Development of Transgenic Rice Harbouring Mutated Rice 5-Enolpyruvylshikimate 3-Phosphate Synthase (Os-mEPSPS) and Allium sativum Leaf Agglutinin (ASAL) Genes Conferring Tolerance to Herbicides and Sap-Sucking Insects

Abstract

Globally, weeds and sap-sucking insects are major constrains in rice production. We have combined two desired traits for resistance to glyphosate and sapsuckers by transgenic overexpression of mutated rice 5-enolpyruvylshikimate3-phosphate synthase (Os-mEPSPS) and garlic leaf lectin (Allium sativum leaf agglutinin, ASAL) in a high yielding IR-64 rice cultivar. Polymerase chain reaction (PCR), southern and genome walking analyses showed stable integration of transgenes in genomes of transgenic lines. The molecular analysis of transgenic lines revealed effective expression of both Os-mEPSPS and ASAL transcripts and their respective proteins and imparted resistance to glyphosate and brown planthopper. In planta brown hopper assays in the progenies of independent rice transgenic lines exhibit enhanced ASAL expression that imparts substantial level of resistance, reduced survival and fecundity of brown hoppers by ~74 and ~68 %, respectively. The glyphosate and sap-sucking insect pest-resistant transgenic rice lines showed normal phenotype and no growth penalty or fitness costs. The double transgenic traits co-segregated as a single unit in the subsequent generations. In spite of the presence of several herbicide- and insect-resistant GM rice crops in the market, there is a need to develop new transgenic rice lines by selecting the transgenes from homologous and/or edible crop sources that circumvent the biosafety issues raised by regulatory bodies regarding the acceptance of these products for human consumption. In this scenario, the transgenic rice varieties generated in this study serve as a novel genetic resource in rice breeding aimed at durable resistance to glyphosate and sap-sucking insect pests.