Segregation and Efficacy of the <I>cry1Ia1</I> Gene for Control of Potato Tuberworm in Four Populations of Cultivated Potato

Abstract

The potato (Solanum tuberosum L.) cultivar 'SpuntaG2' contains a single copy of the Bacillus thuringiensis (Bt) cry1Ia1 gene and controls potato tuberworm (Phthorimaea operculella Zeller, Lepidoptera: Gelechiidae). Two potato cultivars and two breeding lines were crossed with SpuntaG2 creating four populations used to study cry1Ia1 segregation and efficacy. The cry1Ia1 gene segregated in each of the four populations with a 1:1 ratio. All progeny that were polymerase chain reaction positive for the cry1Ia1 gene had no surviving larvae and no leaf mining in detached leaf assays after 72 h. These results support previous evidence that SpuntaG2 carries a single copy of the cry1Ia1 gene and that transmission of the transgene from parent to progeny is not restricted and follows expected Mendelian segregation ratios. Based on detached leaf assays, the efficacy of the cry1Ia1 gene is retained through sexual transmission. If the SpuntaG2 cry1Ia1 insertion event is deregulated for commercial use, SpuntaG2 could be used for conventional breeding and the progeny carrying the SpuntaG2 event would also be available for commercial use.

EVALUATION OF TRANSGENIC POTATO LINES RESISTANCE TO POTATO TUBER MOTH, Phthorimaea operculella (ZELLER)

“…Constitutive promoters have been deployed to drive cry gene expression in transgenic potatoes resistant to PTM (Canedo et al, 1999;Douches et al, 1998Douches et al, , 2002Douches et al, and 2013Mohammed et al, 2000). However, other inducible promoters such as light-inducible promoter, Lhca3, maize light-inducible promoter, PEPC, (Meiyalaghan et al, 2006) and Green-tissue-specific, C4-PEPC-promoter (Hagh et al, 2009) were also used to regulate cry genes for resistance to the same pest.…”