Development of Transgenic Cotton Lines Expressing Allium sativum Agglutinin (ASAL) for Enhanced Resistance against Major Sap-Sucking Pests

Abstract

Mannose-specific Allium sativum leaf agglutinin encoding gene (ASAL) and herbicide tolerance gene (BAR) were introduced into an elite cotton inbred line (NC-601) employing Agrobacterium-mediated genetic transformation. Cotton transformants were produced from the phosphinothricin (PPT)-resistant shoots obtained after co-cultivation of mature embryos with the Agrobacterium strain EHA105 harbouring recombinant binary vector pCAMBIA3300-ASAL-BAR. PCR and Southern blot analysis confirmed the presence and stable integration of ASAL and BAR genes in various transformants of cotton. Basta leaf-dip assay, northern blot, western blot and ELISA analyses disclosed variable expression of BAR and ASAL transgenes in different transformants. Transgenes, ASAL and BAR, were stably inherited and showed co-segregation in T1 generation in a Mendelian fashion for both PPT tolerance and insect resistance. In planta insect bioassays on T2 and T3 homozygous ASAL-transgenic lines revealed potent entomotoxic effects of ASAL on jassid and whitefly insects, as evidenced by significant decreases in the survival, development and fecundity of the insects when compared to the untransformed controls. Furthermore, the transgenic cotton lines conferred higher levels of resistance (1–2 score) with minimal plant damage against these major sucking pests when bioassays were carried out employing standard screening techniques. The developed transgenics could serve as a potential genetic resource in recombination breeding aimed at improving the pest resistance of cotton. This study represents the first report of its kind dealing with the development of transgenic cotton resistant to two major sap-sucking insects.

Development of a Triple Gene Cry1Ac-Cry2Ab-EPSPS Construct and Its Expression in Nicotiana benthamiana for Insect Resistance and Herbicide Tolerance in Plants

“…Problems associated with hazardous pesticides, herbicide and lack of desired traits in cotton germplasm can be addressed by application of biotechnology. Various insect resistance genes have been introduced into cotton using genetic engineering to provide better protection against insect pests (Vajhala et al, 2013). Different studies have shown the development of single gene or double gene constructs for bt genes developed under 35S promoter for cotton transformation.…”

Transgenic Cotton Plants Expressing Cry1Ia12 Toxin Confer Resistance to Fall Armyworm (Spodoptera frugiperda) and Cotton Boll Weevil (Anthonomus grandis)

“…Different methods of transferring exogenous genes into cotton plants have been studied and used in recent decades. The most common techniques used for cotton transformation are Agrobacterium -mediated ( Wu et al, 2008 ; Kumar et al, 2009 ; Mao et al, 2011 ; Vajhala et al, 2013 ) and particle bombardment ( McCabe and Martinell, 1993 ; Rajasekaran et al, 1996 ; Rech et al, 2008 ; Rajasekaran, 2013 ). Other methods, including the direct delivery of DNA into protoplasts by electroporation and PEG-mediated gene transfer, have also been successfully employed ( Chilton, 2005 ; Vain, 2007 ).…”

Tiny Flies: A Mighty Pest That Threatens Agricultural Productivity—A Case for Next-Generation Control Strategies of Whiteflies

“…Likewise, lectins of plant origin such as Allium sativum leaf agglutinin (ASAL; LC 50 = 8.5 μg/mL) from Allium (garlic) leaves, Pinellia ternata agglutinin (PTA) from Pinellia ternate (Chinese medicinal herb), Remusatia vivipara lectin (RVL1) from Remusatia vivipara , and Colocasia esculenta agglutinin (CEA; LC 50 = 5.17 μg/mL in insect bioassay using artificial diet) from Colocasia esculenta (taro) have been reported to confer toxicity against the sweetpotato whitefly [ 158 , 159 , 160 , 161 ]. Transgenic plants expressing ASAL, and PTA have been found to exhibit various entomotoxic effects with low mortality such as decreased nymphal emergence, development, fecundity, and population build-up of B. tabaci [ 158 , 159 ]. Application of lectins in genetic engineering approaches might be limited due to their higher doses required to obtain significant control over the pest and prevention of viral transmission.…”