DEVELOPMENT AND FIELD-TESTING OF WALNUTS EXPRESSING THE CRY1A(C) GENE FOR LEPIDOPTERAN INSECT RESISTANCE

Walnut trees expressing a modified cry1A(c) insecticidal protein from Bacillus thuringiensis were developed from somatic embryos and established in field trials. The cry1A(c) gene was inserted into several walnut genotypes including the commercial cultivar ‘Chandler’. Initial screening for transformants utilized kanamycin resistance and GUS marker genes. Expression and efficacy of Cry1A(c) protein were bioassayed using intact or freeze dried somatic embryos and 1st instar codling moth (Cydia pomonella) larvae. Production of the Cry1A(c) protein was confirmed and quantified by Western analysis. There was wide variation in expression between selected lines but generally levels of GUS activity, protein expression and insect mortality corresponded. Alteration of the wild-type nucleic acid sequence was important in achieving efficacy. Trees in field trials are beginning to produce nuts.

IV International Walnut Symposium

C.A. Leslie, G.H. McGranahan, A.M. Dandekar, S.L. Uratsu, P.V. Vail, J.S. Tebbets

walnut (Juglans regia L.), Agrobacterium tumefaciens, codling moth (Cydia pomonella), Bacillus thuringiensis, insect resistance

https://doi.org/10.17660/ActaHortic.2001.544.26