Indiscrimination of Manduca sexta larvae to overexpressed and underexpressed levels of phenylalanine ammonia-lyase in tobacco leaves

H. Eichenseer, J. L. Bi, G. W. Felton

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

Manduca sexta (L.) larvae were unable to discriminate between transgenic tobacco leaves expressing high or low levels of phenylalanine ammonia-lyase (PAL) in dual choice arenas. Tobacco leaves overexpressing PAL had up to ten times more chlorogenic acid and up to twice as much rutin in their leaves than leaves containing the same sense-suppressed gene. Caterpillars reared previously on artificial diet or tobacco leaves had no preference for either leaves over- or underexpressing PAL. Application of exogenous chlorogenic acid to PAL-suppressed leaves at levels similar to the overexpressed leaves did not affect M. sexta's choice. When applied at higher rates, treated leaves were preferred by caterpillars reared on tobacco leaves but not by diet-reared larvae. Our results with leaves confirm earlier studies with M. sexta using simpler substrates and mixtures of test compounds and provides further evidence that leaf phenolics, such as chlorogenic acid, do not act as feeding deterrents for larval M. sexta.

Original languageEnglish (US)
Pages (from-to)73-78
Number of pages6
JournalEntomologia Experimentalis et Applicata
Volume87
Issue number1
StatePublished - Jan 1 1998

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics
  • Insect Science

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