DNA methylation of embryogenic carrot cell cultures and its variations as caused by mutation, differentiation, hormones and hypomethylating drugs

Abstract

The level of auxin - both natural and synthetic - in the medium has a strong effect on the level of 5-methyl-cytosine in the DNA of carrot cells in culture. This level may vary from approximately 15% to 70% of total cytosine without apparent effects on growth rate and cell morphology. No effect was seen with cytokinin. During somatic embryogenesis, in the absence of hormones, variations were seen in the level of methylation according to a characteristic pattern. If hypomethylation is induced with drugs such as azacytidine, ethionine or ethoxy-carbonyl-pyrimidine, embryogenesis is immediately blocked. A mutant was isolated which is resistant to the action of hypomethylating drugs. It shows variations in the methylation pattern and variations in indole-acetic acid metabolism. In addition its regeneration is often associated with the production of tumors.

Effect of carbon source on morphology and histodifferentiation of Araucaria angustifolia embryogenic cultures

“…According to Zoglauer (2003), during the induction phase, cells cease their program of specialization and start a new developmental program. The specialization program is negatively affected by the methylation of DNA for which the auxins may play a fundamental role (Lo Schiavo et al, 1989). The carbon source and plant growth regulators supplemented to the culture medium significantly affected the embryogenic induction rate.…”

Cell Culture-Induced Gradual and Frequent Epigenetic Reprogramming of Invertedly Repeated Tobacco Transgene Epialleles

“…Also, less differentiated cells contain a lower degree of methylation than fully differentiated mature leaf (Mathieu et al, 2003). It is not certain whether cells with highly methylated DNA are favored for regeneration and selected or whether hormonal factors (LoSchiavo et al, 1989) associated with the regeneration process increase overall genomic methylation.…”

Molecular aspects of somatic-to-embryogenic transition in plants

“…The LEC1 gene of Arabidopsis thaliana encodes a protein related to the Heme-Activated Proteins 3 (HAP3) subunit of the CCAAT box-Binding F LRR-RLKs actor (CBF) [102,110]. Kwong et al [101] identified genes encoding Arabidopsis HAP3 subunits in Phaseolus coccineus.…”