aecium

Aecium is a fungal structure that plays a role in the life cycle of rust fungi, which are plant pathogens. Specifically, aecium refers to the fruiting body produced by rust fungi in their dikaryotic (n+n) stage. These structures are typically found on the alternate host plant, which is often a different species from the one infected by the primary host. The aecium develops within plant tissues, appearing as small, cup-shaped or saucer-shaped structures that erupt through the surface of leaves, stems, or fruits. They are characterized by a layer of sterile cells that surround a mass of spores called aeciospores. These aeciospores are dikaryotic and are the infectious stage that can spread to the primary host, initiating a new infection cycle. The formation of aecium is a key event in the complex life cycle of many rust fungi, which often involve multiple spore stages and host plants. The appearance and location of aecia can be important diagnostic features for identifying specific rust diseases.