Plant natriuretic peptides are apoplastic and paracrine stress response molecules

Type
Article

Authors
Wang, Yuhua
Gehring, Christoph A
Irving, Helen R.

KAUST Department
Biological and Environmental Sciences and Engineering (BESE) Division
Bioscience Program
Molecular Signalling Group

Online Publication Date
2011-04-07

Print Publication Date
2011-05

Date
2011-04-07

Abstract
Higher plants contain biologically active proteins that are recognized by antibodies against human atrial natriuretic peptide (ANP). We identified and isolated two Arabidopsis thaliana immunoreactive plant natriuretic peptide (PNP)-encoding genes, AtPNP-A and AtPNP-B, which are distantly related members of the expansin superfamily and have a role in the regulation of homeostasis in abiotic and biotic stresses, and have shown that AtPNP-A modulates the effects of ABA on stomata. Arabidopsis PNP (PNP-A) is mainly expressed in leaf mesophyll cells, and in protoplast assays we demonstrate that it is secreted using AtPNP-A:green fluorescent protein (GFP) reporter constructs and flow cytometry. Transient reporter assays provide evidence that AtPNP-A expression is enhanced by heat, osmotica and salt, and that AtPNP-A itself can enhance its own expression, thereby generating a response signature diagnostic for paracrine action and potentially also autocrine effects. Expression of native AtPNP-A is enhanced by osmotica and transiently by salt. Although AtPNP-A expression is induced by salt and osmotica, ABA does not significantly modulate AtPNP-A levels nor does recombinant AtPNP-A affect reporter expression of the ABA-responsive RD29A gene. Together, these results provide experimental evidence that AtPNP-A is stress responsive, secreted into the apoplastic space and can enhance its own expression. Furthermore, our findings support the idea that AtPNP-A, together with ABA, is an important component in complex plant stress responses and that, much like in animals, peptide signaling molecules can create diverse and modular signals essential for growth, development and defense under rapidly changing environmental conditions. © 2011 The Author.

Citation
Wang, Y. H., Gehring, C., & Irving, H. R. (2011). Plant Natriuretic Peptides are Apoplastic and Paracrine Stress Response Molecules. Plant and Cell Physiology, 52(5), 837–850. doi:10.1093/pcp/pcr036

Acknowledgements
This work was supported by the Australian Research Council [Discovery project funding scheme (DP0557561, DP0878194)]; Australian Postgraduate Award [to Y.H.W.].

Publisher
Oxford University Press (OUP)

Journal
Plant and Cell Physiology

DOI
10.1093/pcp/pcr036

PubMed ID
21478192

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