Gene Details:

• MSU gene ID: LOC_Os06g48800
• RAPdb gene ID: Os06g0701600
• Gene Symbol: OsHKT2 4
• Genome: MSU7 ,  IRGSP-1.0
• Species: Oryza sativa

Functional Descriptions:

• OsHKT2;4 rescued the growth defect of a K(+) uptake-deficient yeast mutant.
• The HKT rice gene, named OsHKT2;4, is expressed in several cell types, including root hairs and vascular parenchyma cells.
• The genetically tractable rice (Oryza sativa; background Nipponbare) possesses two predicted K(+)-transporting class II HKT transporter genes, OsHKT2;3 and OsHKT2;4.
• In this study, we have characterized the ion selectivity of the class II rice HKT transporter OsHKT2;4 in yeast and Xenopus laevis oocytes.
• Interestingly, however, K(+) influx in OsHKT2;4-expressing oocytes did not require stimulation by extracellular Na(+), in contrast to other class II HKT transporters.
• Comparative analyses of Ca(2+) and Mg(2+) permeabilities in several HKT transporters, including Arabidopsis thaliana HKT1;1 (AtHKT1;1), Triticum aestivum HKT2;1 (TaHKT2;1), OsHKT2;1, OsHKT2;2, and OsHKT2;4, revealed that only OsHKT2;4 and to a lesser degree TaHKT2;1 mediate Mg(2+) transport.
• Interestingly, cation competition analyses demonstrate that the selectivity of both of these class II HKT transporters for K(+) is dominant over divalent cations, suggesting that Mg(2+) and Ca(2+) transport via OsHKT2;4 may be small and would depend on competing K(+) concentrations in plants.
• K+ transport by the OsHKT2;4 transporter from rice with atypical Na+ transport properties and competition in permeation of K+ over Mg2+ and Ca2+ ions.
• Surprisingly, a subfamily 2 member from rice (Oryza sativa), OsHKT2;4, has been proposed to form cation/K(+) channels or transporters permeable to Ca(2+) when expressed in Xenopus oocytes.
• Further analyses in media containing both Na(+) and K(+) indicated that OsHKT2;4 functions as K(+)-selective transporter at low external Na(+), but transports also Na(+) at high (>10 mm) Na(+) concentrations.
• These data identify OsHKT2;4 as a new functional type in the K(+) and Na(+)-permeable HKT transporter subfamily.
• The rice monovalent cation transporter OsHKT2;4: revisited ionic selectivity.
• laevis oocytes, we found that OsHKT2;4 could rescue the growth of MM281 in Mg(2+)-deficient conditions and induced the Mg(2+) currents in oocytes at millimolar range of Mg(2+).
• The Rice High-Affinity K(+) Transporter OsHKT2;4 Mediates Mg(2+) Homeostasis under High-Mg(2+) Conditions in Transgenic Arabidopsis.
• Additionally, overexpression of OsHKT2;4 to Arabidopsis mutant lines with a knockout of AtMGT6, a gene encoding the transporter protein necessary for Mg(2+) adaptation in Arabidopsis, caused the Mg(2+) toxicity to the leaves under the high-Mg(2+) stress, but not under low-Mg(2+) environments.
• Together, our results demonstrated that OsHKT2;4 is a low-affinity Mg(2+) transporter responsible for Mg(2+) transport to aerials in plants under high-Mg(2+) conditions.

Function-related keywords:

• growth ,  root ,  transporter ,  root-hair ,  homeostasis ,  R-protein

Literature:

• K+ transport by the OsHKT2;4 transporter from rice with atypical Na+ transport properties and competition in permeation of K+ over Mg2+ and Ca2+ ions .  DOI:  10.1104/pp.110.168047 ;  PMID:  21610181
• The rice monovalent cation transporter OsHKT2;4: revisited ionic selectivity .  DOI:  10.1104/pp.112.194936 ;  PMID:  22773759
• A rice high-affinity potassium transporter (HKT) conceals a calcium-permeable cation channel .  DOI:  10.1073/pnas.1000698107 ;  PMID:  20351263
• The Rice High-Affinity K+ Transporter OsHKT2;4 Mediates Mg2+ Homeostasis under High-Mg2+ Conditions in Transgenic Arabidopsis .  DOI:  10.3389/fpls.2017.01823 ;  PMID:  29114257

Related News:

Gene Resources:

• NCBI ID: AJ491855
• UniProt accessions:

Sequences: