Epigenetics in the modern era of crop improvements.

Epigenetic mechanisms are integral to plant growth, development, and adaptation to environmental stimuli. Over the past two decades, our comprehension of these complex regulatory processes has expanded remarkably, producing a substantial body of knowledge on both locus-specific mechanisms and genome-wide regulatory patterns. Studies initially grounded in the model plant Arabidopsis have been broadened to encompass a diverse array of crop species, revealing the multifaceted roles of epigenetics in physiological and agronomic traits.

DNA methylation remodeling and the functional implication during male gametogenesis in rice.

Background: Epigenetic marks are reprogrammed during sexual reproduction. In flowering plants, DNA methylation is only partially remodeled in the gametes and the zygote. However, the timing and functional significance of the remodeling during plant gametogenesis remain obscure.

Lysine acetylation of histone acetyltransferase adaptor protein ADA2 is a mechanism of metabolic control of chromatin modification in plants.

Histone acetylation is a predominant active chromatin mark deposited by histone acetyltransferases (HATs) that transfer the acetyl group from acetyl coenzyme A (acetyl-CoA) to lysine ε-amino groups in histones. GENERAL CONTROL NON-REPRESSED PROTEIN 5 (GCN5) is one of the best-characterized HATs and functions in association with several adaptor proteins such as ADA2 within multiprotein HAT complexes. ADA2-GCN5 interaction increases GCN5 binding to acetyl-CoA and stimulates its HAT activity.

Paternal DNA methylation is remodeled to maternal levels in rice zygote.

Epigenetic reprogramming occurs during reproduction to reset the genome for early development. In flowering plants, mechanistic details of parental methylation remodeling in zygote remain elusive. Here we analyze allele-specific DNA methylation in rice hybrid zygotes and during early embryo development and show that paternal DNA methylation is predominantly remodeled to match maternal allelic levels upon fertilization, which persists after the first zygotic division.

A DNA adenine demethylase impairs PRC2-mediated repression of genes marked by a specific chromatin signature.

Background: The Fe (II)- and α-ketoglutarate-dependent AlkB family dioxygenases are implicated in nucleotide demethylation. AlkB homolog1 (ALKBH1) is shown to demethylate DNA adenine methylation (6mA) preferentially from single-stranded or unpaired DNA, while its demethylase activity and function in the chromatin context are unclear.

Results: Here, we find that loss-of-function of the rice ALKBH1 gene leads to increased 6mA in the R-loop regions of the genome but has a limited effect on the overall 6mA level.

ACL and HAT1 form a nuclear module to acetylate histone H4K5 and promote cell proliferation.

Acetyl-CoA utilized by histone acetyltransferases (HAT) for chromatin modification is mainly generated by ATP-citrate lyase (ACL) from glucose sources. How ACL locally establishes acetyl-CoA production for histone acetylation remains unclear. Here we show that ACL subunit A2 (ACLA2) is present in nuclear condensates, is required for nuclear acetyl-CoA accumulation and acetylation of specific histone lysine residues, and interacts with Histone AcetylTransferase1 (HAT1) in rice.

A Chromodomain-Helicase-DNA-Binding Factor Functions in Chromatin Modification and Gene Regulation.

Proteins in the Chromodomain-Helicase/ATPase-DNA-binding domain (CHD) family are divided into three groups. The function of group I CHD proteins in nucleosome positioning is well established, while that of group II members (represented by CHD3/Mi2) remains unclear. Using high-throughput approaches, we investigated the function of the group II rice () CHD protein CHR729 in nucleosome positioning, gene expression, histone methylation, and binding.