efficiency and promote growth. Light sensing by Arabidopsis thaliana phots is predominantly mediated by the Light, Oxygen and Voltage sensing 2 (LOV2) flavin-binding motif located within the N-terminus of the photoreceptor. Here we characterize the photochemical and biochemical properties of phot from the marine picoalga Ostreococcus tauri phototropin (Otphot) and examine its ability to replace phot-mediated function in Arabidopsis. Photochemical properties of Otphot rely on both LOV1 and LOV2. Yet, biochemical analysis indicates that light-dependent receptor autophosphorylation is primarily dependent on LOV2. As found for Arabidopsis phots, Otphot associates with the plasma membrane and partially internalizes, albeit to a limited extent, in response to blue-light irradiation. Otphot is able to elicit a number of phot-regulated processes in Arabidopsis, including petiole positioning, leaf expansion, stomatal opening and chloroplast accumulation movement. However, Otphot is unable to restore phototropism and chloroplast avoidance movement. Consistent with its lack of phototropic function in Arabidopsis, Otphot does not associate with or trigger dephosphorylation of the phototropic signalling component Non-Phototropic Hypocotyl 3 (NPH3). Taken together, these findings indicate that the mechanism of action of plant and evolutionarily distant algal phots is less well conserved than previously thought.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Sullivan, Dr Stuart and Papanatsiou, Dr Maria and Petersen, Dr Jan and Christie, Professor John
Authors: Sullivan, S., Petersen, J., Blackwood, L., Papanatsiou, M., and Christie, J. M.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:New Phytologist
Publisher:Wiley-Blackwell Publishing Ltd.
ISSN:0028-646X
ISSN (Online):1469-8137
Published Online:28 September 2015

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
581491Regulation of Auxin Fluxes Required For Phototropic GrowthJohn ChristieBiotechnology and Biological Sciences Research Council (BBSRC)BB/J016047/1RI MOLECULAR CELL & SYSTEMS BIOLOGY
659801Photoreceptor Engineering to Modulate Plant GrowthJohn ChristieBiotechnology and Biological Sciences Research Council (BBSRC)BB/M002128/1RI MOLECULAR CELL & SYSTEMS BIOLOGY