title: Plant natriuretic peptides induce proteins diagnostic for an adaptive response to stress.
abstract: 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-homologs are 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. To identify proteins whose expression changes in an AtPNP-A dependent manner, we undertook a quantitative proteomic approach, employing tandem mass tag (TMT) labeling, to reveal temporal responses of suspension-cultured cells to 1 nM and 10 pM PNP at two different time-points post-treatment. Both concentrations yield a distinct differential proteome signature. Since only the higher (1 nM) concentration induces a ROS response, we conclude that the proteome response at the lower concentration reflects a ROS independent response. Furthermore, treatment with 1 nM PNP results in an over-representation of the gene ontology (GO) terms "oxidation-reduction process," "translation" and "response to salt stress" and this is consistent with a role of AtPNP-A in the adaptation to environmental stress conditions.
authors.affiliation: Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology Thuwal, Saudi Arabia.
authors.forename: Ilona
authors.initials: I
authors.lastname: Turek
authors.affiliation: Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology Thuwal, Saudi Arabia.
authors.forename: Claudius
authors.initials: C
authors.lastname: Marondedze
authors.affiliation: Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University Melbourne, VIC, Australia.
authors.forename: Janet I
authors.initials: JI
authors.lastname: Wheeler
authors.affiliation: Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology Thuwal, Saudi Arabia.
authors.forename: Chris
authors.initials: C
authors.lastname: Gehring
authors.affiliation: Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University Melbourne, VIC, Australia.
authors.forename: Helen R
authors.initials: HR
authors.lastname: Irving
keywords: molecular mimicry; peptide hormone signaling; plant homeostasis; plant natriuretic peptide; reactive oxygen species; salt stress