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Plant Physiology 132:1518-1528 (2003) © 2003 American Society of Plant Biologists Genetic Modification of Alternative Respiration Has Differential Effects on Antimycin A-Induced versus Salicylic Acid-Induced Resistance to Tobacco mosaic virus1Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom (A.G., D.P.S., J.M.H, C.A.M., A.M.M., C.J.Y., J.S., J.P.C.)
Salicylic acid (SA), a natural defensive signal chemical, and antimycin A, a cytochrome pathway inhibitor, induce resistance to Tobacco mosaic virus (TMV). Pharmacological evidence suggested signaling during resistance induction by both chemicals involved alternative oxidase (AOX), sole component of the alternative respiratory pathway (AP). Roles of the AP include regulation of intramitochondrial reactive oxygen species and maintenance of metabolic homeostasis. Transgenic tobacco (Nicotiana tabacum) with modified AP capacities (2- to 3-fold increased or decreased) showed no alteration in phenotype with respect to basal susceptibility to TMV or the ability to display SA-induced resistance to systemic viral disease. However, in directly inoculated tissue, antimycin A-induced TMV resistance was inhibited in plants with increased AP capacities, whereas SA and antimycin A-induced resistance was transiently enhanced in plant lines with decreased AP capacities. We conclude that SA-induced TMV resistance results from activation of multiple mechanisms, a subset of which are inducible by antimycin A and influenced by AOX. Other antiviral factors, potentially including the SA-inducible RNA-dependent RNA polymerase, are regulated by AOX-independent mechanisms.
Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.102.017640. 1 This work was funded by the Biotechnology and Biological Sciences Research Council (BBSRC) with additional support from the Leverhulme Trust. J.M.H. was supported by a BBSRC Studentship. 2 These authors contributed equally to the paper. 3 Present address: CSIRO Plant Industry, Horticulture Unit, Merbein, Victoria 3505, Australia. * Corresponding author; e-mail jpc1005{at}hermes.cam.ac.uk; fax 441223333953. Received November 13, 2002; returned for revision January 21, 2003; accepted March 2, 2003. This article has been cited by other articles:
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