Updated publication reference for PubMed record(s): 26217812. In plants, structural and physiological evidence has suggested the presence of biologically active natriuretic peptides (PNPs). PNPs are secreted into the apoplast, are systemically mobile and elicit a range of responses signaling via cGMP. The PNP-dependent responses include tissue specific modifications of cation transport and changes in stomatal conductance and the photosynthetic rate. PNP also has a critical role in host defense responses. Surprisingly, PNP-homologues are also produced by several plant pathogens during host colonization suppressing host defense responses. Here we show that a synthetic peptide representing the biologically active fragment of the Arabidopsis thaliana PNP (AtPNP-A) induces the production of reactive oxygen species in suspension-cultured A. thaliana (Col-0) cells.