Baseline susceptibility of tobacco budworm (Lepidoptera: Noctuidae) to Cry1F toxin from Bacillus thuringiensis.
Transgenic cotton, Gossypium hirsutum L., lines expressing both Cry1F and Cry1Ac insecticidal proteins from Bacillus thuringiensis (Bt) have been commercially available in the United States since 2005. Both Bt proteins are highly effective against tobacco budworm, Heliothis virescens (F.), and other lepidopteran pests of cotton. Although CrylAc has been available in Bt cotton since 1996, the Cry1F component is relatively new. As part of the proactive resistance management program for Cry1F/Cry1Ac cotton, a susceptibility-monitoring program is being implemented. Baseline variation in the susceptibility to Cry1F in field populations of tobacco budworm was measured. There was a three-fold variation in the amount of Cry1F needed to kill 50% of the neonates from 15 different field populations from the southern and central United States. Future variation in susceptibility of tobacco budworm populations to Cry1F or even resistance evolution could be documented based on this baseline data. A candidate diagnostic concentration was determined that may be efficiently used to identify individuals that potentially carry major alleles conferring field-relevant resistance to Cry1F before such alleles spread through field populations.
Blanco
Carlos A
CA
USDA-ARS, Southern Insect Management Research Unit, Stoneville, MS 38776, USA. cblanco@ars.usda.gov
Storer
Nicholas P
NP
Abel
Craig A
CA
Jackson
Ryan
R
Leonard
Rogers
R
Lopez
Juan D
JD
Payne
Gregory
G
Siegfried
Blair D
BD
Spencer
Terence
T
Terán-Vargas
Antonio P
AP
D000818:Animals; D001413:Bacillus thuringiensis / Q000378:metabolism; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000494:pharmacology*; D004731:Endotoxins / Q000096:biosynthesis / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant; D003368:Gossypium / Q000235:genetics / Q000469:parasitology; D006460:Hemolysin Proteins; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology; D007915:Lepidoptera / Q000187:drug effects* / Q000254:growth & development; D010572:Pest Control, Biological; D030821:Plants, Genetically Modified; D014026:Nicotiana / Q000235:genetics / Q000469:parasitology*
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis