Epigenetic Regulation of Auxin Homeostasis

Abstract

Epigenetic regulation involves a myriad of mechanisms that regulate the expression of loci without altering the DNA sequence. These different mechanisms primarily result in modifications of the chromatin topology or DNA chemical structure that can be heritable or transient as a dynamic response to environmental cues. The phytohormone auxin plays an important role in almost every aspect of plant life via gradient formation. Auxin maxima/minima result from a complex balance of metabolism, transport, and signaling. Although epigenetic regulation of gene expression during development has been known for decades, the specific mechanisms behind the spatiotemporal dynamics of auxin levels in plants are only just being elucidated. In this review, we gather current knowledge on the epigenetic mechanisms regulating the expression of genes for indole-3-acetic acid (IAA) metabolism and transport in Arabidopsis and discuss future perspectives of this emerging field.

Brassinosteroid Priming Improves Peanut Drought Tolerance via Eliminating Inhibition on Genes in Photosynthesis and Hormone Signaling

“…We propose that seed priming with BR will induce a memorized early defense response, which could be recalled and induce a fast response in later occurred stress. This could be via methylation mechanisms at the epigenetic level [ 10 ]. In addition, here the observed lower transpiration rates are also associated with BR priming under drought.…”

“…Epigenetic state, e.g., methylation, could affect the gene regulation in response to stress. For example, auxin homeostasis is epigenetically controlled [ 10 ].…”

Hypermethylation of Auxin-Responsive Motifs in the Promoters of the Transcription Factor Genes Accompanies the Somatic Embryogenesis Induction in Arabidopsis

“…The mechanism by which auxin might impact on DNA methylation to control gene expression includes the auxin-mediated regulation of the genes encoding the DNA (de)methylases, which are essential components of the epigenetic mechanism that controls developmental processes [ 69 , 80 , 81 , 82 ]. Similarly, the function of the DNA (de)methylases in auxin-induced embryogenic cultures of different plants, including Arabidopsis, has been postulated [ 6 , 7 , 50 , 83 , 84 , 85 ].…”

“…Understanding of the contribution of DNA methylation to the transcriptional regulation of the genes that control SE induction requires insights into the interactions of DNA methylation with the other epigenetic processes [ 81 , 82 , 149 ]. In Arabidopsis, several studies have provided support for a self-reinforcing loop between DNA and histone methylation, and the CMT2/CMT3 chromomethylases of DNA were found to contain binding sites for silencing the chromatin mark of H3K9me2 [ 149 ].…”

Auxin: Hormonal Signal Required for Seed Development and Dormancy

“…Thus, auxin plays a critical role in plant growth and development by forming local concentration gradients [ 61 ]. Therefore, local auxin synthesis and metabolism, intercellular transport (i.e., AUXIN1/LIKE-AUX1 family of auxin influx carriers (AUX/LAX), PIN-FORMED family of auxin efflux carriers (PIN; with eight members in Arabidopsis and four expressed during embryogenesis), and some members of P-GLYCOPROTEIN/ATP-BINDING CASSETTE B4 (ABCB/PGP) family carriers) and auxin signaling ( Figure 1 ), acting all in connection, will determine the gradient of auxins and tissue patterning [ 49 , 56 , 64 , 65 , 66 ]. Cellular localization of these carriers is indicative of the auxin flow direction, creating thus morphogenic auxin gradients.…”