Expression of cry1Ac9 and cry9Aa2 genes under a potato light-inducible Lhca3 promoter in transgenic potatoes for tuber moth resistance

Abstract

In transgenic potato it is often desirable to couple high-level expression in foliage with no expression in the edible tubers, especially for resistance to pests that primarily infest foliage. To accomplish this we have investigated the use of a light inducible Lhca3 promoter for transcriptional control of cry1Ac9 and cry9Aa2 genes for resistance to potato tuber moth (PTM) (Phthorimaea operculella). Thirty-five and thirty-one independently derived transgenic lines of potato cultivar Iwa were regenerated for the cry1Ac9 and cry9Aa2 genes respectively. Significantly inhibited larval growth of PTM on excised greenhouse-grown leaves was observed in 51% of the cry1Ac9-trangenic lines and 84% of the cry9Aa2-transgenic lines. RT-PCR analysis identified several transgenic lines with high levels of cry gene mRNA in leaves and no to low levels in tubers. Southern and ELISA analyses on eight selected cry1Ac9-transgenic lines revealed that they contained 2 to 9 copies of the cry1Ac9 gene and the amount of Cry protein in leaves was less than 60 ng g −1 of fresh leaf tissue. Southern analysis for four selected cry9Aa2-transgenic lines revealed that they contained 2 to 6 copies of the cry9Aa2 gene. This study has established that the expression of either the cry1Ac9 gene or the cry9Aa2 gene in transgenic potato plants offers protection against PTM larval damage in foliage when expressed under the transcriptional control of a Lhca3 light-inducible promoter. Several transgenic lines were identified with high cry gene expression, high resistance to PTM larvae in the foliage, and no or minimal cry gene expression in tubers.

Germin-like protein 2 gene promoter from rice is responsive to fungal pathogens in transgenic potato plants

“…Progress in the areas of tissue culture, genetic engineering, and genomics has promoted the establishment of resistant Btransgenic^plants. One of these is the use of tissue-specific (for example tuber) promoters to control transgene expression and prevent consumer unease about probable negative influence of the foreign proteins (Kumar et al 2010;Meiyalaghan et al 2006).…”

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.…”

Transgenic Potato Lines Expressing cry1Ba1 or cry1Ca5 Genes are Resistant to Potato Tuber Moth

“…Iwa were used for co-cultivation and selection of transformed plants as previously described (Meiyalaghan et al 2006). …”

“…Experimental procedures for PCR and Southern analysis were performed exactly as previously described (Meiyalaghan et al 2006), except for the PCR primers (see Table 1) and the radioactively-labeled DNA probe for Southern analysis was a 1.35 kb fragment corresponding to the CaMV 35S promoter sequence.…”

“…To date, several cry genes have been demonstrated to be highly effective at controlling PTM when expressed in potato plants. These include: cry1Ab (Jansens et al 1995;Rico et al 1998;Cañedo et al 1999;Chakrabarti et al 2000), cry1Ac (Ebora et al 1994), cry1Ac9 (Davidson et al 2002(Davidson et al , 2004Meiyalaghan et al 2006), cry1Ia1 (Douches et al , 2002Westedt et al 1998;Li et al 1999;Lagnaoui et al 2000;Mohammed et al 2000), and cry9Aa2 (Meiyalaghan et al 2006). To further increase the diversity of cry genes for control of PTM in potato, this study evaluated the effectiveness of modified cry1Ba1 and cry1Ca5 genes to confer resistance to PTM when expressed in transgenic potato.…”