High necrosis and poor survival rate of target plant tissues are some of the major factors that affect the efficiency of Agrobacterium-mediated T-DNA transfer into plant cells. These factors may be the result of, or linked to, hypersensitive defense reaction in plants to Agrobacterium infection, which may involve the recognition of specific signals from the Agrobacterium that triggers the burst of reactive oxygen species at the infection site. Evidences of Agrobacterium-induced necrosis in target plant tissues and its link to reactive oxygen species are presented. Application of antioxidants, addition of acetosyringone and optimization of pre-culture conditions suppress the Agrobacterium-induced hypersensitive necrotic response in target plant tissues, thereby enhancing stable transformation.

Key words: Agrobacterium; hypersensitive reaction; necrosis; signal transduction; oxidative burst; transformation.