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Medium-Chain Polyprenols Influence Chloroplast Membrane Dynamics In Solanum Lycopersicum

Van Gelder, Kristen and Rea, Kevin A. and Virta, Lilia K.A. and Whitnell, Kenna L. and Osborn, Michael and Vatta, Maritza and Khozin, Alexandra and Skorupinska-Tudek, Karolina and Surmacz, Liliana and Akhtar, Tariq A. (2018) Medium-Chain Polyprenols Influence Chloroplast Membrane Dynamics In Solanum Lycopersicum. Plant and Cell Physiology, 59 (11). 2350 -2365. ISSN 1471-9053 (online)

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Official URL: https://academic.oup.com/pcp/article/59/11/2350/50...

Abstract

The widespread occurrence of polyprenols throughout the plant kingdom is well documented, yet their functional role is poorly understood. These lipophilic compounds are known to be assembled from isoprenoid precursors by a class of enzymes designated as cisprenyltransferases (CPTs), which are encoded by small CPT gene families in plants. In this study, we report that RNAi-mediated knockdown of one member of the tomato CPT family (SlCPT5) reduced polyprenols in leaves by ~70%. Assays with recombinant SlCPT5 produced in E. coli determined that the enzyme synthesizes polyprenols of approximately 50-55 carbons (Pren-10, Pren-11) in length and accommodates a variety of trans-prenyldiphosphate precursors as substrates. Introduction of SlCPT5 into the polyprenol-deficient yeast Δrer2 mutant resulted in the accumulation of Pren-11 in yeast cells, restored proper protein Nglycosylation, and rescued the temperature sensitive growth phenotype that is associated with its polyprenol deficiency. Subcellular fractionation studies together with in vivo localization of SlCPT5 fluorescent protein fusions demonstrated that SlCPT5 resides in the chloroplast stroma and that its enzymatic products accumulate into both thylakoid and envelope membranes. Transmission electron microscopy images of polyprenol-deficient leaves revealed alterations in chloroplast ultrastructure and anisotropy measurements revealed a more disordered state of their envelope membranes. In polyprenol-deficient leaves, CO2 assimilation was hindered and their thylakoid membranes exhibited lower phase transition temperatures and calorimetric enthalpies, which coincided with a decreased photosynthetic electron transport rate. Taken together, these results uncover a role for polyprenols in governing chloroplast membrane dynamics.

Item Type:Article
Uncontrolled Keywords:Polyprenol, cis-prenyltransferase, Solanum lycopersicum, membrane fluidity, photosynthesis,chloroplast envelope
Subjects:Q Science > QH Natural history > QH301 Biology
Divisions:Department of Lipid Biochemistry
ID Code:1613
Deposited By: dr Liliana Surmacz
Deposited On:09 Nov 2018 08:31
Last Modified:08 Sep 2019 22:05

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