Effect of in vitro shoot multiplication and somatic embryogenesis on 5-methylcytosine content in DNA of Myrtus communis L.

Reversed-phase HPLC analysis of 2'-deoxynucleosides was performed to study the amount of 5-methylcytosine in genornic DNA of Myrtus communis L. About 11% cytosines were found to be methylated in DNA of field growing shoots. T his amount showed no variation after the establishment of shoots in vitro o r their subsequent rooting and acclimatisation to ex vitro conditions. Ther efore, adult elite plants can be micropropagated and transferred to the fie ld without global DNA methylation changes. Likewise, no trend in 5-methylcy tosine content was introduced by increasing the number of subcultures in ei ther adult- or seedling-originated shoot stocks. On the other hand, no diff erence was found in DNA methylation after plant regeneration from embryogen ic calli. The significance of a tissue culture model system with no global hypo- or hypermethylation is discussed.