REDUCTION OF RISK FOR GROWERS - METHODS FOR THE DEVELOPMENT OF DISEASE-RESISTANT CROPS

Systemic acquired resistance (SAR) appears to be a ubiquitous higher p lant defence response. Resistance is dependent on the high-level expre ssion of SAR genes. Mutations, transgenes or chemicals that cause high -level SAR gene expression also cause resistance to pathogens. Further more, when SAR is eliminated, through the reduction of salicylic acid accumulation or activity, generalized severe disease-susceptibility oc curs. Therefore, SAR appears to be an essential component of the defen sive repertoire that ensures plant health in nature. Chemicals that ac tivate SAR in the field, as well as crop varieties with constitutive S AR gene expression, will provide new solutions to disease problems for growers in the near future.