Plant natriuretic peptide homologues?

Helen R Irving, in association with Dr D. Cahill, School of Biological and Chemical Sciences, Deakin University, and Prof CA Gehring, University of the Western Cape.

Natriuretic peptides are a family of peptides strongly implicated in the regulation of salt and water homeostasis in animals. Antibodies to atrial natriuretic peptide have been used to immunoaffinity purify a plant homologue from ivy leaves. Both atrial natriuretic peptide and the plant homologues are active in plant tissue where they stimulate stomatal opening and increases in cyclic GMP (Pharmawati et al. (1998) Plant Sci. 137: 107-115; Pharmawati et al. (2001) Plant Physiol Biochem 39: 1-10).

We have identified plant homologues to the plant natriuretic peptides by protein and DNA sequencing studies using homology database searches. We are expressing these plant homologues in bacteria. The aim of this project is to test if this recombinant protein(s) contains plant natriuretic peptide activity. The project will involve a range of biochemical and plant physiology techniques.