A diterpene as an endogenous signal for the activation of defense responses to infection with tobacco mosaic virus and wounding in tobacco.
In pathogen-infected or wounded tobacco plants, the activation of wound-induced protein kinase (WIPK), a tobacco mitogen-activated protein kinase, has been implicated in the defense response. However, no endogenous signal responsible for the activation has been identified. A WIPK-activating substance was isolated from tobacco leaves and identified as (11E,13E)-labda-11,13-diene-8alpha,15-diol, designated WAF-1. When applied in nanomolar concentrations to leaves, either natural WAF-1 or chemically synthesized WAF-1 activated WIPK as well as salicylic acid-induced protein kinase, a tobacco mitogen-activated protein kinase, and enhanced the accumulation of transcripts of wound- and pathogen-inducible defense-related genes. Quantitative analysis of endogenous WAF-1 revealed that levels increased rapidly in leaves during a hypersensitive response to Tobacco mosaic virus (TMV) and after wounding. Furthermore, treatment of leaves with WAF-1 resulted in enhanced resistance to TMV infection. These results suggest that WAF-1 functions as an endogenous signal to mediate the defense responses of tobacco plants to TMV infection and wounding.
Seo
Shigemi
S
Plant Physiology Department, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan.
Seto
Hideharu
H
Koshino
Hiroyuki
H
Yoshida
Shigeo
S
Ohashi
Yuko
Y
D003517:Cyclopentanes / Q000378:metabolism; D004224:Diterpenes / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D005030:Ethylenes / Q000378:metabolism; D007113:Immunity, Innate / Q000187:drug effects; D020928:Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism; D054883:Oxylipins; D010935:Plant Diseases / Q000821:virology*; D018515:Plant Leaves / Q000502:physiology / Q000821:virology; D010940:Plant Proteins; D011494:Protein Kinases / Q000096:biosynthesis; D020156:Salicylic Acid / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013314:Stress, Mechanical; D014026:Nicotiana / Q000201:enzymology / Q000502:physiology / Q000821:virology*; D014027:Tobacco Mosaic Virus / Q000254:growth & development*
D003517:Cyclopentanes; D004224:Diterpenes; D005030:Ethylenes; D054883:Oxylipins; D010940:Plant Proteins; C475161:labda-11,13-diene-8,15-diol; C011006:jasmonic acid; C036216:ethylene; D011494:Protein Kinases; D020928:Mitogen-Activated Protein Kinases; C113423:WIPK protein, Nicotiana tabacum; D020156:Salicylic Acid