Hempseed is a nutrient-rich natural resource, and high levels of hempseed oil accumulate within hemp seeds, consisting primarily of different triglycerides. Members of the diacylglycerol acyltransferase (DGAT) enzyme family play critical roles in catalyzing triacylglycerol biosynthesis in plants, often governing the rate-limiting step in this process. As such, this study was designed to characterize the Cannabis sativa DGAT (CsDGAT) gene family in detail. Genomic analyses of the C. sativa revealed 10 candidate DGAT genes that were classified into four families (DGAT1, DGAT2, DGAT3, WS/DGAT) based on the features of different isoforms. Members of the CsDGAT family were found to be associated with large numbers of cis-acting promoter elements, including plant response elements, plant hormone response elements, light response elements, and stress response elements, suggesting roles for these genes in key processes such as development, environmental adaptation, and abiotic stress responses. Profiling of these genes in various tissues and varieties revealed varying spatial patterns of CsDGAT expression dynamics and differences in expression among C. sativa varieties, suggesting that the members of this gene family likely play distinct functional regulatory functions CsDGAT genes were upregulated in response to cold stress, and significant differences in the mode of regulation were observed when comparing roots and leaves, indicating that CsDGAT genes may play positive roles as regulators of cold responses in hemp while also playing distinct roles in shaping the responses of different parts of hemp seedlings to cold exposure. These data provide a robust basis for further functional studies of this gene family, supporting future efforts to screen the significance of CsDGAT candidate genes to validate their functions to improve hempseed oil composition.

Background: As a major food crop, maize is highly susceptible to pathogenic bacteria, which greatly reduces its yield and quality. Metabolomics reveals physiological and biochemical changes in organisms and aids in analyzing metabolic changes caused by various factors. Methods: This study utilized metabolomics to examine maize’s metabolic changes after NCLB infestation, aiming to uncover related pathways and potential biomarkers. The metabolite measurements were performed during the maize silking stage. Results: PCA showed an obvious dispersion between the treated and untreated groups. OPLS-DA identified 1274 differential metabolites, with 242 being downregulated (mainly phenolics and esters) and 1032 upregulated (primarily organic acids, amino acids, sugars, and derivatives). KEGG annotation revealed 50 affected metabolic pathways, and the biosynthesis of secondary metab-olites and amino acids was significantly enriched. Conclusions: We hypothesized that metabolic pathways related to sugar metabolism, proline metabolism, and jasmonic acid synthesis are associated with NCLB susceptibility. These findings provide critical insights into the metabolic responses of maize to biotic stress, offering a theoretical basis for future research on plant resistance mechanisms.

Hemp possesses significant healthcare value due to its rich composition of unsaturated fatty acids and a distinctive golden ratio of linoleic acid to α-linolenic acid. As a promising special-oil crop, it holds substantial potential for development and utilization. However, the regulatory mechanisms underlying its lipid metabolic pathways remain poorly understood. In this study, the independently bred hemp seed variety Longdama No. 9 was used to construct a regulatory network of the fatty-acid and lipid metabolisms through integrative transcriptomic and lipidomic analysis. Transcriptomic profiling revealed differentially expressed genes (DEGs) involved in lipid biosynthesis across various tissues. In leaves, DEGs associated with glycerolipid synthesis were generally upregulated compared to in roots and seeds. In seeds, DEGs involved in fatty-acid synthesis and triacylglycerol (TAG) assembly were predominantly upregulated. Meanwhile, root tissues showed a higher abundance of upregulated DEGs related to phospholipid biosynthesis. Lipidomic analysis further highlighted tissue-specific lipid distributions. The galactolipid monogalactosyldiacylglycerol (MGDG) was most abundant in the leaves. While phosphatidylglycerol (PG) had the highest molar percentage in the seeds, most other major phospholipids were predominantly found in the roots. The prevalence of the C36:6 molecular species in the MGDG and digalactosyldiacylglycerol (DGDG) indicates that hemp is a typical 18:3 plant. The combined transcriptomic and lipidomic analysis revealed that tissue-specific transcriptional regulation contributes to the unique lipid profile of hemp. These findings provide valuable insights into the regulation of lipid metabolism in hemp and identify key genes involved in oil biosynthesis, which can lay a theoretical foundation for the development and utilization of hemp as a special-oil crop.