Transgenic Chickpea Plants Resistant to Sap-Sucking Insects

Chickpea is an important food legume currently grown on 12 million hectares in more than 40 countries. India is the world’s top producer of chickpea. According to the UN’s Food and Agriculture Organization, the country produces some 5 million tons annually. Chickpea production in India, however, is severely threatened by difficulties in managing several insect pests. These pests include the lepidopteran pod borer, pea leaf weevil and the sap-sucking cowpea aphid (Aphis craccivora).

Researchers at the Bose Institute in Kolkata have successfully developed transgenic chickpea plants resistant to cowpea aphids. The transgenic plants express a garlic lectin gene (asal) which encodes a mannose binding homodimeric protein. Lectins are sugar-binding proteins that mediate numerous biological processes, such as cell-cell and host-pathogen interactions. The insecticidal activity of some lectins involves the binding of the protein to the gut surface, leading to fatal abrasion in the insect’s gut lining.

The level of recombinant protein in transgenic lines, as measure by enzyme-linked immunosorbent assay (ELISA), varied between 0.08 percent and 0.38 percent of the total soluble proteins. In planta bioassay revealed significant decreases in the survival and fecundity of cowpea aphids. The scientists will next study the resistance of the transgenic chickpea lines to other sap-sucking insects.

The paper published by Transgenic Research is available for download at http://dx.doi.org/10.1007/s11248-009-9242-7