Glutathione S-transferases (GSTs) play a crucial role in responding to abiotic stress and are an important target for research on plant stress tolerance mechanisms. Populus euphratica is a promising candidate species for investigating the abiotic tolerance mechanisms in woody plants. In our previous study, PeGSTU58 was identified as being associated with seed salinity tolerance. In the present study, PeGSTU58 was cloned from P. euphratica and functionally characterized. PeGSTU58 encodes a Tau class GST and is located in both the cytoplasm and nucleus. Transgenic Arabidopsis overexpressing PeGSTU58 displayed enhanced tolerance to salt and drought stress. Under salt and drought stress, the transgenic plants exhibited significantly higher activities of antioxidant enzymes, including SOD, POD, CAT, and GST, compared to the wild-type (WT) plants. Additionally, the expression levels of several stress-responsive genes, including DREB2A, COR47, RD22, CYP8D11, and SOD1 were upregulated in PeGSTU58 overexpression lines compared to those in WT Arabidopsis under salt and drought stress conditions. Furthermore, yeast one-hybrid assays and luciferase analysis showed that PebHLH35 can directly bind to the promoter region of PeGSTU58 and activate its expression. These results indicated that PeGSTU58 was involved in salt and drought stress tolerances by maintaining ROS homeostasis, and its expression was positively regulated by PebHLH35.

Late embryonic developmental abundant (LEA) genes play a crucial role in the response to abiotic stress and are important target genes for research on plant stress tolerance mechanisms. Acer truncatum Bunge is a promising candidate tree species for investigating the tolerance mechanism of woody plants against abiotic stress. In our previous study, AtruLEA1 was identified as being associated with seed drought tolerance. In this study, LEA1 was cloned from A. truncatum Bunge and functionally characterized. AtruLEA1 encodes an LEA protein and is located in the nucleus. Phylogenetic tree analysis revealed a recent affinity of the AtruLEA1 protein to AT3G15760.1. Overexpression of AtruLEA1 resulted in enhanced tolerance of Arabidopsis thaliana to drought and salt stress and heightened the ABA sensitivity. Compared to wild-type (WT) plants, plants with overexpressed AtruLEA1 exhibited increased activities of antioxidant enzymes under drought stress. Meanwhile, the ROS level of transgenic Arabidopsis was significantly less than that of the WT. Additionally, the stoma density and stoma openness of AtruLEA1 Arabidopsis were higher compared to those in the WT Arabidopsis under salt and drought stress conditions, which ensures that the biomass and relative water content of transgenic Arabidopsis are significantly better than those of the WT. These results indicated that AtruLEA1 was involved in salt and drought stress tolerances by maintaining ROS homeostasis, and its expression was positively regulated by abiotic stress. These results indicate a positive role of AtruLEA1 in drought and salt stress and provide theoretical evidence in the direction of cultivating resistant plants.

Drought stress is one of the major environmental factors severely restricting plant development and productivity. Acer truncatum B, which is an economically important tree species, is highly tolerant to drought conditions, but the underlying molecular regulatory mechanisms remain relatively unknown. In this study, A. truncatum seedlings underwent a drought treatment (water withheld for 0, 3, 7, and 12 days), after which they were re-watered for 5 days. Physiological indices were measured and a transcriptome sequencing analysis was performed to reveal drought response-related regulatory mechanisms. In comparison to the control, the drought treatment caused a significant increase in antioxidant enzyme activities, with levels rising up to seven times, and relative electrical conductivity from 14.5% to 78.4%, but the relative water content decreased from 88.3% to 23.4%; these indices recovered somewhat after the 5-day re-watering period. The RNA sequencing analysis identified 9126 differentially expressed genes (DEGs), which were primarily involved with abscisic acid responses, and mitogen-activated protein kinase signaling. These DEGs included 483 (5.29%) transcription factor genes from 53 families, including ERF, MYB, and NAC. A co-expression network analysis was conducted and three important modules were analyzed to identify hub genes, one of which (AtruNAC36) was examined to clarify its function. The AtruNAC36 protein was localized to the nucleus and had a C-terminal transactivation domain. Moreover, it bounded specifically to the NACRS element. The overexpression of AtruNAC36 in Arabidopsis thaliana resulted in increased drought tolerance by enhancing antioxidant enzyme activities. These findings provide important insights into the transcriptional regulation mediating the A. truncatum response to drought. Furthermore, AtruNAC36 may be relevant for breeding forest trees resistant to drought stress.

