Functional characterization in Xenopus oocytes of Na+ transport systems from durum wheat reveals diversity among two HKT1;4 transporters. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Experimental Botany Année : 2014

Functional characterization in Xenopus oocytes of Na+ transport systems from durum wheat reveals diversity among two HKT1;4 transporters.

Résumé

Plant tolerance to salinity constraint involves complex and integrated functions including control of Na(+) uptake, translocation, and compartmentalization. Several members of the high-affinity K (+) transporter (HKT) family, which comprises plasma-membrane transporters permeable to K (+) and Na (+) or to Na (+) only, have been shown to play major roles in plant Na (+) and K (+) homeostasis. Among them, HKT1;4 has been identified as corresponding to a quantitative trait locus (QTL) of salt tolerance in wheat but was not functionally characterized. Here, we isolated two HKT1;4-type cDNAs from a salt-tolerant durum wheat (Triticum turgidum L. subsp. durum) cultivar, Om Rabia3, and investigated the functional properties of the encoded transporters using a two-electrode voltage-clamp technique, after expression in Xenopus oocytes. Both transporters displayed high selectivity for Na(+), their permeability to other monovalent cations (K (+) , Li (+) , Cs (+) , and Rb (+) ) being ten times lower than that to Na (+) . Both TdHKT1;4-1 and TdHKT1;4-2 transported Na(+) with low affinity, although the half-saturation of the conductance was observed at a Na(+) concentration four times lower in TdHKT1;4-1 than in TdHKT1;4-2. External K(+) did not inhibit Na(+) transport through these transporters. Quinine slightly inhibited TdHKT1;4-2 but not TdHKT1;4-1. Overall, these data identified TdHKT1;4 transporters as new Na(+)-selective transporters within the HKT family, displaying their own functional features. Furthermore, they showed that important differences in affinity exist among durum wheat HKT1;4 transporters. This suggests that the salt tolerance QTL involving HKT1;4 may be at least in part explained by functional variability among wheat HKT1;4-type transporters.
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hal-00936768 , version 1 (15-03-2021)

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Siwar Ben Amar, Faiçal Brini, Hervé Sentenac, Khaled Masmoudi, Anne-Aliénor Véry. Functional characterization in Xenopus oocytes of Na+ transport systems from durum wheat reveals diversity among two HKT1;4 transporters.. Journal of Experimental Botany, 2014, 65 (1), pp.213-22. ⟨10.1093/jxb/ert361⟩. ⟨hal-00936768⟩
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