Culture-based preservation of Marchantia polymorpha gemmalings and thalli without encapsulation, drying, or freezing

Ongoing research has generated many important lines of the model liverwort Marchantia polymorpha, including mutants and transgenic lines. To maintain these lines, researchers typically spend a lot of time and effort periodically replanting thalli (e.g., every month). To avoid this routine maintenance, researchers have developed methods for cryopreservation of dried and frozen gemmae. In this study, we developed a culture-based method for preserving gemmalings and thalli without encapsulation, drying, or freezing. The method requires only tissue culture on agar medium supplemented with sucrose in the dark at regular temperature (22°C). These culture conditions severely inhibit growth of gemmalings and thalli; however, these tissues remained alive after more than 1 year of storage. Survival rate of tissues using this method was 100% in all tests. This method thus enables preservation of gemmaling and thallus cultures on medium under regular temperature conditions, thereby relieving researchers of labor-intensive routine maintenance.