teliospores

Teliospores are thick-walled resting spores produced by certain basidiomycete fungi, most notably rust fungi (Pucciniales) and smut fungi (Ustilaginales). They represent a late, often overwintering stage in the fungal life cycle and are typically formed on specialized structures called telia within plant tissue. Teliospores are usually darkly pigmented and structurally robust, features that aid survival in harsh environmental conditions.

Formation and structure: Teliospores develop after plasmogamy and are typically diploid following karyogamy within the spore. They may be multi-celled and possess a prominent, thick wall that helps resist desiccation and temperature fluctuations. In many rusts, the teliospore germinates to produce a basidium, within which meiosis occurs to generate haploid basidiospores that serve as the infectious propagules for the next stage of the life cycle.

Role in the life cycle: The telial stage enables genetic recombination through sexual reproduction and provides a durable resting form that survives unfavorable seasons. In heteroecious rusts, basidiospores derived from teliospores infect alternate hosts and continue the complex life cycle; in smut fungi, teliospores function as the primary resting stage within the crop tissue and can contribute to disease persistence.

Importance: Teliospores are often diagnostic features used to identify rusts and smuts, due to their distinctive morphology and life-cycle significance. They vary in size, shape, and wall ornamentation among species. Agriculturally, teliospores can underpin the persistence and spread of plant pathogens such as Puccinia and Ustilago species.