TRANSFORMATION OF EGGPLANT WITH SYNTHETIC CRYIIIA GENE PRODUCES A HIGH-LEVEL OF RESISTANCE TO THE COLORADO-POTATO BEETLE

A population of 300 putative transgenic eggplants (Solanum melongena L .) carrying the syn cryIIIA gene was produced and tested for resistanc e to the Colorado potato beetle [CPB; Leptinotarsa decemlineata (Say)] , Toxicity tests in planta and in vitro demonstrated that 69% of the t ransformed plants were resistant to neonate larvae and adult CPB. Tran sgenicity of the plants was confirmed by studies of GUS expression and Southern and northern analysis, Primary transformants, having a singl e insert of the construct, upon selfing, produced progenies cosegregat ing for the uidA and syn cryIIIA genes at the expected 3:1 ratios with a few exceptions in which only one of the genes was expressed, The la tter was attributed to the gene silencing phenomenon. The segregating resistant RI seedlings showed the same level of resistance as the pare ntal genotypes in growth chamber tests and under field conditions. One genotype carrying two copies of the construct, upon selfing, segregat ed at a 15:1 ratio for GUS expression and resistance to CPB, while Sou thern analysis revealed a 9:3:3:1 genotypic segregation ratio for indi vidual copies of the construct.