Strategies of plant biochemical defenses to pathogens and induction of plant defense applied to agriculture: A review

The current competitive agriculture drives the plant breeders to select genotypes with greater yield potential and responsive to environmental improvements. This targeted selection often does not prioritize the resistance of genotypes against pathogens as the main factor, but agronomic traits that influence greater yield potential. This targeting on the most yield potential of plants is sustained largely by the use of fungicides. However, the frequent use of fungicides causes the selection of pathogens with great aggression potential, endangering agricultural production and creating the necessity of strategies that enable reducing the fungicide use dependence. Genetic resistance, pyramiding resistance genes, and plant defense that involves the activation of defense mechanisms are strategies that help the plant defense against pathogens attack. The objective of this review was to address some of the principal biochemical plant defense mechanisms against pathogens and report some agronomic strategies that are currently reported in the literature to provide plant defense support facing pathogens. Among alternatives to fungicide use, induced systemic resistance in crops is a feasible alternative and current studies are contributing to this new reality.