Distinct Functions of the Atypical Terminal Hydrophilic Domain of the HKT Transporter in the Liverwort Marchantia polymorpha

Autor: Shahin Imran, Masumi Oyama, Rie Horie, Natsuko I Kobayashi, Alex Costa, Ryosuke Kumano, Chiho Hirata, Sen Thi Huong Tran, Maki Katsuhara, Keitaro Tanoi, Takayuki Kohchi, Kimitsune Ishizaki, Tomoaki Horie
Rok vydání: 2022
Předmět:
Zdroj: Plant and Cell Physiology (2022). doi:10.1093/pcp/pcac044
info:cnr-pdr/source/autori:Imran, S (Imran, Shahin) [1], [2] ; Oyama, M (Oyama, Masumi) [3] ; Horie, R (Horie, Rie) [3] ; Kobayashi, NI (Kobayashi, Natsuko, I) [4] ; Costa, A (Costa, Alex) [5], [6] ; Kumano, R (Kumano, Ryosuke) [3] ; Hirata, C (Hirata, Chiho) [7] ; Tran, STH (Sen Thi Huong Tran) [1], [8] ; Katsuhara, M (Katsuhara, Maki) [1] ; Tanoi, K (Tanoi, Keitaro) [4] ; Kohchi, T (Kohchi, Takayuki) [9] ; Ishizaki, K (Ishizaki, Kimitsune) [7] ; Horie, T (Horie, Tomoaki) [3]/titolo:Distinct Functions of the Atypical Terminal Hydrophilic Domain of the HKT Transporter in the Liverwort Marchantia polymorpha/doi:10.1093%2Fpcp%2Fpcac044/rivista:Plant and Cell Physiology/anno:2022/pagina_da:/pagina_a:/intervallo_pagine:/volume
ISSN: 1471-9053
0032-0781
DOI: 10.1093/pcp/pcac044
Popis: K+/Na+ homeostasis is important for land plants, particularly under salt stress. In this study, the structure and ion transport properties of the high-affinity K+ transporter (HKT) of the liverwort Marchantia polymorpha were investigated. Only one HKT gene, MpHKT1, was identified in the genome of M. polymorpha. Phylogenetic analysis of HKT proteins revealed that non-seed plants possess HKTs grouped into a clade independent of the other two clades including HKTs of angiosperms. A distinct long hydrophilic domain was found in the C-terminus of MpHKT1. Complementary DNA (cDNA) of truncated MpHKT1 (t-MpHKT1) encoding the MpHKT_Δ596-812 protein was used to examine the functions of the C-terminal domain. Both MpHKT1 transporters fused with enhanced green fluorescent protein at the N-terminus were localized to the plasma membrane when expressed in rice protoplasts. Two-electrode voltage clamp experiments using Xenopus laevis oocytes indicated that MpHKT1 mediated the transport of monovalent alkali cations with higher selectivity for Na+ and K+, but truncation of the C-terminal domain significantly reduced the transport activity with a decrease in the Na+ permeability. Overexpression of MpHKT1 or t-MpHKT1 in M. polymorpha conferred accumulation of higher Na+ levels and showed higher Na+ uptake rates, compared to those of wild-type plants; however, phenotypes with t-MpHKT1 were consistently weaker than those with MpHKT1. Together, these findings suggest that the hydrophilic C-terminal domain plays a unique role in the regulation of transport activity and ion selectivity of MpHKT1.
Databáze: OpenAIRE
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