AQUA1 is a mercury sensitive poplar aquaporin regulated at transcriptional and post-translational levels by Zn stress

Aquaporins are water channel proteins that regulate plant development, growth, and response to environmental stresses. Populus trichocarpa is one of the plants with the highest number of aquaporins in its genome, but only few of them have been characterized at the whole plant functional level. Here...

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Bibliographic Details
Published in:Plant physiology and biochemistry 2019-02, Vol.135, p.588-600
Main Authors: Ariani, Andrea, Barozzi, Fabrizio, Sebastiani, Luca, di Toppi, Luigi Sanità, di Sansebastiano, Gian Pietro, Andreucci, Andrea
Format: Article
Language:English
Subjects:
Aquaporins
Aquaporins - genetics
Aquaporins - metabolism
Aquaporins - physiology
Arabidopsis
DNA, Plant - genetics
Gene Expression Regulation, Plant - drug effects
Genes, Plant - genetics
Mercury - toxicity
Phytoremediation
Plant Leaves - metabolism
Plant Leaves - physiology
Plant Proteins - genetics
Plant Proteins - metabolism
Plant Proteins - physiology
Plant Roots - metabolism
Plant Roots - physiology
Plants, Genetically Modified
Populus - drug effects
Populus - genetics
Populus - metabolism
Populus - physiology
Populus x canadensis
Post-translation modification
Protein Processing, Post-Translational
Real-Time Polymerase Chain Reaction
Zinc - toxicity
Zn stress
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Summary:Aquaporins are water channel proteins that regulate plant development, growth, and response to environmental stresses. Populus trichocarpa is one of the plants with the highest number of aquaporins in its genome, but only few of them have been characterized at the whole plant functional level. Here we analyzed a putative aquaporin gene, aqua1, a gene that encodes for a protein of 257 amino acid with the typical NPA (Asp-Pro-Ala) signature motif of the aquaporin gene family. aqua1 was down-regulated of ∼10 fold under excess Zn in both leaves and roots, and conferred Zn tolerance when expressed in yeast Zn hypersensitive strain. In vivo localization of AQUA1-GFP in Arabidopsis protoplast showed a heterogeneous distribution of this protein on different membranes destined to form aggregates related to autophagic multivesicular bodies. Zn-dependent AQUA1-GFP re-localization was perturbed by phosphatases' and kinases' inhibitors that could affect both intracellular trafficking and aquaporins' activity. Exposed to high concentration of Zn, AQUA1 also co-localized with AtTIP1;1, a well-known Arabidopsis vacuolar marker, probably in pro-vacuolar multivesicular bodies. These findings suggest that high concentration of Zn down-regulates aqua1 and causes its re-localization in new forming pro-vacuoles. This Zn-dependent re-localization appears to be mediated by mechanisms regulating intracellular trafficking and aquaporins' post-translational modifications. This functional characterization of a poplar aquaporin in response to excess Zn will be a useful reference for understanding aquaporins' roles and regulation in response to high concentration of Zn in poplar. •AQUA1 is a Hg-sensitive aquaporin.•aqua1 is regulated at transcriptional levels in response to Zn excess.•Excess Zn causes the relocalization of aqua1 in newly forming compartments.•aqua1 sub-cellular localization is regulated by post-translational modification.
ISSN:0981-9428
1873-2690
DOI:10.1016/j.plaphy.2018.10.038