The plantibody approach: expression of antibody genes in plants to modulate plant metabolism or to obtain pathogen resistance

Immunomodulation is a molecular technique that allows the interference with cellular metabolism or pathogen infectivity by the ectopic expression of g enes encoding antibodies or antibody fragments. In recent years, several re ports have proven the value of this tool in plant research for modulation o f phytohormone activity and for blocking plant-pathogen infection. Efficien t application of the plantibody approach requires different levels of inves tigation. First of all, methods have to be available to clone efficiently t he genes coding for antibodies or antibody fragments that bind the target a ntigen. Secondly, conditions to obtain high accumulation of antigen-binding antibodies and antibody fragments in plants are being investigated and opt imized. Thirdly, different strategies are being evaluated to interfere with the function of the target molecule, thus enabling immunomodulation of met abolism or pathogen infectivity. In the near future, optimized antibody gen e isolation and expression, especially in reducing subcellular environments , such as the cytosol and nucleus, should turn immunomodulation into a powe rful and attractive tool for gene inactivation, complementary to the classi cal antisense and co-suppression approaches.