Inventory and functional characterization of the HAK potassium transporters of rice.
Plant Physiol
; 130(2): 784-95, 2002 Oct.
Article
en En
| MEDLINE
| ID: mdl-12376644
Plants take up large amounts of K(+) from the soil solution and distribute it to the cells of all organs, where it fulfills important physiological functions. Transport of K(+) from the soil solution to its final destination is mediated by channels and transporters. To better understand K(+) movements in plants, we intended to characterize the function of the large KT-HAK-KUP family of transporters in rice (Oryza sativa cv Nipponbare). By searching in databases and cDNA cloning, we have identified 17 genes (OsHAK1-17) encoding transporters of this family and obtained evidence of the existence of other two genes. Phylogenetic analysis of the encoded transporters reveals a great diversity among them, and three distant transporters, OsHAK1, OsHAK7, and OsHAK10, were expressed in yeast (Saccharomyces cerevisiae) and bacterial mutants to determine their functions. The three transporters mediate K(+) influxes or effluxes, depending on the conditions of the experiment. A comparative kinetic analysis of HAK-mediated K(+) influx in yeast and in roots of K(+)-starved rice seedlings demonstrated the involvement of HAK transporters in root K(+) uptake. We discuss that all HAK transporters may mediate K(+) transport, but probably not only in the plasma membrane. Transient expression of the OsHAK10-green fluorescent protein fusion protein in living onion epidermal cells targeted this protein to the tonoplast.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Potasio
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Oryza
/
Compuestos de Selenio
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Proteínas de Transporte de Catión
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Metionina
Idioma:
En
Revista:
Plant Physiol
Año:
2002
Tipo del documento:
Article
País de afiliación:
España
Pais de publicación:
Estados Unidos