Optimized surface decontamination of gametophores for axenic in vitro culture of the moss Warnstorfia sarmentosa (Wahlenb.) Hedenäs, with application to other polar mosses

Abstract Mosses are non-vascular plants widely distributed across multiple habitats and capable of thriving in extreme environments, such as Antarctica and the Arctic. However, knowledge of the genetic, metabolic, and molecular diversity of polar species remains limited, necessitating a better understanding of their mechanisms of response to harsh conditions. In this context, axenic in vitro cultivation under laboratory conditions is a powerful tool for plant sciences to elucidate physiological and biochemical responses. Nevertheless, in vitro cultivation of polar mosses can be challenging, as most species lack viable sporophytes or are predominantly sterile. Alternatively, gametophores can be used; however, many fail to withstand surface decontamination or are subsequently overrun by microorganisms. To establish an efficient and replicable decontamination method, we compared the efficacy of treatments applied to field‑collected gametophores from three sites and pre‑cultured leafy shoots of Warnstorfia sarmentosa (Wahlenb.) Hedenäs as a model species, using different concentrations of sodium dichloroisocyanurate (NaDCC) and sodium hypochlorite (NaClO). Explants derived from pre-cultured tissue achieved an overall success rate of 64.1%, compared with 12.7% for field-collected material, and success among field samples varied markedly across collection sites (0–28%). For pre-cultured material, NaDCC (0.1% and 0.5%) was more effective than NaClO (0.5% and 1%) ( p = 0.0309). This optimized method was subsequently applied to other species. Currently, 33 ecotypes from 12 polar moss species are successfully maintained under axenic conditions, providing a valuable resource for applications including stress tolerance studies, metabolite profiling, ex situ conservation of endangered taxa, and biotechnological exploitation.