Plants possess remarkable capability to regenerate upon tissue damage or optimal environmental stimuli. This ability not only serves as a crucial strategy for immobile plants to survive through harsh environments, but also made numerous modern plant improvements techniques possible. At the cellular level, this biological process involves dynamic changes in gene expression that redirect cell fate transitions. It is increasingly recognized that chromatin epigenetic modifications, both activating and repressive, intricately interact to regulate this process. Moreover, the outcomes of epigenetic regulation on regeneration are influenced by factors such as the differences in regenerative plant species and donor tissue types, as well as the concentration and timing of hormone treatments. In this review, we focus on several well-characterized epigenetic modifications and their regulatory roles in the expression of widely studied morphogenic regulators, aiming to enhance our understanding of the mechanisms by which epigenetic modifications govern plant regeneration.

DNA methylation is a conserved epigenetic modification that is typically associated with silencing of transposable elements and promoter methylated genes. However, some DNA-methylated loci are protected from silencing, allowing transcriptional flexibility in response to environmental and developmental cues. Through a genetic screen in Arabidopsis (Arabidopsis thaliana), we uncovered an antagonistic relationship between the MICRORCHIDIA (MORC) protein and the IMITATION SWITCH (ISWI) complex in regulating the DNA-methylated SUPPRESSOR OF DRM1 DRM2 CMT3 (SDC) reporter. We demonstrate that components of the plant-specific ISWI complex, including CHROMATIN REMODELING PROTEIN11 (CHR11), CHR17, DDT-RELATED PROTEIN4 (DDR4), and DDR5, function to partially de-repress silenced genes and transposable elements (TEs), through their function in regulating nucleosome distribution. This action also requires the known transcriptional activator DNAJ proteins, providing a mechanistic link between nucleosome remodeling and transcriptional activation. Genome-wide studies revealed that DDR4 causes changes in nucleosome distribution at numerous loci, a subset of which is associated with changes in DNA methylation and/or transcription. Our work reveals a mechanism for balancing transcriptional flexibility and faithful silencing of DNA-methylated loci. As both ISWI and MORC family genes are widely distributed across plant and animal species, our findings may represent a conserved eukaryotic mechanism for fine-tuning gene expression under epigenetic regulation.

The main propagation approach is tissue culture in blueberries, and tissue culture is an effective and low-cost method with higher economic efficiency in blueberries. However, there is a lack of stable and efficient production systems of industrialization of tissue culture in blueberries. In this study, the high-efficiency tissue culture and rapid propagation technology system were established based on blueberry leaves and stems. The optimal medium for callus induction was WPM (woody plant medium) containing 2.0 mg/L Forchlorfenuron (CPPU), 0.2 mg/L 2-isopentenyladenine (2-ip) with a 97% callus induction rate and a callus differentiation rate of 71% by using blueberry leaves as explants. The optimal secondary culture of the leaf callus medium was WPM containing 3.0 mg/L CPPU with an increment coefficient of 24%. The optimal bud growth medium was WPM containing 1.0 mg/L CPPU, 0.4 mg/L 2-ip, with which the growth of the bud was better, stronger and faster. The optimal rooting medium was 1/2 Murashige and Skoog (1/2MS) medium containing 2.0 mg/L naphthylacetic acid (NAA), with which the rooting rate was 90% with shorter rooting time and more adventitious root. In addition, we established a regeneration system based on blueberry stems. The optimal preculture medium in blueberry stem explants was MS medium containing 2-(N-morpholino) ethanesulfonic acid (MES) containing 0.2 mg/L indole-3-acetic acid (IAA), 0.1 mg/L CPPU, 100 mg/L NaCl, with which the germination rate of the bud was 93%. The optimal medium for fast plant growth was MS medium containing MES containing 0.4 mg/L zeatin (ZT), 1 mg/L putrescine, 1 mg/L spermidine, 1 mg/L spermidine, which had a good growth state and growth rate. The optimal cultivation for plantlet growth was MS medium containing MES containing 0.5 mg/L isopentene adenine, with which the plantlet was strong. The optimal rooting medium for the stem was 1/2MS medium containing 2.0 mg/L NAA, with which the rooting rate was 93% with a short time and more adventitious root. In conclusion, we found that stem explants had higher regeneration efficiency for a stable and efficient production system of industrialization of tissue culture. This study provides theoretical guidance and technical support in precision breeding and standardization and industrialization in the blueberry industry.

In plants, the genome structure of hybrids changes compared with their parents, but the effects of these changes in hybrids remain elusive. Comparing reciprocal crosses between Col × C24 and C24 × Col in Arabidopsis using high‐throughput chromosome conformation capture assay (Hi‐C) analysis, we found that hybrid three‐dimensional (3D) chromatin organization had more long‐distance interactions relative to parents, and this was mainly located in promoter regions and enriched in genes with heterosis‐related pathways. The interactions between euchromatin and heterochromatin were increased, and the compartment strength decreased in hybrids. In compartment domain (CD) boundaries, the distal interactions were more in hybrids than their parents. In the hybrids of CURLY LEAF (clf) mutants clf_Col × clf_C24 and clf_C24 × clf_Col, the heterosis phenotype was damaged, and the long‐distance interactions in hybrids were fewer than in their parents with lower H3K27me3. ChIP‐seq data revealed higher levels of H3K27me3 in the region adjacent to the CD boundary and the same interactional homo‐trans sites in the wild‐type (WT) hybrids, which may have led to more long‐distance interactions. In addition, the differentially expressed genes (DEGs) located in the boundaries of CDs and loop regions changed obviously in WT, and the functional enrichment for DEGs was different between WT and clf in the long‐distance interactions and loop regions. Our findings may therefore propose a new epigenetic explanation of heterosis in the Arabidopsis hybrids and provide new insights into crop breeding and yield increase.

Modern maize stems possess a well‐developed vascular bundle system, which is critical for providing mechanical support and lodging resistance. However, characterization of the microanatomical features of vascular bundles and their functional implications in stem mechanics remains challenging, primarily due to technical limitations in high‐throughput microanatomical analysis of stem tissues. We thus constructed data sets consisting of over 500,000 maize stem CT images from a maize diversity panel of 383 inbred lines. We evaluated 32 microanatomical phenotypes of maize basal internodes across two environments in different years. By incorporating engineering mechanics parameters, we calculated novel characteristics of the vascular bundles, including the moment of area (MOA) and the polar moment of inertia (PMOI). Through the high‐density phenotypic data set, we identified multiple stem microanatomical phenotypes strongly associated with lodging resistance, particularly of vascular bundle mechanical traits. By integrating population genetic profiling, we discovered and confirmed that ZmLSM2 (U6 small nuclear ribonucleoprotein specific Sm‐like 2) serves as a key regulator of stem mechanical strength, might function in RNA processing and maturation within vascular stem cells, identifying novel genetic targets for improving maize lodging resistance. This approach demonstrates the value of combining advanced phenotyping with multi‐omics analyses for crop improvement. These discoveries will deepen the understanding of plant stem biomechanical principles and provide novel targets for enhancing lodging resistance in crop breeding programs.