Woronin

Woronin bodies are small, dense organelles found in the hyphae of many filamentous fungi. They are named after the Russian botanist Alexander Woronin, who first described them in the 19th century. These organelles are typically located near septa, especially close to the septal pores, where they can act rapidly in response to injury.

Biogenesis and composition: Woronin bodies are derived from peroxisomes. In several fungi, notably many Ascomycota, they contain a major protein component known as HEX-1 that forms a crystalline core. The bodies are tethered near septa and can be mobilized to the septal pore to aid sealing. The exact molecular makeup and regulatory mechanisms can vary among fungal groups.

Function and mechanism: The principal role of Woronin bodies is to seal damaged hyphal compartments. When a filament is wounded or subjected to stress, the bodies rapidly move to the septal pore and plug it, halting cytoplasmic leakage into adjacent compartments. This rapid occlusion helps preserve the integrity of the remaining mycelium and prevents loss of cellular contents, contributing to the fungus’s survival under adverse conditions.

Distribution and significance: Woronin bodies are widespread in filamentous fungi, particularly among Ascomycota, but are not universal and are often absent in yeasts. They represent a key adaptation for maintaining hyphal integrity after injury and are a focus of ongoing research into the cellular biology of fungi and potential antifungal targets.