A range of structures and mechanisms to prevent pathogen entry. However, if these barriers are breached, the next line of defence involves more targeted responses
The effects of pathogens on plants include deterioration, abnormal or stunted growth, destruction of tissues, e.g. vascular tissue (xylem and phloem), discolouration of tissue, wilting, and death of the plant
If a plant can prevent a pathogen from invading its tissue or prevent it from reproducing, then it’ll be resistant to that pathogen