Expression of an endochitinase gene from Trichoderma virens confers enhanced tolerance to Alternaria blight in transgenic Brassica juncea (L.) czern and coss lines

An endochitinase gene 'ech42' from the biocontrol fungus 'Trichoderma virens' was introduced to Brassica juncea (L). Czern and Coss via Agrobaterium tumefaciens mediated genetic transformation method. Integration and expression of the 'ech42' gene in transgenic lines were confirmed by PCR, RT-PCR and Southern hybridization. Transgenic lines (T-1) showed expected 3:1 Mendelian segregation ratio when segregation analysis for inheritance of transgene 'hpt' was carried out. Fluorimetric analysis of transgenic lines (T-0 and T-1) showed 7 fold higher endochitinase activity than the non-transformed plant. Fluorimetric zymogram showed presence of endochitinase (42 kDa) in crude protein extract of transgenic lines. In detached leaf bioassay with fungi Alternaria brassicae and Alternaria brassicicola, transgenic lines (T-0 and T-1) showed delayed onset of lesions as well as 30-73 % reduction in infected leaf area compared to non-transformed plant.