Plant Biol (Stuttg) 2000; 2(1): 1-3
DOI: 10.1055/s-2000-9147
Rapid Communication
Georg Thieme Verlag Stuttgart ·New York

In Situ and in Vitro Binding of Natriuretic Peptide Hormones in Tradescantia multiflora

I. N. Suwastika 1 , T. Toop 2 , H. R. Irving 3 , C. A. Gehring 2
  • 1 Present address: Basic Sciences Department, Faculty of Agriculture, Tadulako University, Palu 94118, Indonesia
  • 2 Deakin University, School of Biological and Chemical Sciences, Geelong, Victoria 3217, Australia
  • 3 Department of Pharmaceutical Biology and Pharmacology, Victorian College of Pharmacy, Monash University, Parkville, Melbourne, Victoria 3052, Australia
Further Information

Publication History

June 18, 1999

November 9, 1999

Publication Date:
31 December 2000 (online)

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Abstract:

An increasing body of evidence suggests that in plants, as in vertebrates, biologically active natriuretic peptide (NP) hormones play an important role in the regulation of the osmotic and ionic balance. The evidence includes isolation and immunoaffinity purification of biologically active natriuretic peptide analogues (irPNP) from ivy that promoted stomatal opening and specifically, rapidly and transiently increased cGMP levels in root conductive tissue. In this study we demonstrate that I125-rat atrial natriuretic peptide (rANP) binds to plasma membranes from leaf and stem tissue of Tradescantia multiflora and importantly, both unlabelled rANP and irPNP can competitively displace that binding. In addition, tissue section autoradiography reveals specific in situ binding of I125-rANP to leaf and stem tissue. The findings are consistent with the presence of a biologically active NP system in plants and suggest that NPs signal through a dedicated receptor system.

Abbreviations:

ANP: atrial natriuretic peptide IB: incubation buffer irPNP: biologically active plant natriuretic peptide analogues NP: natriuretic peptide rANP: rat ANP