N⁶-methyladenosine (m⁶A) is essential for RNA metabolism in cells. The YTH domain, conserved in the kingdom of Eukaryotes, acts as an m⁶A reader that binds m⁶A-containing RNA. In plants, the YTH domain is involved in plant hormone signaling, stress response regulation, RNA stability, translation, and differentiation. However, little is known about the YTH genes in tea-oil tree, which can produce edible oil with high nutritional value. This study aims to identify and characterize the YTH domains within the tea-oil tree (Camellia chekiangoleosa Hu) genome to predict their potential role in development and stress regulation. In this study, 10 members of the YTH family containing the YTH domain named CchYTH1-10 were identified from C. chekiangoleosa. Through analysis of their physical and chemical properties and prediction of subcellular localization, it is known that most family members are located in the nucleus and may have liquid–liquid phase separation. Analysis of cis-acting elements in the CchYTH promoter region revealed that these genes could be closely related to abiotic stress and hormones. The results of expression profiling show that the CchYTH genes were differentially expressed in different tissues, and their expression levels change under drought stress. Overall, these findings could provide a foundation for future research regarding CchYTHs in C. chekiangoleosa and enrich the world in terms of epigenetic mark m⁶A in forest trees.

Phenylpropanoids are crucial for the growth and development of plants and their interaction with the environment. As key transcriptional regulators of plant growth and development, MYB-like transcription factors play a vital role in the biosynthesis of phenylpropanoid metabolites. In this study, we functionally characterized PmMYB6, a Pinus massoniana gene that encodes an R2R3-MYB transcription factor. It was confirmed by qPCR that PmMYB6 was highly expressed in the flowers, xylem, and phloem of P. massoniana. By overexpressing PmMYB6 in tobacco and poplar, we found that transgenic plants had enlarged xylem, increased content of lignin and flavonoids, and up-regulated expression of several enzyme genes of the phenylpropane metabolism pathway to different degrees. The above research results indicate that PmMYB6 is involved in the metabolic flux distribution of different branches of the phenylpropane metabolic pathway, and the results may provide clues for the regulation of metabolic fluxes between flavonoids and the lignin biosynthesis pathways of P. massoniana, as well as provide a basis for the molecular breeding of P. massoniana.

N⁶-methyladenosine (m⁶A) is becoming one of the most important RNA modifications in plant growth and development, including defense, cell differentiation, and secondary metabolism. YT521-B homology (YTH) domain-containing RNA-binding proteins, identified as m⁶A readers in epitranscriptomics, could affect the fate of m⁶A-containing RNA by recognizing and binding the m⁶A site. Therefore, the identification and study of the YTH gene family in Liriodendron chinense (L. chinense) can provide a molecular basis for the study of the role of m⁶A in L. chinense, but studies on the YTH gene in L. chinense have not been reported. We identified nine putative YTH gene models in the L. chinense genome, which can be divided into DF subgroups and DC subgroups. Domain sequence analysis showed that the LcYTH protein had high sequence conservation. A LcYTH aromatic cage bag is composed of tryptophan and tryptophan (WWW). PrLDs were found in the protein results of YTH, suggesting that these genes may be involved in the process of liquid–liquid phase separation. LcYTH genes have different tissue expression patterns, but the expression of LcYTHDF2 is absolutely dominant in all tissues. In addition, the expression of the LcYTH genes is changed in response to ABA and MeJA. In this study, We identified and analyzed the expression pattern of LcYTH genes. Our results laid a foundation for further study of the function of the LcYTH gene and further genetic and functional analyses of m⁶A RNA modification in forest trees.

N⁶-methyladenosine (m⁶A) RNA modification is the most prevalent form of RNA methylation and plays a crucial role in plant development. However, our understanding of m⁶A modification in Masson pine (Pinus massoniana Lamb.) remains limited. In this study, a complete analysis of m⁶A writers, erasers, and readers in Masson pine was performed, and 22 m⁶A regulatory genes were identified in total, including 7 m⁶A writers, 7 m⁶A erases, and 8 readers. Phylogenetic analysis revealed that all m⁶A regulators involved in Masson pine could be classified into three distinct groups based on their domains and motifs. The tissue expression analysis revealed that the m⁶A regulatory gene may exert a significant influence on the development of reproductive organs and leaves in Masson pine. Moreover, the results from stress and hormone expression analysis indicated that the m⁶A regulatory gene in Masson pine might be involved in drought stress response, ABA-signaling-pathway activation, as well as resistance to Monochamus alternatus. This study provided valuable and anticipated insights into the regulatory genes of m⁶A modification and their potential epigenetic regulatory mechanisms in Masson pine.

N⁶-methyladenosine (m⁶A) is one of the most abundant chemical modifications on mRNA in eukaryotes. RNA-binding proteins containing the YT521-B (YTH) domain play crucial roles in post-transcriptional regulation of plant growth, development, and stress response by reading the m⁶A mark. However, the YTH domain-containing RNA-binding protein family has not been studied in a valuable and medicinal tree such as Cinnamomum camphora (C. camphora) yet. In this study, we identified 10 YTH genes in C. camphora, located on eight out of 12 chromosomes. Phylogenetic analysis revealed that these genes can be classified into two major classes, YTHDF (CcDF) and YTHDC (CcDC). Closely related CcYTHs within the same class exhibited a similar distribution of conserved motifs and domain organization, suggesting functional similarities among these closely related CcYTHs. All CcYTH proteins possessed a highly conserved YTH domain, with CcDC1A containing an additional CCCH domain. The liquid–liquid phase separation (LLPS) predictions indicate that CcDC1A, CcDF1A, CcDF1C, CcDF3C, CcDF4C, and CcDF5C may undergo phase transitions. Quantitative expression analysis revealed that tissue-specific expression was observed fo CcYTHs. Notably, there were two genes, CcDF1A and CcDF5C; both exhibited significantly higher expression levels in various tissues than other genes, indicating that the m⁶A-YTH regulatory network in C. camphora might be quite distinct from that in most plants such as Arabidopsis thaliana (A. thaliana) with only one abundant YTH protein. According to the analysis of the up-stream cis-regulatory elements of these YTH genes, these genes could be closely related to stress, hormones, and development. The following stress response experiments further verified that their expression levels indeed changed under both PEG and NaCl treatments. These findings not only provide a foundation for future functional analysis of CcYTHs in C. camphora, but also provide insights into the functions of epigenetic mark m⁶A in forest trees.

Stress-associated proteins (SAPs), belonging to the A20/AN1 zinc finger protein family, are key regulators in plant stress responses. Despite their importance, studies on the SAP gene family in Pinus massoniana are still relatively scarce. This study aimed to systematically identify and characterize SAP genes in P. massoniana and to explore their potential roles in stress response mechanisms. A total of 17 PmSAP genes were identified from P. massoniana. Phylogenetic analysis revealed that these genes group into five distinct clades, and 10 conserved motifs were identified. Using transcriptome data and qRT-PCR, we analyzed their expression patterns and employed yeast systems to validate their transcriptional activities. The responses of PmSAP gene family members to different stress treatments showed significant differences. For example, PmSAP8 and PmSAP12 responded strongly to ABA, MeJA, and H₂O₂ treatments, while PmSAP3 and PmSAP5 showed significant upregulation under ETH and NaCl stress. Yeast experiments indicated that PmSAP6/8/12 were transcriptional activators, and PmSAP3 and PmSAP5 were transcriptional suppressors. The identification and preliminary analysis of PmSAP genes provided a theoretical foundation for understanding stress resistance mechanisms in P. massoniana.