Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

Evidence for long-distance xylem transport of signal peptide activity from tomato roots

Peter M. Neumann
Journal of Experimental Botany
Vol. 58, No. 8 (2007), pp. 2217-2223
Published by: Oxford University Press
Stable URL: http://www.jstor.org/stable/24036807
Page Count: 7
  • Download ($42.00)
  • Cite this Item
Evidence for long-distance xylem transport of signal peptide activity from tomato roots
Preview not available

Abstract

Several types of small, endogenous signal peptides are now known to induce a wide range of local and systemic responses in plants, but how such signal peptide activity is transported over long distances remains unclear. In particular, the possible occurrence and root-to-shoot transport of signal peptide activity in the xylem does not appear to have been previously investigated. Suspension-cultured cells of wild tomato Lycopersicon peruvanium L. were used in an established bioassay for detecting nanomolar concentrations of signal peptides via the induction of alkalinizing activity. Xylem sap naturally exuded from the cut and washed stem-surfaces of de-topped tomato plants (Lycopersicon esculentum L. cv. Castlemart) was collected, partially purified, concentrated, and shown by the bioassay consistently to contain significant alkalinizing activity. Plant salinity treatment induced further small increases in activity. Subsidiary experiments indicated that the alkalinizing activity found in the xylem-sap had properties similar to those of known plant signal peptides and was root derived. Thus, it was (i) detectable within minutes, (ii) eluted similarly during HPLC chromatography, (iii) destroyed by incubation with proteases and stable in the presence of protease inhibitor cocktail, and (iv) not found in bioassays of simulated xylem sap placed on the cut stemsurfaces of non-exuding roots in order to detect any significant release of wound peptides from the stem. Further investigations of the signal peptide activity in root xylem sap could provide new insights into its identity, genes, receptors, origins, and possible hormonal roles in regulating shoot growth and development.

Page Thumbnails

  • Thumbnail: Page 
[2217]
    [2217]
  • Thumbnail: Page 
2218
    2218
  • Thumbnail: Page 
2219
    2219
  • Thumbnail: Page 
2220
    2220
  • Thumbnail: Page 
2221
    2221
  • Thumbnail: Page 
2222
    2222
  • Thumbnail: Page 
2223
    2223