GSE185155
Transcriptomic Changes in Internode Explants of Stinging Nettle during Callogenesis
Callogenesis, the process during which explants derived from differentiated plant tissues are subjected to a de-differentiation step characterized by the proliferation of an unorganized mass of cells, is fundamental to indirect organogenesis and the establishment of cell suspension cultures. There-fore, understanding how callogenesis takes place is helpful to plant tissue culture, as well as to plant biotechnology and bioprocess engineering. The common herbaceous plant stinging nettle (Urtica dioica L.) is a species producing cellulosic fibres (the bast fibres) and a whole array of phytochemicals of pharmacological and cosmeceutical use. It is thus of interest as a potential multi-purpose plant. In this study, callogenesis in internode explants of a nettle fibre clone (clone 13) was studied using RNA-Seq to understand which gene ontologies predominate at different time points. Callogenesis was induced with the plant growth regulators a-napthaleneacetic acid (NAA) and 6-benzyl aminopurine (BAP) after having determined their optimal concentrations. The process was studied over a period of 34 days, time point at which a well visible callus mass developed on the explants. The bioinformatic analysis of the transcriptomic dataset revealed specific gene ontologies charac-terizing each of the four time points investigated (0, 1, 10 and 34 days-D). The results show that while the advanced stage of callogenesis is characterized by the iron deficiency response triggered by the high levels of reactive oxygen species accumulated by the proliferating cell mass, the intermediate and early phases are dominated by ontologies related to immune response and cell wall loosening, respectively. Overall design: Callogenesis study at different time points (0-1-10-34 days) in nettle internode explants incubazed on callus-inducing medium  supplemented with 3 mg/L NAA and 0.01 mg/L BAP in the dark.