TY - JOUR
T1 - Inhibition of baculoviral disease by plant-mediated peroxidase activity and free radical generation
AU - Hoover, Kelli
AU - Kishida, Kenneth T.
AU - Digiorgio, Louis A.
AU - Workman, Jeff
AU - Alaniz, Susan A.
AU - Hammock, Bruce D.
AU - Duffey, Sean S.
N1 - Funding Information:
contributions, perserverance, and inspirational guidance, this work would not have been possible. This research was supported in part by E. I. DuPont De Nemours & Co., USDA Competitive Research Grants Program, 94-37302-0567; US/Israel BARD IS-2530-95C; UC Systemwide Biotechnology Research and Education Program; NSF DMS 95-10511 Center for Statistics in Science & Technology Group; Jastro-Shields Research Fellowships, and the Departments of Entomology and UCD Graduate Studies for travel grants. K. H. was supported by a fellowship from Novo-Nordisk Entotech. We thank A. L. Tappel for consultation on the heme assay for free radicals and D. E. Ullman for the loan of her leaf press machine. Thanks to J. M. Legac, C. Baon, and Y. Tam for technical support. We also thank G. W. Felton, R. M. Bostock, and M. J. Stout for valuable discussions concerning this work and/or critical review of the manuscript. The University of California-Davis is a NIH Environmental Health Sciences Center, P30 ESO5707 and a U.S. EPA Center for Ecological Health Research, CR819658.
PY - 1998
Y1 - 1998
N2 - The susceptibility of noctuid larvae to baculoviral infection is markedly affected by phytochemicals ingested during the acquisition of vital inoculum on foliage. We hypothesized that a major process causing phytochemical inhibition of viral disease is phenolic oxidation by phenolases, particularly peroxidase (POD), which subsequently generates free radicals. To test this hypothesis, we manipulated the chemical interactions in foliage of cotton, tomato, and lettuce by application of antioxidants, prooxidants, enriched extracts of phenolases, and/or phenolic substrates. Larvae of Heliothis virescens or Helicoverpa zea that received viral inoculum on treated foliage were less likely to die from viral infection the higher the POD activity of this foliage. Furthermore, the higher the POD activity, the more free radicals were generated in crushed foliage, and the more free radicals generated, the lower the incidence of viral disease. We present a series of reactions hypothesized to lead to inhibition of viral disease by free radicals, the generation of which is mediated, at least in part, by POD. Phenolic redox cycling catalyzed by POD involving clastogenesis (generation of H2O2) appeared to be a critical driver of phytochemical reactions leading to free radical generation and inhibition of baculoviral disease in their noctuid hosts. We also report application of an assay for the detection of free radicals by using methemoglobin as a new modification of this method for detecting radicals in plant foliage in the immediate aftermath of an oxidative burst.
AB - The susceptibility of noctuid larvae to baculoviral infection is markedly affected by phytochemicals ingested during the acquisition of vital inoculum on foliage. We hypothesized that a major process causing phytochemical inhibition of viral disease is phenolic oxidation by phenolases, particularly peroxidase (POD), which subsequently generates free radicals. To test this hypothesis, we manipulated the chemical interactions in foliage of cotton, tomato, and lettuce by application of antioxidants, prooxidants, enriched extracts of phenolases, and/or phenolic substrates. Larvae of Heliothis virescens or Helicoverpa zea that received viral inoculum on treated foliage were less likely to die from viral infection the higher the POD activity of this foliage. Furthermore, the higher the POD activity, the more free radicals were generated in crushed foliage, and the more free radicals generated, the lower the incidence of viral disease. We present a series of reactions hypothesized to lead to inhibition of viral disease by free radicals, the generation of which is mediated, at least in part, by POD. Phenolic redox cycling catalyzed by POD involving clastogenesis (generation of H2O2) appeared to be a critical driver of phytochemical reactions leading to free radical generation and inhibition of baculoviral disease in their noctuid hosts. We also report application of an assay for the detection of free radicals by using methemoglobin as a new modification of this method for detecting radicals in plant foliage in the immediate aftermath of an oxidative burst.
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U2 - 10.1023/A:1020777407980
DO - 10.1023/A:1020777407980
M3 - Article
AN - SCOPUS:0032427508
SN - 0098-0331
VL - 24
SP - 1949
EP - 2001
JO - Journal of Chemical Ecology
JF - Journal of Chemical Ecology
IS - 12
ER -