ISHS Acta Horticulturae 336: II International Symposium on In Vitro Culture and Horticultural Breeding
TRANSGENIC APPLES AND STRAWBERRIES: ADVANCES IN TRANSFORMATION, INTRODUCTION OF GENES FOR INSECT RESISTANCE AND FIELD STUDIES OF TISSUE CULTURED PLANTS |
| Authors: | D.J. James, A.J. Passey, A.D. Webster, D.J. Barbara, P. Viss, A.M. Dandekar, S.L. Uratsu |
| Keywords: | Agrobacterium virulence |
| Abstract:
A number of factors affecting the transcription of the vir genes of Agrobacterium tumefaciens in the leaf disc transformation procedure and believed to limit the efficiency of regeneration of transgenic apples have been investigated. The presence in the virulence induction medium of the plant signal molecule acetosyringone, and of the osmoprotectant betaine phosphate, has been shown to increase the efficiency of transformation as monitored by fluorometric determinations of GUS activity in apple leaf discs infected with a disarmed strain of Agrobacterium tumefaciens harbouring the vector pKIWI105. Transgenic apple and strawberry plants have now been regenerated that carry genes for insect resistance. A gene encoding a cowpea trypsin inhibitor (CpTI) has been inserted into both apple and strawberry and the gene CrylA(c) from Bacillus thuringiensis encoding an intracrystalline protein has been inserted into apple. In 1992 in the USA, permission to field trial apple plants carrying CrylA(c) has recently been obtained from APHIS. Field trials in the UK of several hundred individual untransformed clones of apple trees regenerated in vitro from leaf discs of the cv. Greensleeves have shown that the fruit from such trees show no obvious sign of somaclonal variation after two cropping years. | |
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