Can mosses serve as model organisms for forest research?

KEY MESSAGE : Based on their impact on many ecosystems, we review the relevance of mosses in research regarding stress tolerance, metabolism, and cell biology. We introduce the potential use of mosses as complementary model systems in molecular forest research, with an emphasis on the most developed model moss Physcomitrella patens. CONTEXT AND AIMS : Mosses are important components of several ecosystems. The moss P. patens is a well-established non-vascular model plant with a high amenability to molecular biology techniques and was designated as a JGI plant flagship genome. In this review, we will provide an introduction to moss research and highlight the characteristics of P. patens and other mosses as a potential complementary model system for forest research. METHODS : Starting with an introduction into general moss biology, we summarize the knowledge about moss physiology and differences to seed plants. We provide an overview of the current research areas utilizing mosses, pinpointing potential links to tree biology. To complement literature review, we discuss moss advantages and available resources regarding molecular biology techniques. RESULTS AND CONCLUSION : During the last decade, many fundamental processes and cell mechanisms have been studied in mosses and seed plants, increasing our knowledge of plant evolution. Additionally, moss-specific mechanisms of stress tolerance are under investigation to understand their resilience in ecosystems. Thus, using the advantages of model mosses such as P. patens is of high interest for various research approaches, including stress tolerance, organelle biology, cell polarity, and secondary metabolism.