Life Cycle and Lectin-Binding Patterns in the Chytrid Fungus <i>Chytriomyces hyalinus</i>

Abstract

Summary Chytrids are an early diverging group of fungi possessing a flagellated spore stage in their life cycle. Chytrid infections in amphibian species and algae are currently a major problem worldwide. Lectin binding patterns are key factors involved in host-parasite interactions. However, there are no analyses of the lectin binding pattern for core chytrids (e.g., species belonging to Chytridiales). Here we present time-lapse observations of the early development of the vegetative stage and lectin binding patterns to examine sugar composition during the asexual life cycle of the core chytrid Chytriomyces hyalinus ATCC 28165. The lectin binding assay showed that the signal of wheat germ agglutinin was detected in the chytrid cell wall and basal part of the rhizoidal system, but not in the zoospore and rhizoid system. This result indicated that N-acetyl-D-glucosamine was accumulated highly at the basal part of the rhizoid system in C. hyalinus.

A Call for a Better Understanding of Aquatic Chytrid Biology

“…The apophysis is the subsporangial swelling in many chytrids that links the sporangia to the substrate attaching and feeding rhizoids (Laundon et al, 2020 ). Fluorescent labeling of the cell wall (Ota and Kawano, 2015 ) and endomembrane (Laundon, unpublished) have shown increased relative brightness in the apophysis compared to the sporangium indicating elevated activity, however the structure and function of the apophysis is largely unknown. What is the role of the apophysis in aquatic chytrids, how is the apophysis formed and what does it contain?…”