Transgenic potato plants expressing the nptII-gus marker genes affect survival and development of the Colorado potato beetle

Despite the routine use of marker genes in genetically engineered plants, little is known about the influence of the marker proteins produced by transgenic plants on phytophagous insects. Among the few available marker genes, the nptII gene encoding the neomycin phosphotransferase II and the uid A (gus) gene, encoding for the -glucuronidase activity, are commonly used. Control untransformed plants and three independent transgenic lines of potato plants from the cultivar Désirée carrying only one insert of the gene construct nptII-gus and exhibiting different -glucuronidase activity were used to breed Colorado potato beetles, Leptinotarsa decemlineata. Our results show that consumption of foliage of some of these transgenic plants leads to physiological alterations of the beetle feeding. Post-embryonic development of beetles fed with the foliage of the nptII-gus transformed line exhibiting the higher -glucuronidase activity is shortened by more than 2 days. Imagos emerged from such larvae show higher weight (more than 10%) and size (at least 0.15 mm more) and survive on average 6 days more in complete starvation. Moreover, the number of modified biological parameters and the intensity of the modifications are closely related with the -glucuronidase activity level of these transgenic lines. It is suggested that -glucuronidase expression in potato plants affects development and survival of this phytophagous beetle. © 2002 Elsevier Science Ireland Ltd. All rights reserved