Isolation and characterization of lectin gene from vigna aconitifolia (L.), (Jacq.) marechal, and genetic transformation of brassica juncea (L.) czern & coss, for the development of resistance against sap sucking insect pest

Abstract

India is one of the largest rapeseed-mustard growing countries in the world, occupying the first position in area and second position in production after China. After groundnut Brassica (rapeseed-mustard) is the second most important edible oilseed crop in India and cultivated in around 6 million hectares accounting nearly 30% of the total oilseeds produced in the country. When compared to other edible oils, the rapeseed/ mustard oil has the lowest amount of harmful saturated fatty acids. It also contains adequate amounts of the two essential fatty acids, linoleic and linolenic acid, which are not present in many of the other edible oils. The projected demand for oilseeds in India is around 34 million tonnes by 2020, of which about 14 million tonnes (41%) is to be met by mustard alone. Brassica juncea (L.) Czern and Coss a major oilseed crop of Indian sub-continent is considerably hindered by various insect-pests and diseases. The yield losses could be as high as 90% due to aphids (Lipaphis erysimi) alone. Conventional breeding techniques are of limited use as cultivated Brassica normally do not have any inherent resistance against the aphids. The advances in plant genetic engineering in recent years have opened new avenues for crop improvement by introducing resistance genes from other crops into desired crops. Plant lectins, the highly specific carbohydrate binding proteins, are reported to have insecticidal properties. Lectins are currently receiving most interest as insecticidal agents against these sap-sucking insects. When seeds or other plant organs are eaten by predators, lectins come in contact with the intestinal tracts of the predators, possibly inhibiting absorption of nutrients resulting stunted growth of pests and eventually the insect dies. Thus, it is important to isolate lectin gene and transfer them to agronomically important crop plants for developing resistance against aphids for enhancing crop yield.