The epigenetic and physiologic changes as a trigger for indirect somatic embryogenesis in Coffea canephora

• Autor(a) principal: Silva, Paulo Marcos Amaral
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/13349
• topic: Melhoramento Vegetal; 5-metilcitosina; Coffea; Cultura de tecidos vegetais; Fitohormônios; Poliaminas; Regeneração in vitro; Phytohormones; Plant tissue culture; Polyamines; In vitro regeneration; subject.br-rjbn

Indirect somatic embryogenesis (ISE) establishment for Coffea species started in the 1970s. Since then, intraspecific variations in the morphogenic pathway have been reported, despite the meticulous standardization of the environmental conditions in vitro. Several authors have suggested that these variations are the result of genetic, epigenetic and/or physiological events, highlighting the need for investigations to know the respective causes. Along these lines, this study aimed to investigate and describe, for the first time, the changes in and influence of epigenetic and physiological aspects during cell proliferation and somatic embryo regeneration from cell aggregate suspensions of Coffea canephora. The cell proliferation step was characterized by increase in cell mass in all subcultures; relatively low mean values of global 5-methylcytosine (5-mC%), abscisic acid (ABA) and indole-3-acetic acid (IAA); high mean value of 1-aminocyclopropane 1-carboxylic acid (ACC, an ethylene precursor); and increases followed by decreases in spermidine (Spd, a polyamine) levels. With regard to the in vitro conditions, these aspects promoted the cell proliferation, showing that the epigenome and metabolome are fundamental for the first morphogenic moment of ISE. In turn, the second ISE moment is correlated with epigenetic and physiological changes. The competence acquisition, determination and cell differentiation steps were marked by increases in mean values of 5-mC%, IAA and ABA and decreases in ACC and Spd, evincing that these epigenetic and physiological changes are the triggers for regeneration and maturation of somatic embryos. Therefore, dynamic and coordinated epigenetic and physiological changes directly affect the two morphogenic moments of C. canephora ISE.