Sugar beet cold-induced PMT5a and STP13 carriers are poised for taproot proton-driven plasma membrane sucrose and glucose import - Institut des sciences des plantes de Montpellier Accéder directement au contenu
Pré-Publication, Document De Travail Année : 2022

Sugar beet cold-induced PMT5a and STP13 carriers are poised for taproot proton-driven plasma membrane sucrose and glucose import

Dawid Jaślan
Khaled a S Al-Rasheid
Ahmed H Alfarhan
Saleh A Alquraishy
Frank Ludewig
Wolfgang Koch
Karsten Harms

Résumé

• As the major sugar-producing crop in the northern hemisphere, sugar beet taproots store sucrose at a concentration of about 20 %. While the vacuolar sucrose loader TST has already been identified in the taproot, sugar transporters mediating sucrose uptake across the plasma membrane of taproot parenchyma cells remained unknown. • We electrophysiologically examined taproots for proton-coupled sugar uptake and identified potentially involved transporters by transcriptomic profiling. After cloning, the transporter features were studied in the heterologous Xenopus laevis oocyte expression system using the two-electrode voltage clamp technique. Insights into the structure were gained by 3D homology modeling. • As with glucose, sucrose stimulation of taproot parenchyma cells caused inward H+-fluxes and plasma membrane depolarization, indicating a sugar/proton symport mechanism. As one potential candidate for sugar uploading, the BvPMT5a was characterized as a H+-driven low-affinity glucose transporter, which does not transport sucrose. BvSTP13 operated as a high-affinity H+/sugar symporter, transporting glucose and to some extent sucrose due to a binding cleft plasticity. Both transporter genes were upregulated upon cold exposure, with the transport capacity of BvSTP13 being more cold-resistant than BvPMT5a. • Identification of BvPMT5a and BvSTP13 as taproot sugar transporters could improve 43 breeding of cold-tolerant sugar beet to provide a sustainable energy crop.
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Dates et versions

hal-03842350 , version 1 (07-11-2022)

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Paternité

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Antonella Reyer, Nadia Bazihizina, Sönke Scherzer, Justyna Jaślan, Nadine Schäfer, et al.. Sugar beet cold-induced PMT5a and STP13 carriers are poised for taproot proton-driven plasma membrane sucrose and glucose import. 2022. ⟨hal-03842350⟩
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