Characterization and Expression of Plant Defense Genes in Peach and Tomato

Abstract

The influence of three different agar concentrations, 0.8, 1.0, and 1.2%, on tomato transformation efficiency was examined. Cotyledons of Lycopersicon esculentum cv. 'Sweet Chelsea' were cocultivated with Agrobacterium tumefaciens strain GV3101 harboring derivatives if the binary vector pCAMBIA 2301. The binary vectors pGR-1, pChi-1, pRIP-1, and pAFP-1 carried a maize beta-glucanase, maize chitinase, iris ribosome-inactivating protein (RIP), or an antimicrobial protein gene, respectively, each driven by the CaMV 35S promoter. Transformation was initially verified by the presence of an nptII gene and GUS enzyme activity in the uidA reporter gene, both engineered into the gene construct. Further confirmation of the transgenics was accomplished by Southern blot hybridization. Lines containing the transgenes were exposed to the tomato fungal pathogen Alternaria solani. The plants were assessed for pathogen susceptibility. Selected beta-glucanase and Mj-AMP lines were more resistant to early blight than non-transformed lines.