The sucrose non-fermentation-related protein kinase (SnRK) is a kind of Ser/Thr protein kinase, which plays a crucial role in plant stress response by phosphorylating the target protein to regulate the interconnection of various signaling pathways. However, little is known about the SnRK family in Eucalyptus grandis. Thirty-four putative SnRK sequences were identified in E. grandis and divided into three subgroups (SnRK1, SnRK2 and SnRK3) based on phylogenetic analysis and the type of domain. Chromosome localization showed that SnRK family members are unevenly distributed in the remaining 10 chromosomes, with the notable exception of chromosome 11. Gene structure analysis reveal that 10 of the 24 SnRK3 genes contained no introns. Moreover, conserved motif analyses showed that SnRK sequences belonged to the same subgroup that contained the same motif type of motif. The Ka/Ks ratio of 17 paralogues suggested that the EgrSnRK gene family underwent a purifying selection. The upstream region of EgrSnRK genes enriched with different type and numbers of cis-elements indicated that EgrSnRK genes are likely to play a role in the response to diverse stresses. Quantitative real-time PCR showed that the majority of the SnRK genes were induced by salt treatment. Genome-wide analyses and expression pattern analyses provided further understanding on the function of the SnRK family in the stress response to different environmental salt concentrations.

The valine glutamine (VQ) proteins are transcription cofactors involved in various aspects of plant biology, including growth, development, and stress resistance, making them an attractive target for genetic engineering aimed at enhancing plant resilience and productivity. However, comprehensive reports or systematic studies on VQ cofactors in Salix suchowensis remain lacking. In this study, we analyzed SsVQ genes using bioinformatics methods based on the Salix suchowensis genome database. Expression profiles were further investigated through qRT-PCR under six treatments: PEG, NaCl, 40 °C, ABA, SA, and MeJA. A total of 39 SsVQ genes were identified, with phylogenetic analysis classifying them into seven groups. Collinearity analysis suggested that SsVQ gene amplification primarily resulted from whole genome duplication (WGD) or segmental duplication events. Ka/Ks ratios indicated that willow VQ genes have undergone predominantly purifying selection. Gene structure analysis revealed that SsVQ genes are intronless. Multiple sequence alignment showed that SsVQ19 shares similarity with PtVQ27, containing a hydrophilic threonine (T) residue preceding the VQ amino acid residues. Furthermore, genes within each group exhibited conserved structures and VQ motifs. Promoter and expression analyses suggested the potential roles of SsVQ genes in regulating willow responses to environmental stresses and hormonal signals. Most SsVQ genes displayed differential expression at specific time points, with six members (SsVQ2, SsVQ9, SsVQ12, SsVQ23, SsVQ32, and SsVQ34) showing sustained high-amplitude expression profiles across treatments. Notably, SsVQ34 demonstrated pronounced transcriptional induction under PEG stress, with expression levels upregulated by 62.29-fold (1 h), 49.21-fold (6 h), 99.9-fold (12 h), and 201.50-fold (24 h). Certain SsVQ genes showed co-expression under abiotic/hormonal stresses, implying synergistic functions. Paralogous gene pairs exhibited stronger co-expression than non-paralogous pairs. This study provides novel insights into the structural and functional characteristics of the VQ gene family in Salix suchowensis, establishing a foundation for future research on the stress-resistance mechanisms of willow VQ genes.

Phenolic acids are known allelopathic compounds that may serve as the primary cause of continuous cropping obstacles in Coix lacryma-jobi L. (Coix). However, the concentrations, types, and specific stress responses of Coix to these phenolic acids still require further investigation. In this study, the cultivar ‘Wanyi 2′ was used to examine the effects of different phenolic acids and their concentrations on the growth of Coix. Four concentrations (0 mg/L, 10 mg/L, 100 mg/L, and 1000 mg/L) and four phenolic acid types (p-hydroxybenzoic acid, salicylic acid, cinnamic acid, and ferulic acid) were used to assess their influences on plant growth, leaf physiological parameters, and metabolic pathways under greenhouse conditions. In this greenhouse pot experiment, the effects of the four phenolic acids showed a similar tendency: a low concentration (10 mg/L) tended to promote the growth and root development of Coix seedlings, whereas high concentrations (100 and 1000 mg/L) generally showed inhibitory effects. Among these phenolic acids, ferulic acid exhibited the strongest inhibitory effect at the highest concentration (1000 mg/L), while salicylic acid showed the most pronounced growth-promoting effect at low concentrations (10 mg/L). In addition, high levels of phenolic acids markedly increased antioxidant enzyme activities and oxidative stress-related substances in Coix leaves, while reducing soluble sugar (SS) and soluble protein (SP) contents. Our data suggest that under phenolic acid stress, Coix leaves exhibited changes in the metabolism of phenolic acids (e.g., 4-methoxysalicylic acid, gallic acid) and amino acids (e.g., glutathione, proline), which may be associated with the adaptive response to allelochemical-induced stress. Overall, this study provides insights that may support strategies to optimize plant growth regulators and mitigate continuous cropping barriers in Coix.

HD-Zip (homeodomain-leucine zipper) transcription factors play a crucial role in plant growth, development, and stress response; however, the HD-Zip gene family of Coix lacryma-jobi L. has not been identified. In this study, a total of 40 HD-Zip gene family members were identified in the genome of Coix. According to phylogenetic analysis, the Coix HD-Zip gene was divided into four subfamilies (I–IV), of which the HD-Zip I subfamily can be further divided into five branches. Moreover, HD-Zip members of the same subfamily usually share similar gene structures and conserved motifs. The transcription factor binding site enrichment analysis showed that there are many motifs for binding with transcription factors such as ERF (Ethylene responsive factor), MYB (v-myb avian myeloblastosis viral oncogene homolog), and ARF (Auxin Response Factor) in the promoter region of the ClHDZ genes. The results of qPCR (Quantitative Polymerase Chain Reaction) and expression profile analysis showed that ClHD-Zip I genes showed different levels of expression under different stress treatments. Among them, ClHDZ4 was located in the nucleus, and its expression pattern was significantly upregulated under salt, drought, and high-temperature stress. In addition, ectopic expression of ClHDZ4 enhanced the growth of yeast strains under drought, salt, or high-temperature treatment. In summary, these results laid a foundation for further research on the resistance function of the Coix HD-Zip gene.