Tissue culture-induced DNA methylation in crop plants: a review
Citation
Ghosh, A., Abir U. Igamberdiev, A.U. and Debnath, S.C. (2021). "Tissue culture-induced DNA methylation in crop plants: a review.", Molecular Biology Reports (https://doi.org/10.1007/s11033-020-06062-6).
Plain language summary
Plant tissue culture techniques (e.g., micropropagation) have been extensively used for multiplying plants year round. Tissue culture plants are not always identical to their respective mother plants. Due to the changed environment in tissue culture system, plants are exposed to stressors that cause variations to occur (e.g., tissue culture-induced variation or somaclonal variation). These variations can be genetic (regulated by a gene) or non-genetic (epigenetic). These variations may be due to DNA methylation (addition methyl groups to the DNA molecule), which modifies gene function and expression. Molecular techniques are available to detect DNA methylation. Here, we review various aspects of DNA methylation during micropropagation and its effect on crop improvement. Understanding the molecular basis of this variation will help to overcome the drawbacks of micropropagation and produce micropropagated plants similar to their respective mother plants.
Abstract
Plant tissue culture techniques have been extensively employed in commercial micropropagation to provide year-round production. Tissue culture regenerants are not always genotypically and phenotypically similar. Due to the changes in the tissue culture microenvironment, plant cells are exposed to additional stress which induces genetic and epigenetic instabilities in the regenerants. These changes lead to tissue culture-induced variations (TCIV) which are also known as somaclonal variations to categorically specify the inducing environment. TCIV includes molecular and phenotypic changes persuaded in the in vitro culture due to continuous sub-culturing and tissue culture-derived stress. Epigenetic variations such as altered DNA methylation pattern are induced due to the above-mentioned factors. Reportedly, alteration in DNA methylation pattern is much more frequent in the plant genome during the tissue culture process. DNA methylation plays an important role in gene expression and regulation of plant development. Variants originated in tissue culture process due to heritable methylation changes, can contribute to intra-species phenotypic variation. Several molecular techniques are available to detect DNA methylation at different stages of in vitro culture. Here, we review the aspects of TCIV with respect to DNA methylation and its effect on crop improvement programs. It is anticipated that a precise and comprehensive knowledge of molecular basis of in vitro-derived DNA methylation will help to design strategies to overcome the bottlenecks of micropropagation system and maintain the clonal fidelity of the regenerants.