Characterization and Stress Response of the JmjC Domain-Containing Histone Demethylase Gene Family in the Allotetraploid Cotton Species Gossypium hirsutum

Genome-wide identification and expression analysis reveal the role of histone methyltransferase and demethylase genes in heat stress response in potato (Solanum tuberosum L.)

BACKGROUND

Potato (Solanum tuberosum L.), the third most important non-cereal crop, is sensitive to high temperature. Histone modifications have been known to regulate various abiotic stress responses. However, the role of histone methyltransferases and demethylases remain unexplored in potato under heat stress.

METHODS

Potato genome database was used for genome-wide analysis of StPRMT and StHDMA gene families, which were further characterized by analyzing gene structure, conserved motif, domain organization, sub-cellular localization, promoter region and phylogenetic relationships. Additionally, expression profiling under high-temperature stress in leaf and stolon tissue of heat contrasting potato genotypes was done to study their role in response to high temperature stress.

RESULTS

The genome-wide analysis led to identification of nine StPRMT and eleven StHDMA genes. Structural analysis, including conserved motifs, exon/intron structure and phylogenetic relationships classified StPRMT and StHDMA gene families into two classes viz. Class I and Class II. A variety of cis-regulatory elements were explored in the promoter region associated with light, developmental, hormonal and stress responses. Prediction of sub-cellular localization of StPRMT proteins revealed their occurrence in nucleus and cytoplasm, whereas StHDMA proteins were observed in different sub-cellular compartments. Furthermore, expression profiling of StPRMT and StHDMA gene family members revealed genes responding to heat stress. Heat-inducible expression of StPRMT1, StPRMT3, StPRMT4 and StPRMT5 in leaf and stolon tissues of HS and HT cultivar indicated them as probable candidates for enhancing thermotolerance in potato. However, StHDMAs responded dynamically in leaf and stolon tissue of heat contrasting genotypes under high temperature.

CONCLUSION

The current study presents a detailed analysis of histone modifiers in potato and indicates their role as an important epigenetic regulators modulating heat tolerance.

GENERAL SIGNIFICANCE

Understanding epigenetic mechanisms underlying heat tolerance in potato will contribute towards breeding of thermotolerant potato varieties.

Genome-wide Characterization of the JmjC Domain-Containing Histone Demethylase Gene Family Reveals GhJMJ24 and GhJMJ49 Involving in Somatic Embryogenesis Process in Cotton

The Jumonji C (JmjC) domain-containing protein family, an important family of histone demethylase in plants, can directly reverse histone methylation and play important roles in various growth and development processes. In the present study, 51 JmjC genes (GhJMJs) were identified by genome-wide analysis in upland cotton (Gossypium hirsutum), which can be categorized into six distinct groups by phylogenetic analysis. Extensive syntenic relationship events were found between G. hirsutum and Theobroma cacao. We have further explored the putative molecular regulatory mechanisms of the JmjC gene family in cotton. GhJMJ24 and GhJMJ49 were both preferentially expressed in embryogenic callus compared to nonembryogenic callus in cotton tissue culture, which might be regulated by transcription factors and microRNAs to some extent. Further experiments indicated that GhJMJ24 and GhJMJ49 might interact with SUVH4, SUVH6, DDM1, CMT3, and CMT1 in the nucleus, potentially in association with demethylation of H3K9me2. Taken together, our results provide a foundation for future research on the biological functions of GhJMJ genes in cotton, especially in somatic embryogenesis in cotton tissue culture, which is crucial for the regeneration of transgenic plants.

Evolutionary History and Functional Diversification of the JmjC Domain-Containing Histone Demethylase Gene Family in Plants

Histone demethylases containing JumonjiC (JmjC) domains regulate gene transcription and chromatin structure by changing the methylation status of lysine residues and play an important role in plant growth and development. In this study, a total of 332 JmjC family genes were identified from 21 different plant species. The evolutionary analysis results showed that the JmjC gene was detected in each species, that is, the gene has already appeared in algae. The phylogenetic analysis showed that the KDM3/JHDM2 subfamily genes may have appeared when plants transitioned from water to land, but were lost in lycophytes (Selaginella moellendorffii). During the evolutionary process, some subfamily genes may have been lost in individual species. According to the analysis of the conserved domains, all of the plant JmjC genes contained a typical JmjC domain, which was highly conserved during plant evolution. The analysis of cis-acting elements showed that the promoter region of the JmjC gene was rich in phytohormones and biotic and abiotic stress-related elements. The transcriptome data analysis and protein interaction analyses showed that JmjC genes play an important role in plant growth and development. The results clarified the evolutionary history of JmjC family genes in plants and lay the foundation for the analysis of the biological functions of JmjC family genes.

Genome-wide identification, classification, and expression analysis of the JmjC domain-containing histone demethylase gene family in birch

BACKGROUND

Histone methylation occurs primarily on lysine residues and requires a set of enzymes capable of reading, writing, and erasing to control its establishment and deletion, which is essential for maintaining chromatin structure and gene expression. Histone methylation and demethylation are contributed to plant growth and development, and are involved in adapting to environmental stresses. The JmjC domain-containing proteins are extensively studied for their function in histone lysine demethylation in plants, and play a critical role in sustaining histone methylation homeostasis.

RESULTS

In this study, a total of 21 JmjC domain-containing histone demethylase proteins (JHDMs) in birch were identified and classified into five subfamilies based on structural characteristics and phylogenetic relationships among Arabidopsis, rice, maize, and birch. Although the BpJMJ genes displayed significant schematic variation, their distribution on the chromosomes is relatively uniform. Additionally, the BpJMJ genes in birch have never experienced a tandem-duplication event proved by WGD analysis and were remaining underwent purifying selection (Ka/Ks < < 1). A typical JmjC domain was found in all BpJMJ genes, some of which have other essential domains for their functions. In the promoter regions of BpJMJ genes, cis-acting elements associated with hormone and abiotic stress responses were overrepresented. Under abiotic stresses, the transcriptome profile reveals two contrasting expression patterns within 21 BpJMJ genes. Furthermore, it was established that most BpJMJ genes had higher expression in young tissues under normal conditions, with BpJMJ06/16 having the highest expression in germinating seeds and participating in the regulation of BpGA3ox1/2 gene expression. Eventually, BpJMJ genes were found to directly interact with genes involved in the "intracellular membrane" in respond to cold stress.

CONCLUSIONS

The present study will provide a foundation for future experiments on histone demethylases in birch and a theoretical basis for epigenetic research on growth and development in response to abiotic stresses.