In Vitro Proliferation and Genome DNA Methylation in Adult Chestnuts

Chestnut in vitro morphogenic competence was analyzed in shoot segments from the same adult trees but taken from branches with different ontogenetic development, juvenile-like and mature. During the establishment and the proliferation phases differences were quantified according to the ontogenic nature of the explants. Despite the establishment phase was successful for both juvenile-like and mature, mature ones needed additional handling to maintain its own multiplication lines. DNA methylation was analyzed in shoot apex from different growth and developmental situations. During the active growth juvenile-like tissues, without reproductive ability, showed a percentage of global DNA methylation of 23.0 percent while mature tissues, with reproductive ability, showed a lower level of methylated cytosines of 13.7 percent. Independently of explants origin, the 5-methydeoxicytosine (5mdC)percentages after one proliferation phase showed that both microshoot types arose to a common level of methylation (15.0 percent). Opposite to the active growth period, the dormancy phase was characterized by hypermethylation (35.0 percent). The possible nature of these results were analyzed.