« Previous AbstractLeaf wound induced ultraweak photon emission is suppressed under anoxic stress: Observations of Spathiphyllum under aerobic and anaerobic conditions using novel in vivo methodology    Next AbstractMedicago truncatula increases its iron-uptake mechanisms in response to volatile organic compounds produced by Sinorhizobium meliloti »

Proc Natl Acad Sci U S A

Title:		Hydrogen peroxide is generated systemically in plant leaves by wounding and systemin via the octadecanoid pathway
Author(s):		Orozco-Cardenas M; Ryan CA;
Address:		"Institute of Biological Chemistry, Washington State University, Pullman, WA 99163-6340, USA"
Journal Title:		Proc Natl Acad Sci U S A
Year:		1999
Volume:		96
Issue:		11
Page Number:		6553 - 6557
DOI:		10.1073/pnas.96.11.6553
ISSN/ISBN:		0027-8424 (Print) 1091-6490 (Electronic) 0027-8424 (Linking)
Abstract:		"Hydrogen peroxide (H2O2) generated in response to wounding can be detected at wound sites and in distal leaf veins within 1 hr after wounding. The response is systemic and maximizes at about 4-6 hr in both wounded and unwounded leaves, and then declines. The timing of the response corresponds with an increase in wound-inducible polygalacturonase (PG) mRNA and enzyme activity previously reported, suggesting that oligogalacturonic acid (OGA) fragments produced by PG are triggering the H2O2 response. Systemin, OGA, chitosan, and methyl jasmonate (MJ) all induce the accumulation of H2O2 in leaves. Tomato plants transformed with an antisense prosystemin gene produce neither PG activity or H2O2 in leaves in response to wounding, implicating systemin as a primary wound signal. The antisense plants do produce both PG activity and H2O2 when supplied with systemin, OGA, chitosan, or MJ. A mutant tomato line compromised in the octadecanoid pathway does not exhibit PG activity or H2O2 in response to wounding, systemin, OGA, or chitosan, but does respond to MJ, indicating that the generation of H2O2 requires a functional octadecanoid signaling pathway. Among 18 plant species from six families that were assayed for wound-inducible PG activity and H2O2 generation, 14 species exhibited both wound-inducible PG activity and the generation of H2O2. Four species, all from the Fabaceae family, exhibited little or no wound-inducible PG activity and did not generate H2O2. The time course of wound-inducible PG activity and H2O2 in Arabidopsis thaliana leaves was similar to that found in tomato. The cumulative data suggest that systemic wound signals that induce PG activity and H2O2 are widespread in the plant kingdom and that the response may be associated with the defense of plants against both herbivores and pathogens"
Keywords:		"Hydrogen Peroxide/*metabolism Oligodeoxyribonucleotides, Antisense/pharmacology Peptides/genetics/*metabolism Plant Leaves/drug effects/metabolism Plant Proteins/metabolism Plants/genetics/*metabolism Plants, Edible/metabolism Polygalacturonase/genetics/*;"
Notes:		"MedlineOrozco-Cardenas, M Ryan, C A eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. 1999/05/26 Proc Natl Acad Sci U S A. 1999 May 25; 96(11):6553-7. doi: 10.1073/pnas.96.11.6553"