Expression of a Bacterial Chitinase (<i>ChiB</i>) Gene Enhances Resistance against <i>Erysiphae polygoni</i> Induced Powdery Mildew Disease in the Transgenic Black Gram (<i>Vigna mungo</i> L.) (cv. T9)

Abstract

To enhance the antifungal response of blackgram ( Vigna mungo L.), transgenic plants were generated by transferring bacterial chitinase gene with a CaMV 35S promoter. The chopped multiple shoot cells developed on the cotyledonary node were transformed by Particle gun method . Thecalli were raised on the Murashige and Skoog (MS) modified media supplemented with 50 m&middot;gl-1 kanamycin. The transformation efficiency was 13% approximately. The resultant shoot buds were selected and the antibiotic resistant transgenic plantlets were regenerated. The development of the transgenic plants from the shoot buds took about four to six months. The integration of the transgene was confirmed by PCR, RT-PCR, Southern and western blot analyses. The transgenic plants exhibited higher chitinase activity than the non-transformed ones. The chitinase activity was examined by native polyacrylamide in-gel assay. The transgenic plants showed fungal tolerance as evidenced by the delayed onset of the disease and smaller lesions following an in vitro inoculation of the powdery mildew pathogen ( Erysiphae polygoni DC). The transgenic plants adapted well to the greenhouse and did not show any phenotypic alterations.