What is the difference between a appressorium vs haustorium?

Answer 1

An appressorium is a specialized structure formed by certain fungi, particularly plant pathogens, that enables them to penetrate the host plant's surface by generating pressure. In contrast, a haustorium is a specialized feeding structure that grows into host plant tissues, allowing the fungus to extract nutrients. While appressoria facilitate entry into the host, haustoria are primarily involved in nutrient absorption once the pathogen has established itself within the plant. Both structures are critical for the pathogenic lifecycle of fungi.