Polish Contribution to Global Research on Somatic Embryogenesis

Somatic embryogenesis (SE) is a complex process that begins with regaining totipotency in some somatic cells, proceeds through embryo development and maturation, and ends with the formation of a whole plant. Since the first publications on SE in 1958, this regeneration process has been applied to the in vitro propagation of many plant species and has led to the development of some specific model systems. SE has been used to expand our understanding of the cytomorphological, physiological, biochemical, and genetic processes that govern the earliest developmental events in the life of plants. This paper summarizes the achievements of Polish research groups working on SE systems established for several plants (gentians, the tree fern Cyathea delgadii Sternb., and conifers) and three model species ( Arabidopsis thaliana , Medicago sativa , and M. truncatula ). SE systems have used a broad spectrum of experimental approaches involving genomic tools (transcriptomics, proteomics, and chromatin analyses), physiological methods which focus on phytohormones, and cytological techniques. Studies on the experimental models of A. thaliana and Medicago spp. have resulted in the identification of new genetic and epigenetic elements of the complex regulatory network controlling embryogenic induction in plant somatic cells. The protocol developed for ferns has provided a unique and simple system for cytological analysis of early SE events that occur in a single cell of initial explants. Gentian embryogenic suspension cultures have successfully been used in broad biotechnological applications, including plant transformation, protoplast isolation, culture, and fusion. Systems described for coniferous species effectively produced many vigorous somatic seedlings and cost-efficient storage of genotypes during clonal field-testing. The research undertaken by Polish scientists has resulted in developing experimental systems that have enabled significant advances in SE knowledge.