Assessment of the recovery and photosynthetic efficiency of Breviolum psygmophilum and Effrenium voratum (Symbiodiniaceae) following cryopreservation

Joseph K Kihika; Susanna A Wood; Lesley Rhodes; Kirsty F Smith; Juliette Butler; Ken G Ryan

doi:10.7717/peerj.14885

Assessment of the recovery and photosynthetic efficiency of Breviolum psygmophilum and Effrenium voratum (Symbiodiniaceae) following cryopreservation

PeerJ. 2023 Feb 28:11:e14885. doi: 10.7717/peerj.14885. eCollection 2023.

Authors

Joseph K Kihika^{1

2}, Susanna A Wood², Lesley Rhodes², Kirsty F Smith^{2

3}, Juliette Butler², Ken G Ryan¹

Affiliations

¹ Department of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand.
² Cawthron Institute, Nelson, New Zealand.
³ Department of Biological Sciences, University of Auckland, Auckland, New Zealand.

Abstract

Many strains of Symbiodiniaceae have been isolated and their genetics, taxonomy, and metabolite production studied. Maintaining these cultures requires careful and regular sub-culturing that is costly with a high risk of species contamination or loss. Cryopreservation is a viable alternative for their long-term storage; however, there is uncertainty as to whether cryopreservation impacts the photosynthetic performance of Symbiodiniaceae. We investigated the growth rates and photosynthetic efficiency of two species, Breviolum psygmophilum and Effrenium voratum before and after cryopreservation. Rapid light curves (RLCs) produced using Pulse Amplitude Modulated (PAM) fluorometry were used to generate detailed information on the characteristics of photosystem II (PSII). The maximum electron transport rate (ETRmax) and the quantum yield (F_v/F_m) of the control (non-cryopreserved) and cryopreserved culture isolates were assessed across the growth cycle. The non-cryopreserved isolate of B. psygmophilum had a higher quantum yield than the cryopreserved isolate from day 12 to day 24, whereas there were no differences from day 28 to the late stationary phase. There were no significant differences in ETRmax. No significant differences were observed in quantum yield or ETRmax between the control and cryopreserved E. voratum isolates. The ability of cryopreserved strains to recover and regain their photosynthetic efficiency after freezing demonstrates the utility of this method for the long-term storage of these and other Symbiodiniaceae species.

Keywords: Control; Cryopreservation; Cryopreserved; Maximum electron transport rate; PAM fluorometry; Photosynthesis; Quantum yield; Rapid freezing; Rapid light curves; Symbiodiniaceae.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cell Cycle
Cryopreservation*
Dinoflagellida*
Electron Transport
Photosynthesis

Grants and funding

This research was supported by funding from the New Zealand Ministry of Business, Innovation and Employment, Contract number: CAWX0902 and a Cawthron Institute Internal Capability Investment Fund scholarship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.