Hypomethylation of cytosine residues in cold-sensitive regions of Cestrum strigilatum (Solanaceae)

heterochromatin comprises a fraction of the genome usually with highly repeated dna sequences and lacks of functional genes. this region can be revealed by using giemsa c-banding, fluorochrome staining and cytomolecular tools. some plant species are of particular interest through having a special type of heterochromatin denominated the cold-sensitive region (csr). independent of other chromosomal regions, when biological materials are subjected to low temperatures (about 0 °c), csrs appear slightly stained and decondensed. in this study, we used cestrum strigilatum (solanaceae) to understand some aspects of csr condensation associated with cytosine methylation levels, and to compare the behavior of different heterochromatin types of this species, when subjected to low temperatures.