Unraveling somatic embryogenesis signaling pathways – the role of extracellular molecules as efficiency modulators

Abstract

Somatic embryogenesis (SE) can be described as a process involving the formation of structures similar to the zygotic embryos, arising from dedifferentiation of somatic cells and not requiring the occurrence of fertilization. This process, widely used in clonal propagation and genetic transformation of several plant species, is not routinely used in olive (Olea europaea sp. europaea L.), due to the recalcitrant behaviour that characterizes olive adult tissues. In fact, most of the protocols established for olive cultivars and wild olive genotypes, are based on tissues taken from zygotic embryos, which are characterized by high genetic variability. If adult tissues can be used, in vitro SE may be an interesting alternative for vegetative propagation of high agronomical interesting olive cultivars that exhibit a recalcitrant behaviour when propagation procedures requiring the formation of adventitious roots are used. An important factor referred as affecting SE in plants, but not yet receiving the necessary attention, and to the best of our knowledge, never considered in any olive study, is the release of organic bioactive molecules by the explants into the culture medium. These molecules are involved in several biological processes and can play an important role in cellular communications. Based on this knowledge, a new research line focused on the role of extracellular molecules and its involvement in efficient signalling of SE was started in olive, and here it will be presented: i) the different molecules that could be secreted to the culture medium during SE and its potential role in determining SE efficiency, ii) the approach that was defined in frame of this research line to identify biomarkers associated to SE efficiency using different OMIC approaches (transcriptomics, proteomics and metabolomics), iii) the strategy to evaluate the potential applicability of extracellular molecules to overcome recalcitrant behaviour upon SE stimulus.