Recognition of pathogens by plants

Plants must respond appropriately to a broad array of abiotic and biotic factors in the attempt to accumulate nutrient reserves and reach reproductive maturity. To complicate matters, their stockpile of nutrients makes them prime targets for pathogen attack. Phytopathogenic bacteria, fungi, and viruses all make raids on the stockpile, yet most plants are able to remain disease free. Plants have many preformed mechanisms for preventing pathogen ingress, such as waxy cuticles and constitutively produced toxic compounds. Additionally, most pathogens are highly specialized and only cause disease on a narrow host range. Nevertheless, many pathogens are capable of circumventing preformed defenses, and plants must prevent disease by recognizing these invaders and halting their growth.