Revisiting the Life Cycle of Margalefidinium polykrikoides Group III

Authors

• Eduardo Pérez-Vega, Old Dominion University
• Kenneth N. Mertens, Ifremer, COAST
• Pjotr Meyvisch, Johns Hopkins University
• Margaret R. Mulholland, Old Dominion UniversityFollow

Document Type

Article

Publication Date

2026

DOI

10.1111/jpy.70201

Publication Title

Journal of Phycology

Volume

Advance online publication

Pages

1-16

Abstract

Dinoflagellates produce cysts as a strategy to withstand environmental stressors, with nutrient depletion generally considered a key trigger for cyst production. Resting cysts are thick-walled, typically composed of one to several layers, and characterized by a prolonged dormancy period. In contrast, pellicle cysts possess a thin, single wall and exhibit no dormancy or a markedly shorter dormancy than resting cysts of the same species. Margalefidinium polykrikoides produces pellicle and resting cysts, whereas its congener, M. fulvescens, has been shown to produce pumpkin-like structures. Using phase-contrast microscopy, time-lapse microscopy, FlowCam, and attenuated total reflection Fourier transform infrared microspectroscopy (ATR μ-FTIR), we investigated the environmental triggers of sac production, the role of the sacs in the life cycle of the M. polykrikoides American/Malaysian ribotype (Group III) strain, and the chemical composition of the sacs. The sacs observed here differed from pellicle cysts described in M. polykrikoides Group III NY and Group I Korea strains but were indistinguishable from the pumpkin-like structures of M. fulvescens. Phosphate depletion of the culture medium was determined as the main trigger for sac production. Sacs were produced through both sexual and asexual processes. We report the presence of sac transporters-diploid cells that facilitate sac movement. The ATR μ-FTIR data indicated that the sacs were primarily composed of sulfated polysaccharides, closely resembling the extracellular polymeric substances produced by M. polykrikoides (Japan strain) and by Gymnodinium sp. Based on their single thin wall and absence of dormancy, these sacs are considered pellicle cysts.

Rights

© 2026 The Authors

This is an open access article under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Original Publication Citation

Pérez-Vega, E., Mertens, K. N., Meyvisch, P., & Mulholland, M. R. (2026). Revisiting the life cycle of Margalefidinium polykrikoides Group III. Journal of Phycology. Advance online publication. https://doi.org/10.1111/jpy.70201

Repository Citation

Pérez-Vega, Eduardo; Mertens, Kenneth N.; Meyvisch, Pjotr; and Mulholland, Margaret R., "Revisiting the Life Cycle of Margalefidinium polykrikoides Group III" (2026). OES Faculty Publications. 581.
https://digitalcommons.odu.edu/oeas_fac_pubs/581