The role of chromatin modifications in somatic embryogenesis in plants

Abstract

Somatic embryogenesis (SE) is a powerful tool for plant genetic improvement when used in combination with traditional agricultural techniques, and it is also an important technique to understand the different processes that occur during the development of plant embryogenesis. SE onset depends on a complex network of interactions among plant growth regulators, mainly auxins and cytokinins, during the proembryogenic early stages, and ethylene and gibberellic and abscisic acids later in the development of the somatic embryos. These growth regulators control spatial and temporal regulation of multiple genes in order to initiate change in the genetic program of somatic cells, as well as moderating the transition between embryo developmental stages. In recent years, epigenetic mechanisms have emerged as critical factors during SE. Some early reports indicate that auxins and in vitro conditions modify the levels of DNA methylation in embryogenic cells. The changes in DNA methylation patterns are associated with the regulation of several genes involved in SE, such as WUS, BBM1, LEC, and several others. In this review, we highlight the more recent discoveries in the understanding of the role of epigenetic regulation of SE. In addition, we include a survey of different approaches to the study of SE, and new opportunities to focus SE studies.

Analysis of Two Clonal Lines (Embryogenic and Non-Embryogenic) of <i>Agave fourcroydes</i> Using AFLP and MSAP

“…Different studies show that epigenetic changes might be related to totipotency acquisition, cellular reprogramming, induction of SE, and embryo development [2] [15] [61]. In this work, we observed that both clonal lines showed different genetic and epigenetic patterns before beginning the induction process (even when using the same explant).…”

A transcriptional view on somatic embryogenesis

“…These data indicate that histone deacetylation is a conserved mechanism in plants to repress embryo identity outside the seed. Similar to H3K27me3, levels of histone acetylation and the activity of HDACs has also been found to change after hormone‐induced indirect SE (De‐la‐Peña, Nic‐Can, Galaz‐Ávalos, Avilez‐Montalvo, & Loyola‐Vargas, 2015; Lee, Park, Jung, & Seo, 2016), providing indirect evidence that histone deacetylation may also play a role in the reprogramming of cells in the early stages of indirect SE.…”

“…The extent to which chromatin reprogramming is required prior to SE probably depends on the explant and culture system in which SE is induced, and might also require additional chromatin modifications such as changes in DNA methylation, which are often associated with SE (De‐la‐Peña et al., 2015). Direct SE appears to involve less reprogramming than indirect SE and probably occurs in cells where totipotency genes are transcriptionally accessible.…”

Somatic Embryogenesis. An Overview

“…8). There is an epigenetic reprogramming during the SE and the presence of somaclonal variation among the regenerated plants ( De-la-Peña et al 2015;Mahdavi-Darvari et al 2015;Nic-Can et al 2015;Solís et al 2015). This variation can be the result of chromosomal aberrations, genetic alterations, epigenetic regulations, and transposable elements.…”