|Singh, Ajay - RUTGERS UNIVERSITY|
|Canas, Luis - OHIO STATE UNIVERSITY|
|Vorsa, Nicholi - RUTGERS UNIVERSITY|
Submitted to: National Meeting of Entomological Society Of America
Publication Type: Abstract Only
Publication Acceptance Date: July 1, 2007
Publication Date: December 9, 2007
Citation: Ranger, C.M., Singh, A.P., Frantz, J., Canas, L., Locke, J.C., Vorsa, N., Reding, M.E. Silicon-inducible defenses of Zinnia elegans against Myzus persicae. National Meeting of Entomological Society Of America.Available: http://esa.confex.com/esa/2007/techprogram/paper_28624.htm Technical Abstract: Several examples exist of silicon (Si) amendment inducing plant chemical defenses against plant pathogens, but few studies have focused on Si-induced defenses against phloem-feeding herbivores. The current study examined Si treatment of Zinnia elegans Jacq. cv. Oklahoma White (Compositae) on the performance and population fitness of Myzus persicae (Sulzer) (Hemiptera: Aphididae), along with the induction of defense-related phenolics. Zinnia elegans plants were irrigated with a nutrient solution amended with potassium silicate, K2SiO2, (Si+); a nutrient solution without K2SiO2, (Si-); or deionized water only (DI). Length of the prereproductive period and survivorship of M. persicae were not affected by Si treatment, but total cumulative fecundity and the intrinsic rate of increase (rm) were significantly lower on Si+ vs. Si- plants. Overall, M. persicae exhibited the poorest performance and population fitness on DI plants. HPLC-MS identification and quantification of phenolics determined a dihydroxycinnamoyl amide conjugate and several flavonols were elevated in Si+ vs. Si- plants, but the greatest degree of induction occurred in DI plants. These results document a reduction in M. persicae population fitness and an elevation in phenolics by treatment of Z. elegans with soluble Si. However, the absence of nutrients provided to DI plants had a greater influence on elevating phenolics and resistance of Z. elegans to M. persicae. Resistance associated with Si+ and DI plants may be attributed more to chemical, than physical, mechanisms.