Engineering Resistance in Brinjal against Nematode (Meloidogyne Incognita) Using cry1Ab Gene from Bacillus Thuringiensis Berliner

Abstract

Transgenic brinjal plants (Solanum melongena cv. Co2) expressing cryIAb gene from Bacillus thuringiensis Berliner (Bt) were evolved by Agrobacterium-mediated transformation system. In the present study, 7 T0 lines (PCo2IAb- 5, P-Co2IAb-9, P-Co2IAb-10, P-Co2IAb-12, PCo2IAb- 16, P-Co2IAb-17 and P-Co2IAb-22) harboring cryIAb gene were obtained. PCR and Southern blotting analyses proved the presence and integration of cryIAb in these lines. A polyclonal rabbit anti-CryIAb antiserum detected the expression of a 65 kDa CryIAb polypeptide in all these lines. Expression of CryIAb protein in those transgenic lines was also confirmed by lateral flow sticks (CryIAb) assay. Molecular analyses in T₁ progenies harboring cryIAb gene proved the presence and expression of the transgene of interest. The chi-square (χ²) tests revealed a 3:1 segregation ratio for cryIAb gene in the lines viz., P-Co2IAb-5 and PCo2IAb- 9, indicating that the transgene was integrated at a single locus.

The transgenic lines thus obtained in this study were used to investigate the potential of the CryIAb protein in controlling the root knot nematode, Meloidogyne incognita. Bioassay for root knot nematode resistance in T₁ plants expressing CryIAb showed that there was a significant decrease in number of galls and eggmasses in cryIAb-transgenic lines (P-Co2IAb-5 and PCo2IAb- 9) as compared to control. In addition, there was a significant decrease in the number of eggs per eggmass on those transgenic lines tested than the non-transgenic controls. Thus, transgenic Bt-brinjal plants could also form a part of an integrated nematode management program.