Abstract

Selenium is an essential micronutrient for many organisms and plays an important role in antioxidant defense, immune regulation, and hormone metabolism. Exogenous selenium can increase the selenium content of crops and enhance the resistance of plants to diseases. Selenium can directly inhibit some pathogenic microorganisms and indirectly enhance disease resistance by activating the plant immune system. Selenium shows a dual mechanism in the prevention and control of plant diseases. On the one hand, selenium can significantly inhibit the spore germination and mycelial growth of various plant pathogens in vitro, and its inhibitory effect is concentration-dependent and reversible. On the other hand, selenium enhances host disease resistance by regulating plant morphological structure, physiological function and biochemical reaction, including optimizing cell membrane stability, improving photosynthetic efficiency, activating antioxidant enzyme system and inducing defense-related substance synthesis. Exogenous selenium can significantly reduce the incidence of tomato bacterial spot disease, citrus Huanglongbing (HLB) disease and other diseases, and provide a new strategy for the prevention and control of green agricultural diseases.