Development of insect-resistant cotton lines with targeted expression of insecticidal gene

Abstract

In order to address biosafety concerns regarding the constitutive expression of foreign genes in crops, we applied a strategy aimed at confining foreign gene expression in insect wounding sites of cotton. For this purpose, a plant expression construct was designed by cloning the AoPR1 promoter (pathogenesis-related protein gene isolated from Asparagus officinalis) upstream from the insecticidal gene cry1Ac. The Turkish cotton cultivar cv. STN-468 was transformed using the Agrobacterium tumefaciens strain LBA4404 containing the recombinant binary vector pRD400 harboring cry1Ac under a wound-inducible promoter. The neomycin phosphotransferase (nptII) gene was used as a selectable marker at a concentration of 100 mg/L. The primary transformants were analyzed for T-DNA integration and expression using standard molecular approaches. The efficacy of insecticidal gene control of the AoPR1 promoter was investigated using leaf bioassays with 2 nd instar larvae of Helicoverpa armigera and Spodoptera littoralis. Positive primary transformants from T 0 progeny were further raised under greenhouse conditions to obtain progeny (T 1 ). The introduced gene was properly inherited and expressed in T 1 progeny. The mechanical wounding of plants resulted in increased cry1Ac protein levels during 0-48 h of the wounding period. The transgenic lines exhibited appreciable levels of resistance against targeted insect pests in the leaf bioassays. The use of a wound-inducible promoter to drive insecticidal gene expression is a valuable insect resistant management strategy as gene expression will remain limited to the insect biting sites of plant and crop, food and environmental concerns can be minimized.

Tissue-specific and stress-inducible promoters establish their suitability for containment of foreign gene(s) expression in transgenic potatoes

“…The knowledge about the choice and efficiency of a promoter is handy for researchers especially using new genome editing techniques like RNA interference and Crispr-Cas-9. The commercialized crop express insect or herbicide resistant gene(s) under the control of 35S CaMV; a widely used constitutive promoter (Ho et al 1999;Bakhsh et al 2016). There are different concerns about the use of virus based promoters in genetically modified crops (Ho et al 1999;Podevin and Du Jardin 2012;Khabbazi et al 2018) that provides impetus for the use of plant origin promoters in next generation genetically modified (GM) or non GM crops.…”

Development and Evaluation of the Cotton Leaf Curl Kokhran Virus-Burewala Bidirectional Promoter for Enhanced Cry1Ac Endotoxin Expression in Bt Transgenic Cotton

“…The DNA-A genome of monopartite begomoviruses possesses a LIR sequence that functions as a bidirectional promoter, essential for replication and expression of the viral genes, C1 (replication associated protein) and V1 (coat protein) [19,20]. Recently, Cry1Ac endotoxin expression in plants has been driven by plant promoters including the rbcS [10,21], AoPR1 [22,23], ats1A [24,25], and maize ubiquitin-1 promoters [26].…”

An effective pest management approach in potato to combat insect pests and herbicide

“…These transgenic plants are becoming important components of integrated pest management worldwide (Kos et al 2009). According to the literature, use of 35S CaMV promoter has been the first choice of all researchers to express foreign protein genes constitutively in commercialized transgenic crops; however, the targeted expression of foreign gene proteins has immense significance in transgenic technology to address the concerns of unnecessary protein production, and to avoid extra metabolic burden on plants (Ahmed et al 2017;Bakhsh et al 2016). It has already been established that cry1 toxin shows efficacy against lepidopterans (Bravo et al 2007); however, there are very few reports about their efficacy against CPB (Yüceer and Kayım 2012).…”