The octadecanoid signalling pathway in plants mediates a response to ultraviolet radiation.
Many plant genes that respond to environmental and developmental changes are regulated by jasmonic acid, which is derived from linolenic acid via the octadecanoid pathway. Linolenic acid is an important fatty-acid constituent of membranes in most plant species and its intracellular levels increase in response to certain signals. Here we report that irradiation of tomato leaves with ultraviolet light induces the expression of several plant defensive genes that are normally activated through the octadecanoid pathway after wounding. The response to ultraviolet light is blocked by an inhibitor of the octadecanoid pathway and it does not occur in a tomato mutant defective in this pathway. The ultraviolet irradiation maximally induces the defence genes at levels where cyclobutane pyrimidine dimer formation, an indicator of DNA damage, is less than 0.2 dimers per gene. Our evidence indicates that this plant defence response to certain wavelengths of ultraviolet radiation requires the activation of the octadecanoid defence signalling pathway.
Institute of Biological Chemistry, Washington State University, Pullman 99164, USA.
A
A
Conconi
M J
MJ
Smerdon
G A
GA
Howe
C A
CA
Ryan
D003517:Cyclopentanes / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects*; D018551:Solanum lycopersicum / Q000235:genetics / Q000528:radiation effects*; D054883:Oxylipins; D018515:Plant Leaves / Q000528:radiation effects; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011480:Protease Inhibitors / Q000528:radiation effects; D011740:Pyrimidine Dimers; D012459:Salicylates / Q000494:pharmacology; D020156:Salicylic Acid; D015398:Signal Transduction; D013229:Stearic Acids / Q000378:metabolism; D014466:Ultraviolet Rays; D017962:alpha-Linolenic Acid / Q000378:metabolism
D003517:Cyclopentanes; D004791:Enzyme Inhibitors; D054883:Oxylipins; D010940:Plant Proteins; D011480:Protease Inhibitors; D011740:Pyrimidine Dimers; D012459:Salicylates; D013229:Stearic Acids; C034104:proteinase inhibitor II protein, plant; D017962:alpha-Linolenic Acid; C023578:proteinase inhibitor I (plants); C011006:jasmonic acid; D020156:Salicylic Acid