Avidin expressed in transgenic tobacco leaves confers resistance to two noctuid pests, Helicoverpa armigera and Spodoptera litura.
Fertile transgenic tobacco plants with leaves expressing avidin in the vacuole have been produced and shown to halt growth and cause mortality in larvae of two noctuid lepidopterans, Helicoverpa armigera and Spodoptera litura. Late first instar H. armigera larvae and neonate (< 12-h-old) S. litura larvae placed on leaves excised from T0 tobacco expressing avidin at 3.1-4.6 microM (micromoles/kg of fresh leaf tissue) had very poor growth over their first 8 days on the leaves, significant numbers had died by days 11 or 12 and all were dead by day 22 (H. armigera) or day 25 (S. litura). Similar results were obtained when late first instar H. armigera larvae were placed on leaves from T1 plants expressing avidin at six different average concentrations, ranging from 3.7 to 17.3 microM. Two larvae on the lowest expressing leaves survived to pupation, but there was total mortality among the other groups and no relationship between avidin concentration and the effects on the larvae. Synergistic effects between avidin-expressing tobacco plants and a purified Bt toxin, Cry1Ba, were demonstrated. Late instar H. armigera larvae fed with leaves from T2 plants expressing avidin at average concentrations of either <5.3 or > 12.9 microM, and painted with Cry1Ba protein at a rate equivalent to an expression level of 0.5% of total leaf protein, died significantly faster than larvae given either of the two treatments alone. Larvae fed with avidin-expressing leaves painted with the protease inhibitor, aprotinin, at a rate equivalent to 1% of total leaf protein had mortality similar to those given avidin-leaves alone. There was no evidence of antagonism between these two proteins.
Burgess
Elisabeth P J
EP
The Horticulture and Food Research Institute of New Zealand Limited, Mt Albert Research Center, Auckland. eburgess@hort.cri.nz
Malone
Louise A
LA
Christeller
John T
JT
Lester
Melissa T
MT
Murray
Colleen
C
Philip
Bruce A
BA
Phung
Margaret M
MM
Tregidga
Emma L
EL
D016960:Agrobacterium tumefaciens / Q000235:genetics; D000818:Animals; D007611:Aprotinin / Q000494:pharmacology; D001360:Avidin / Q000235:genetics* / Q000494:pharmacology; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000494:pharmacology; D001427:Bacterial Toxins; D004731:Endotoxins / Q000494:pharmacology; D005822:Genetic Vectors; D006460:Hemolysin Proteins; D007306:Insecticides; D007814:Larva / Q000187:drug effects; D009036:Moths; D010572:Pest Control, Biological; D030821:Plants, Genetically Modified; D018411:Spodoptera; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics* / Q000469:parasitology; D014617:Vacuoles / Q000378:metabolism
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D001360:Avidin; D007611:Aprotinin