Initiation of leaf somatic embryogenesis involves high pectin esterification, auxin accumulation and DNA demethylation in Quercus alba

• Published in: Journal of plant physiology 2017-06, Vol.213, p.42-54
• Main Authors: Corredoira, Elena, Cano, Vanesa, Bárány, Ivett, Solís, María-Teresa, Rodríguez, Héctor, Vieitez, Ana-María, Risueño, María C., Testillano, Pilar S.
• Format: Article
• Language: English
• Subjects: Accumulation; Auxin; Cell reprogramming; Cell totipotency; Cell wall; Cell Wall - genetics; Cell Wall - metabolism; Demethylation; Deoxyribonucleic acid; DNA; DNA methylation; DNA Methylation - genetics; DNA Methylation - physiology; Embryology; Embryonic growth stage; Esterification; Gene Expression Regulation, Plant - genetics; Gene Expression Regulation, Plant - physiology; In vitro methods and tests; Indoleacetic Acids - metabolism; Leaf in vitro culture; Leaves; Markers; Oak; Pectin; Pectin esterification; Pectins - metabolism; Plant breeding; Plant Leaves - embryology; Plant Leaves - genetics; Plant Leaves - metabolism; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Somatic Embryogenesis Techniques; Quercus - embryology; Quercus - genetics; Quercus - metabolism; Quercus alba; Regeneration; Somatic embryogenesis; Trees; White oak; Wood
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1016/j.jplph.2017.02.012

Somatic embryogenesis is considered a convenient tool for investigating the regulating mechanisms of embryo formation; it is also a feasible system for in vitro regeneration procedures, with many advantages in woody species. Nevertheless, trees have shown recalcitrance to somatic embryogenesis, and its efficiency remains very low in many cases. Consequently, despite the clear potential of somatic embryogenesis in tree breeding programs, its application is limited since factors responsible for embryogenesis initiation have not yet been completely elucidated. In the present work, we investigated key cellular factors involved in the change of developmental program during leaf somatic embryogenesis initiation of white oak (Quercus alba), aiming to identify early markers of the process. The results revealed that pectin esterification, auxin accumulation and DNA demethylation were induced during embryogenesis initiation and differentially found in embryogenic cells, while they were not present in leaf cells before induction or in non-embryogenic cells after embryogenesis initiation. These three factors constitute early markers of leaf embryogenesis and represent processes that could be interconnected and involved in the regulation of cell reprogramming and embryogenesis initiation. These findings provide new insights into the mechanisms underlying plant cell reprogramming, totipotency and embryogenic competence acquisition, especially in tree species for which information is scarce, thus opening up the possibility of efficient manipulation of somatic embryogenesis induction.