Transformation of canola with a chimeric chitinase gene under control of the SP-FF synthetic pathogen-inducible promoter

Plants are constantly challenged by the invading pathogens in their natural habitat. Expression of defensive genes from a promoter that is specifically activated in response to pathogen invasion is highly desirable for engineering disease-resistant plants. In this study, synthetic promoters were placed upstream of the chimeric chitinase defense gene to produce transformation vectors. Canola plants were transformed with three constructs, pGFC, pGMPC, pBISM2 containing synthetic promoters, SP-FF (FF elements minimal promoter), SP-MP (only minimal promoter), and the CaMV 35S constitutive promoter, respectively. Enzyme activity assay indicated that the synthetic pathogen-inducible promoter (SP-FF) was responsive to the Methyl jasmonate (MJ) elicitor, whereas pGMPC, as a negative control did not respond. Transgenic lines were also evaluated for antifungal activity against two phytopathogenic fungi. Data show that leaf extracts from transgenic plants containing the SP-FF promoter treated with MJ, strongly inhibited fungal growth, especially that of Sclerotinia sclerotiorum, the major pathogen of canola. Results indicated that not only the SP-FF synthetic promoter is highly responsive to MJ, as an important chemical signal in necrotrophic pathogen defense, but the induced expression of the transgene under control of the synthetic promoter can increase the resistance of transgenic plants against pathogenic fungi.