Abstract
In the previous reports, we have shown that PMP3, a membrane protein, can alleviate NaCl-induced growth suppression via reducing Na+ uptake into the shoots in Arabidopsis and rice plants. In this report, we analyzed the function of yeast and rice PMP3 proteins in the cellular ion homeostasis. The wild type yeast and Δpmp3 mutant, which has a disruption in the PMP3 gene, were complemented with pYES2, PMP3-pYES2 and OsPMP3-3-pYES2. The phenotype of yeast mutants grown under treatment of various chemicals could be divided to 4 groups, 1) Δpmp3 was more sensitive, 2) Δpmp3 was more tolerant, 3) Δpmp3+PMP3-pYES2 was more sensitive, and 4) comparable among all lines. Interestingly, Δpmp3 mutants were more sensitive to heat stress than wild type. These results suggest that yeast and rice PMP3 might contribute to maintaining the cellular ionic homeostasis via directly or indirectly regulating proton influx.
