Induced tolerance of neonate Heliothis zea to host plant allelochemicals and carbaryl following incubation of eggs on foliage of Lycopersicon hirsutum f. glabratum

Abstract

Incubation of Heliothis zea (Boddie) eggs on foliage of Lycopersicon hirsutum f. glabratum C.H. Mull (accession PI 134417) results in neonates with elevated levels of tolerance to the toxic effects of PI 134417 foliage attributable to 2-tridecanone found in the glandular trichomes which abound on that foliage. The neonates from such eggs are also shown to have elevated levels of tolerance to the carbamate insecticide carbaryl. Incubation of eggs in an atmosphere containing 2-tridecanone similarly produced elevated levels of tolerance to 2-tridecanone among resulting neonates, indicating that 2-tridecanone is the likely inducing agent and that exposure to 2-tridecanone vapor, which is known to emanate from PI 134417 foliage, is sufficient for induction. Analysis of the cytochrome P-450 content in gut microsomes of fifth instar larvae indicated that exposure of larvae to 2-tridecanone in artificial diet or to PI 134417 foliage resulted in significantly elevated levels of cytochrome P-450 relative to larvae fed diet without 2-tridecanone or foliage of L. esculentum which contains no 2-tridecanone. In addition, removal of the glandular trichomes from PI 134417 foliage eliminated the ability of that foliage to induce elevated levels of cytochrome P-450. These results provide circumstantial evidence that cytochrome P-450 may be involved in the induced tolerance to xenobiotics among neonates from eggs exposed to 2-tridecanone or PI 134417 foliage.

Genetic Improvement of Tomato

“…(Kennedy 1984;Riskallah et al 1986a,b;Kennedy et al 1987a). 2-Tridecanone evidently induces detoxifying enzymes, probably mixed function oxidases, in Heliothis spp.…”

“…has been reported in all of these plant species. In many cases, however, resistance factors are present in the foliage (e.g., Farrar and Kennedy 1987a;this Vol.). Heliothis spp.…”

“…2-Tridecanone evidently induces detoxifying enzymes, probably mixed function oxidases, in Heliothis spp. H. zea larvae which recover from their initial intoxication, or hatch from eggs exposed to 2-tridecanone, show increased tolerance to 2-tridecanone and certain insecticides (Kennedy 1984;Kennedy et al 1987a). Kennedyet al (1987a) also found that this induction occurs if H. zea is exposed to 2-tridecanone in the egg stage.…”

“…In L. hirsutum f. glabratum, PI 134417, there are as yet unidentified factors associated with the leaf lamella which cause increased mortality, reduced growth, and reduced feeding rates in H. zea larvae (Farrar and Kennedy 1987a). The genetics of these factors is not well known.…”

Developmental variation in cytochrome P450 expression in Papilio polyxenes in response to xanthotoxin, a hostplant allelochemical

“…Kennedy et al (1987) demonstrated that tolerance to volatile 2-tridecanone in the egg stage of Helicoverpa zea results in elevated levels of tolerance to the compound in newly hatched larvae. Although the mechanism of detoxification in this system is inferred, and not demonstrated, to be P450-related, the findings suggest that induced tolerance to allelochemicals may be critical to survival even before feeding begins.…”