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Global DNA methylation changes caused by in vitro conditions are associated with the subculturing and phenotypic variation in Agave angustifolia Haw. While the relationship between the development of albinism and in vitro culture is well documented, the role of epigenetic processes in this development leaves some important questions unanswered. During the micropropagation of Agave angustifolia Haw., we found three different phenotypes, green (G), variegated (V) and albino (A). To understand the physiological and epigenetic differences among the somaclones, we analyzed several morphophysiological parameters and changes in the DNA methylation patterns in the three phenotypes during their in vitro development. We found that under in vitro conditions, the V plantlets maintained their CAM photosynthetic capacity, while the A variant showed no pigments and lost its CAM photosynthetic ability. Epigenetic analysis revealed that global DNA methylation increased in the G phenotype during the first two subcultures. However, after that time, DNA methylation levels declined. This hypomethylation correlated with the appearance of V shoots in the G plantlets. A similar correlation occurred in the V phenotype, where an increase of 2 % in the global DNA methylation levels was correlated with the generation of A shoots in the V plantlets. This suggests that an "epigenetic stress memory" during in vitro conditions causes a chromatin shift that favors the generation of variegated and albino shoots.

Background: Cannabidiol (CBD), a non-psychotropic constituent of Cannabis sativa, has shown therapeutic promises by modulating several pathological conditions, including pain, epilepsy autism, among others. However, the molecular mechanism of action of CBD remains unknown and recent data suggest the engagement on CBD´s effects of nuclear elements, such as histone activity. Aim: This study assessed the changes on the post-translational modification (PTM) on the histones H3K4Me3, H3K9ac, H3K9Me2, H3K27Me3, and H3K36Me2 in several brain regions of rats after the administration of CBD (20mg/Kg/i.p.). Objective: To evaluate the effects on the PTM of histones H3K4Me3, H3K9ac, H3K9Me2, H3K27Me3, and H3K36Me2 levels in the cerebral cortex, hypothalamus and pons of CBD-treated rats. Method: Ten adult rats were randomly assigned into 2 groups: Control or CBD (20mg/Kg/i.p). Animals were sacrificed after treatments and brains were collected for dissections of the cerebral cortex, hypothalamus and pons. Samples were analyzed for PTM on the histones H3K4Me3, H3K9ac, H3K9Me2, H3K27Me3, and H3K36Me2 levels by Western blot procedure. Results: CBD increased the PTM levels on the histones H3K4Me3, H3K9ac, and H3K27Me3 in the cerebral cortex whereas no significant differences were found in H3K9Me2 and H3K36Me2. In addition, in the hypothalamus, CBD decreased the contents of H3K9ac while no significant effects were observed in H3K4Me3, H3K9Me2, H3K27Me3, and H3K36Me2. Lastly, in the pons, CBD-treated rats showed a significant decline on the PTM levels of H3K4Me3 whereas no statistical differences were found in H3K9ac, H3K9Me2, H3K27Me3, and H3K36Me2. Conclusion: The study showed that CBD induced differential effects in levels of PTM on the histones H3K4Me3, H3K9ac, H3K9Me2, H3K27Me3, and H3K36Me2 in several brain regions.

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