A novel and conserved salt-induced protein is an important determinant of salt tolerance in yeast.
We have isolated a novel yeast gene, HAL1, which upon overexpression improves growth under salt stress. In addition, disruption of this gene decreases salt tolerance. Therefore HAL1 constitutes a rate-limiting determinant for halotolerance. It encodes a polar protein of 32 kDa located in the yeast cytoplasm and unrelated to sequences in data banks. The expression of this gene is increased by high concentrations of either NaCl, KCl or sorbitol. On the other hand, the growth advantage obtained by overexpression of HAL1 is specific for NaCl stress. In cells overexpressing HAL1, sodium toxicity seems to be counteracted by an increased accumulation of potassium. The HAL1 protein could interact with the transport systems which determine intracellular K+ homeostasis. The HAL1 gene and encoded protein are conserved in plants, being induced in these organisms by salt stress and abscisic acid. These results suggest that yeast serves as a convenient model system for the molecular biology of plant salt tolerance.
Gaxiola
R
R
European Molecular Biology Laboratory, Heidelberg, Germany.
de Larrinoa
I F
IF
Villalba
J M
JM
Serrano
R
R
D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport; D002455:Cell Division / Q000187:drug effects; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism; D004271:DNA, Fungal; D005656:Fungal Proteins / Q000096:biosynthesis / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010944:Plants / Q000187:drug effects / Q000235:genetics; D011189:Potassium Chloride / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D012492:Salts / Q000494:pharmacology*; D012689:Sequence Homology, Nucleic Acid; D012965:Sodium Chloride / Q000494:pharmacology; D013012:Sorbitol / Q000494:pharmacology
D004271:DNA, Fungal; D005656:Fungal Proteins; C076232:HAL1 protein, S cerevisiae; D047908:Intracellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D012492:Salts; D012965:Sodium Chloride; D013012:Sorbitol; D011189:Potassium Chloride