Teleutospores

Teleutospores are a type of spore produced by rust fungi (Basidiomycota, Puccinomycotina). They represent the overwintering or oversummering stage of these fungi. Teleutospores are typically thick-walled and are formed from the fusion of two haploid nuclei within a specialized hyphal structure called a telium. This fusion leads to the formation of a diploid nucleus, which then undergoes meiosis to produce haploid basidiospores. However, the teleutospore itself is usually considered a resting spore, awaiting favorable conditions for germination.

Morphologically, teleutospores can vary greatly in shape, size, and color depending on the species. They can be single-celled (unicellular) or multicellular, and they may be borne singly or in clusters. The thick walls provide protection against adverse environmental conditions such as drought, extreme temperatures, and UV radiation.

When conditions become favorable, typically in the spring, the teleutospore germinates. This germination involves the meiosis of the diploid nucleus, followed by the production of haploid basidiospores. These basidiospores are then released and dispersed by wind or water. If they land on a suitable host plant, they can infect it, initiating a new life cycle of the rust fungus. Teleutospores are crucial for the survival and long-term persistence of many rust diseases in agricultural and natural ecosystems.