Skip to main content
ARS Home » Research » Publications at this Location » Publication #166528
Title: TOWARDS IMPROVED INSECT RESISTANCE IN PAPAYA

Author
item MCCAFFERTY, HEATHER - HI AG RES CNT
item Moore, Paul
item ZHU, Y - HI AG RES CNT

Submitted to: Compiled Abstracts for Annual Meeting of American Society of Plant Biologists in Hawaii July 2003
Publication Type: Abstract Only
Publication Acceptance Date: 2/20/2003
Publication Date: 7/25/2003
Citation: McCafferty, H.R., Moore, P.H., Zhu, Y.J. 2003. Towards improved insect resistance in papaya. Compiled Abstracts for Annual Meeting of American Society of Plant Biologists in Hawaii July 2003. Plant Biology 2003: P731, pg 158.

Interpretive Summary:

Technical Abstract: Insect resistance has been achieved in several plant species through transgenic expression of Bacillus thuringiensis (Bt) protein genes. In addition to the Bt approach, transgenic insect-resistant plants have been developed through the introduction and expression of genes encoding plant defense proteins such as protease inhibitors or lectins, which have anti-metabolic action against insects. We are evaluating the transgene expression of Manduca chitinase for increasing papaya resistance to its major insect pests, Stevens leafhopper (Empoasca species) and carmine spider mites (Tetranychus cinnabarinus). The Manduca chitinase gene, originally isolated from Manduca sexta larvae, was placed into the pBI121 binary vector containing the .-glucuronidase gene as a reporter and the NPTII gene as a selectable marker, all under the control of a 35S promoter. The biolistic gene gun was used to introduce the transgene vector into the papaya cultivar Kapoho. Bombarded embryogenic calli were selected on tissue growth media containing G418. Integration of the transgenes in surviving plants was confirmed by molecular analysis. A laboratory test evaluated insect resistance of lines shown to contain the Manduca chitinase gene. Plants were naturally infected with carmine spider mite adults then grown in the laboratory under artificial light for evaluation. The initial mite population was recorded and adult mites were counted at weekly intervals. Additional data included how the mites were distributed and the number of leaves dropped from the plants. Data show that the Manduca chitinase transgene improved papaya tolerance against carmine spider mites. Preliminary field evaluation of transgenic plants against leafhoppers and carmine spider mites are under way and will be presented.