LAUSR

Marine algae survive in a high sodium environment, however, they experience potassium deprivation in cells as a consequence. Our previous study demonstrated that genes from the marine species of macroalgae, Pyropia yezoensis, including the ammonium transporter, PyAMT1, and a β-carbonic anhydrase, PyβCA1, could complement a potassium-uptake defective Escherichia coli mutant. In the present study, various Pyropia genes were expressed in Arabidopsis to determine if Pyropia genes could enhance potassium-deficiency tolerance in plants. Overexpression of PyAMT1, a nitrate transporter, PyNRT2.1, PyβCA1, and their Arabidopsis homologs in Arabidopsis, enhanced the tolerance of the transgenic plants to potassium starvation without altering potassium levels in the plants. A Pyropia coatomer gene, which is similar to the Arabidopsis coat protein complex I zeta subunit, also contributed to enhancing potassium deficiency tolerance and increasing potassium accumulation in Arabidopsis. The Pyropia PyC5 gene does not have any known homologues in higher plants and lacks any known motifs or domains. PyC5-overexpressing Arabidopsis plants grew much better under potassium deficiency conditions compared to control plants. Collectively, the results suggest that marine algae genes could be used as a novel source of genes to aid in the development of stress-tolerant plants.