Recent Developments In Molecular Plant-Microbe Interactions

Generally, plants are affected by biotic and abiotic elicitors in nature. These elicitors are recognized by receptors on the plasma membrane and the information is passed to the responsible part of the cell via a signal transduction pathway. In terms of plant-pathogen interaction, the products of avr genes of the pathogens are recognized by the products of R genes of the host plant. Following recognition, the other genes, including kinases, in the cascade are phosphorylated and the defence mechanisms of the plant are activated. As a result, the plant cell commits suicide and the growth of the pathogen is restricted. Until now, several avr and R genes have been cloned or at advanced stages of being cloned. The data obtained from the molecular cloning of these genes indicate that avr gene products could be produced artifically, and when sprayed onto the plants, would activate the defence mechanisms in the absence of pathogens. This would mean, in the long term, alternative compounds to the classical pesticides could be found. As control agents, they may even find a place within the biotechnical control of plant diseases.