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Remarkable susceptibility of the diamondback moth ( Plutella xylostella ) to ingestion of Pir toxins from Photorhabdus luminescens
Author(s) -
Blackburn Michael B.,
Farrar Robert R.,
Novak Nicole G.,
Lawrence Susan D.
Publication year - 2006
Publication title -
entomologia experimentalis et applicata
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.765
H-Index - 83
eISSN - 1570-7458
pISSN - 0013-8703
DOI - 10.1111/j.1570-8703.2006.00457.x
Subject(s) - biology , plutella , manduca sexta , diamondback moth , lepidoptera genitalia , photorhabdus luminescens , plutellidae , lymantria dispar , bacillus thuringiensis , microbiology and biotechnology , manduca , heliothis virescens , pieris rapae , leptinotarsa , noctuidae , botany , pest analysis , insect , bacteria , genetics
Genes encoding Pir toxins were cloned and sequenced from Photorhabdus luminescens (Enterobacteriaceae) strain Hm. Cultures of Escherichia coli expressing the Pir A and B proteins were highly toxic when fed to larvae of Plutella xylostella L. (Lepidoptera: Plutellidae), as had been reported previously. Histological examination of P. xylostella larvae fed with recombinant E. coli revealed gross abnormalities of the midgut epithelium, with profound swelling and shedding of the apical membranes. However, the recombinant E. coli had no effect on the growth or mortality of larval Heliothis virescens F. (Lepidoptera: Noctuidae), Manduca sexta L. (Lepidoptera: Sphingidae), Lymantria dispar L. (Lepidoptera: Lymantriidae), or Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae). Based on these results, P. xylostella is at least 300‐fold more susceptible to Pir toxins than other insect species tested, suggesting that they may not be broadly useful as insecticidal proteins. Because Pir B has sequence similarities with N‐terminal portions of Cry proteins from Bacillus thuringiensis , we also tested the recombinant E. coli against a strain of P. xylostella that is resistant to the Cry 1A toxin, but found no difference in mortality between resistant and susceptible strains.