AtPep3 is a hormone-like peptide that plays a role in the salinity stress tolerance of plants

Significance Hormone-like peptides derived from small coding genes (<100 amino acids) have not been extensively characterized in relation to abiotic stress tolerance. Focusing on 17 salinity stress-inducible small coding genes in Arabidopsis , we showed that four genes conferred increased salinity stress tolerance when overexpressed in transgenic plants. One of the four genes ( AtPROPEP3 ) was found to induce salinity stress tolerance by treatment with a 13-peptide (KPTPSSGKGGKHN) fragment, providing unique functional evidence for enhanced salinity stress tolerance in plants in response to a peptide treatment. Although the 13-peptide fragment shares homology with known peptides associated with immune response, the other peptides may encode unique hormone-like peptides associated with salinity stress tolerance.