The plant-specific NAC transcription factor family has the largest number of members, they are involved in regulating the entire process of plant growth and development, and the responses to biotic and abiotic stressors. This article reviews the progress regarding the elucidation of the structure and function of the NAC transcription factor family and the regulatory mechanisms through which NAC transcription factors affect various processes in woody plants, including the formation of the secondary cell wall, seed development, flowering, and fruit ripening. Additionally, this article encompasses the current research status of NAC transcription factors in response to abiotic stressors, such as salt and drought, as well as biotic stressors, such as pathogens and pests in woody plants. Most of the research is still at the stages of gene cloning, structural identification, and functional analysis; the specific downstream target genes and their molecular mechanisms remain unclear. Future research should focus on exploring unknown functions and action mechanisms, to promote an understanding of the regulatory network of NAC transcription factors in woody plants, thereby providing a theoretical basis and gene resources for research on NAC transcription factors and the creation of new forest germplasm.

Mongolian oak (Quercus mongolica) is a common building material and landscaping tree species in northern China, with significant economic and ecological value. Its seedling growth is inhibited by high light intensity, but the mechanism by which light stress affects the growth and development of its seedlings remains unclear. In this study, we investigated the phenotypes, physiological processes, and molecular responses of 3-year-old Mongolian oak seedlings under different light treatments: full light (Sck), light shading (S1; 40% light), moderate shading (S2; 20% light), and severe shading (S3; 3% light). Compared to Sck, the S1 and S2 treatments resulted in higher leaf area, photosynthetic pigment content, photosynthesis rates, soluble sugar contents, and soluble protein contents in Mongolian oak seedlings. The S1 and S2 treatments also promoted seedling height and diameter growth and resulted in lower degrees of membrane lipid peroxidation, cell membrane permeability, and antioxidant enzyme activity. In contrast, severe shading (S3) significantly inhibited seedling height and diameter growth due to the lower net photosynthetic rate, and exhibiting higher degrees of membrane lipid peroxidation and cell membrane permeability. Shading treatments (S1 and S2) alleviated the negative effects of strong light on the growth and development of Mongolian oak seedlings, with the S2 treatment having the greatest effect. However, severe shading (S3) inhibited growth and development. A total of 3726 differentially expressed genes (DEGs) were detected in leaves under different shading treatments in RNA sequencing analysis. Among these, 1691, 3150, and 824 DEGs were detected in the Sck-S1, Sck-S2, and S1-S2 comparison groups, respectively. The different shading treatments determined common expression regulation pathways, including carotenoid biosynthesis, photosynthetic antenna proteins, and mitogen activated protein kinase (MAPK) signal transduction. Shading induced increases in gene expression levels in light harvesting complexes, which are related to changes in gene expression in the photosynthetic system, leading to changes in photosynthetic physiology. The expression levels of genes related to reactive oxygen species signal perception and activation enzymes were upregulated in Sck. Together, these findings revealed the response mechanisms of Mongolian oak seedlings to different shading levels at the physiological and molecular levels, providing a scientific basis and technical support for the cultivation and large-scale production of Mongolian oak seedlings.

Euonymus japonicus Beihaidao is one of the most economically important ornamental species of the Euonymus genus. There are approximately 97 genera and 1194 species of plants worldwide in this family (Celastraceae). Using E. japonicus Beihaidao, we conducted a preliminary study of the cold resistance of this species, evaluated its performance during winter, assembled and annotated its chloroplast genome, and performed a series of analyses to investigate its gene structure GC content, sequence alignment, and nucleic acid diversity. Our objectives were to understand the evolutionary relationships of the genus and to identify positive selection genes that may be related to adaptations to environmental change. The results indicated that E. japonicus Beihaidao leaves have certain cold resistance and can maintain their viability during wintering. Moreover, the chloroplast genome of E. japonicus Beihaidao is a typical double-linked ring tetrad structure, which is similar to that of the other four Euonymus species, E. hamiltonianus, E. phellomanus, E. schensianus, and E. szechuanensis, in terms of gene structure, gene species, gene number, and GC content. Compared to other Celastraceae species, the variation in the chloroplast genome sequence was lower, and the gene structure was more stable. The phylogenetic relationships of 37 species inferred that members of the Euonymus genus do not form a clade and that E. japonicus Beihaidao is closely related to E. japonicus and E. fortunei. A total of 11 functional positive selected genes were identified, which may have played an important role in the process of Celastraceae species adapting to environmental changes. Our study provides important genetic information to support further investigations into the phylogenetic development and adaptive evolution of Celastraceae species.

Long noncoding RNAs (lncRNAs) participate in a wide range of biological processes, but lncRNAs in plants remain largely unknown; in particular, we lack a systematic identification of plant lncRNAs involved in hormone responses. To explore the molecular mechanism of the response of poplar to salicylic acid (SA), the changes in protective enzymes, which are closely related to plant resistance induced by exogenous SA, were studied, and the expression of mRNA and lncRNA were determined by high-throughput RNA sequencing. The results showed that the activities of phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO), in the leaves of Populus × euramericana, were significantly increased by exogenous SA application. High-throughput RNA sequencing showed that 26,366 genes and 5690 lncRNAs were detected under the different treatment conditions: SA and H₂O application. Among these, 606 genes and 49 lncRNAs were differentially expressed. According to target prediction, lncRNAs and target genes involved in light response, stress response, plant disease resistance, and growth and development, were differentially expressed in SA-treated leaves. Interaction analysis showed that lncRNA–mRNA interactions, following exogenous SA, were involved in the response of poplar leaves to the external environment. Our study provides a comprehensive view of Populus × euramericana lncRNAs and offers insights into the potential functions and regulatory interactions of SA-responsive lncRNAs, thus forming the foundation for future functional analysis of SA-responsive lncRNAs in Populus × euramericana.