CONVERGENT INSIGHTS INTO MECHANISMS DETERMINING DISEASE AND RESISTANCE RESPONSE IN PLANT-FUNGAL INTERACTIONS

In this review, an attempt has been made to scrutinize mechanisms controlling disease or resistance from the perspective of biological forces and constraints affecting co-evolution of a fungal pathogen with its plant host. We reckon that plants are naturally resistant to almost all potentially pathogenic organisms. Defense mechanisms responsible for this default resistance, also termed nonhost or general resistance, are many and include both physical and chemical factors triggered rapidly in response to attempted infection. Pathogenic organisms have to contend with these mechanisms before they can succeed in colonizing a plant. It appears that two different strategies, biotrophic and necrotrophic, have evolved in fungi for this purpose. In the former, defenses are not allowed to be triggered, and in the latter these mechanisms are suppressed or nullified. Consequently, two different kinds of resistance mechanisms have evolved in plants. Against biotrophs, resistance genes function to ensure that normal pl...