Letters to Nature

Nature 411, 817-820 (14 June 2001) | doi:10.1038/35081107; Received 5 December 2000; Accepted 30 April 2001

Production of multiple plant hormones from a single polyprotein precursor

Gregory Pearce, Daniel S. Moura, Johannes Stratmann1 & Clarence A. Ryan

  1. Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340, USA
  2. Present address: Department of Biological Sciences, University of South Carolina, Columbia, South Carolina 29208, USA.

Correspondence to: Clarence A. Ryan Correspondence and requests for materials should be addressed to C.A.R. (e-mail: Email: cabudryan@hotmail.com). The GenBank accession number for tobacco systemin precursor pro-TobSys-A is AY033148, and for pro-TobSys-B is AY033149.

Some animal and yeast hormone genes produce prohormone polypeptides that are proteolytically processed to produce multiple copies of hormones with the same or different functions1. In plants, four polypeptides have been identified that can be classed as hormones2, 3, 4, 5 (intercellular chemical messengers6) but none are known to be produced as multiple copies from a single precursor. Here we describe a polyprotein hormone precursor, present in tobacco plants, that gives rise to two polypeptide hormones, as often found in animals and yeast. The tobacco polypeptides activate the synthesis of defensive proteinase-inhibitor proteins in a manner similar to that of systemin, an 18-amino-acid polypeptide found in tomato plants2. The two tobacco polypeptides are derived from each end of a 165-amino-acid precursor that bears no homology to tomato prosystemin. The data show that structurally diverse polypeptide hormones in different plant species can serve similar signalling roles, a condition not found in animals or yeast.