Multiplier onion (Allium cepa var. aggregatum) is an economically important Allium crop that serves dual purposes as both a culinary ingredient and medicinal resource. Despite its widespread utilization, systematic characterization of its nutrient metabolism components remains limited, which has constrained the development of high-value cultivars with optimized nutritional profiles. In this study, we conducted a comprehensive metabolomic profiling of bulbs from five genetically distinct accessions using a widely targeted metabolomic method based on ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS). The analysis identified 659 metabolites, including lipids, flavonoids, phenolic acids, amino acids, saccharides and alcohols, organic acids, alkaloids, nucleotides and derivatives, vitamins, etc. Notably, the bulbs exhibited a high abundance of flavonoids (e.g., quercetin, kaempferol, naringenin, isorhamnetin) and eight essential amino acids (valine, threonine, leucine, isoleucine, lysine, methionine, histidine, and tryptophan). Comparative analysis revealed that 366 differentially accumulated metabolites were identified among these 5 accessions, many of which were significantly enriched in pathways related to flavonoid biosynthesis, as well as amino acid biosynthesis and metabolism. Transcriptome analysis indicated that differentially expressed genes (DEGs) across the five accessions were significantly enriched flavonoid biosynthesis, and various amino acid biosynthesis and metabolism processes, such as “tyrosine metabolism”, “phenylalanine, tyrosine, and tryptophan biosynthesis”, “cysteine and methionine metabolism” and “arginine and proline metabolism”, being consistent with the substantial variations observed in flavonoids, amino acids, and their derivatives in the metabolome analysis. Correlation and network analysis identified several crucial candidate regulatory genes for the biosynthesis and metabolism of lipids, flavonoids, phenolic acids, and amino acids. These findings provide a comprehensive metabolic atlas of multiplier onion, reveal key genetic regulators of nutritional quality, and establish a scientific foundation for nutraceutical development and cultivar improvement strategies.

Salix psammophila, C. Wang & Chang Y. Yang, a desert-adapted shrub, is recognized for its exceptional drought tolerance and plays a vital role in ecosystem maintenance. However, research on S. psammophila has been limited due to the lack of an efficient and reliable genetic transformation method, including gene functional studies. The Agrobacterium-mediated transient overexpression assay is a rapid and powerful tool for analyzing gene function in plant vivo. In this study, tissue culture seedlings of S. psammophila were utilized as the recipient materials, and the plant expression vector pCAMBIA1301, containing the GUS reporter gene, was transferred into the seedlings via an Agrobacterium-mediated method. To enhance the efficiency of the system, the effects of secondary culture time, Agrobacterium concentration, infection time, and co-culture duration on the transient transformation efficiency of S. psammophila were explored. The optimal combination for the instantaneous transformation of S. psammophila tissue culture seedlings mediated by Agrobacterium was determined as follows: a secondary culture time of 30 d, a value of OD₆₀₀ of 0.8, an infection time of 3 h, and a co-culture duration of 48 h. Subsequently, the effectiveness of the transformation system was validated using the S. psammophila drought response gene SpPP2C80. To further confirm the accuracy of the system, SpPP2C80-overexpressing Arabidopsis was constructed and drought resistance analysis was performed. The results were consistent with the transient overexpression of SpPP2C80 in S. psammophila tissue culture seedlings, indicating that this system can be effectively employed for studying gene function in S. psammophila. These findings provide essential information for investigating gene function in non-model plants and pave the way for advancements in molecular biology research in S. psammophila.

Multiplier onion (Allium cepa L. var. aggregatum) is an important bulbous vegetable widely utilized for culinary, condimental, and medicinal purposes. However, limited research on its genetic diversity and phenotypic variation has hindered the development and utilization of superior cultivars. In this study, we conducted full-length transcriptome profiling to obtain unique transcripts and develop large-scale simple sequence repeat (SSR) markers. Subsequently, we employed integrative analysis to characterize the genetic and phenotypic variation of 263 multiplier onion accessions in China. Full-length transcriptome sequencing utilizing PacBio technology generated 61,108 high-quality non-redundant transcripts with an average length of 1816 bp, from which we developed 4124 SSR markers encompassing 100 motif types. Population structure, principal component analysis, and neighbor-joining phylogenetic analysis classified the 263 multiplier onion accessions into two distinct subpopulations: Pop1, consisting of 236 accessions primarily from Heilongjiang Province, and Pop2, comprising 27 accessions mostly from Shaanxi Province. Phenotypic evaluation demonstrated significant variation in bulb traits, with single bulb weight (SBW) exhibiting the highest variability (0.75–29.94 g; CV = 70.10%), followed by total bulb weight per plant (BW) (5.00–168.83 g; CV = 58.34%), indicating considerable potential for breeding high-yield varieties. Correlation analysis indicated that the SBW and BW had significantly positive correlations with multiple traits, including bulb height, bulb transverse diameter, diameter of basal plate of bulb, diameter of bulb neck, and number of cloves per bulb. Our findings provide a valuable genetic and phenotypic resource for the conservation and utilization of multiplier onion germplasms.