Background: Vernonia galamensis native to Africa is an annual oleaginous plant of Asteraceae family. As a newly established industrial oil crop, this plant produces high level (> 70%) of vernolic acid (cis-12-epoxyoctadeca-cis-9-enoic acid), which is an unusual epoxy fatty acid (EFA) with multiple industrial applications. Here, transcriptome analysis and fatty acid profiling from developing V. galamensis seeds were integrated to uncover the critical metabolic pathways responsible for high EFA accumulation, aiming to identify the target genes that could be used in the biotechnological production of high-value oils. Results: Based on oil accumulation dynamics of V. galamensis seeds, we harvested seed samples from three stages (17, 38, and 45 days after pollination, DAP) representing the initial, fast and final EFA accumulation phases, and one mixed sample from different tissues for RNA-sequencing, with three biological replicates for each sample. Using Illumina platform, we have generated a total of 265 million raw cDNA reads. After filtering process, de novo assembly of clean reads yielded 67,114 unigenes with an N50 length of 1316 nt. Functional annotation resulted in the identification of almost all genes involved in diverse lipid-metabolic pathways, including the novel fatty acid desaturase/epoxygenase, diacylglycerol acyltransferases, and phospholipid:diacylglycerol acyltransferases. Expression profiling revealed that various genes associated with acyl editing, fatty acid β-oxidation, triacylglycerol assembly and oil-body formation had greater expression levels at middle developmental stage (38 DAP), which were consistent with the fast accumulation of EFA in V. galamensis developing seed, these genes were detected to play fundamental roles in EFA production. In addition, we isolated some transcription factors (such as WRI1, FUS3 and ABI4), which putatively regulated the production of V. galamensis seed oils. The transient expression of the selected genes resulted in a synergistic increase of EFA-enriched TAG accumulation in tobacco leaves. Transcriptome data were further confirmed by quantitative real-time PCR for twelve key genes in EFA biosynthesis. Finally, a comprehensive network for high EFA accumulation in V. galamensis seed was established. Conclusions: Our findings provide new insights into molecular mechanisms underlying the natural epoxy oil production in V. galamensis. A set of genes identified here could be used as the targets to develop other oilseeds highly accumulating valued epoxy oils for commercial production.

Calcium-dependent protein kinases (CDPKs) serve as calcium ion sensors and play crucial roles in all aspects of plant life cycle. While CDPK gene family has been extensively studied in various plants, there is limited information available for CDPK members in oat, an important cereal crop worldwide. Totally, 60 AsCDPK genes were identified in oat genome and were classified into four subfamilies based on their phylogenetic relationship. The members within each subfamily shared similar gene structure and conserved motifs. Collinearity analysis revealed that AsCDPK gene amplification was attributed to segmental duplication events and underwent strong purifying selection. AsCDPK promoters were predicted to contain cis-acting elements associated with hormones, biotic and abiotic stresses. AsCDPK gene expressions were induced by different salt stresses, exhibiting stress-specific under different salt treatments. Moreover, overexpression of AsCDPK26 gene enhanced salt resistance in C. reinhardtii, a single-cell photoautotrophic model plants. Further analysis revealed a significant correlation between AsCDPK26 and Na⁺/H⁺ antiporter 1 (p<0.05), suggesting that AsCDPK26 may interact with ion transporter to modulate salt resistance. These results not only provide valuable insights into AsCDPK genes in response to different salt stresses, but also lay the foundation to mine novel candidates for improving salt tolerance in oat and other crops.

Oat (Avena sativa), an economically important cereal crop globally, is highly vulnerable to high-temperature stress, challenging its geographic distribution and grain production. However, the mechanisms underlying oat’s response to heat stress remain pooly understood. A time-course transcriptome revealed significant enrichment in lipid metabolism pathways during heat stress, which was corroborated by metabolomic findings. Integrated co-expression network analysis and KEGG enrichment further underscored the critical role of lipid metabolism in oat’s adaptive response to heat stress. Comprehensive lipidomic profiling of heat-stressed oat seedlings demonstrated a substantial increase in the proportion of neutral lipids, suggesting an evolutionarily conserved protective strategy. Synergistic transcriptional responses indicated that heat-induced triacylglycerol (TAG) accumulation primarily originated from extensive membrane lipid turnover rather than de novo fatty acid (FA) synthesis, with the Kennedy pathway serving as the dominant route for TAG production. Enhanced phospholipid hydrolysis, acyl editing, and endoplasmic reticulum-localized FA desaturation collectively contributed to TAG enrichment in polyunsaturated FAs. Additionally, elevated levels of phosphatidylglycerol (PG) and phosphatidylinositol (PI) in oat may confer adaptive benefits under heat stress. This study demonstrates that lipid metabolism critically regulates heat stress response in oat. The findings provide valuable target genes for genetic improvement in enhancing oat thermotolerance.

Lead (Pb) poisoning is a major public health concern of environmental origin in the world. It is essential to develop effective ways such as utilizing natural products as therapeutic agents for prevention and therapy of Pb‐induced diseases. This study explores the effects and underlying mechanisms of astaxanthin (ATX), a natural compound with potent antioxidant properties, in alleviating Pb‐induced toxicity in model mice. Supplementation with ATX significantly ameliorated lead‐induced physiological and biochemical disruptions, including weight loss, hepatic and renal damage, and metabolic imbalances. Metabolomic and transcriptomic analyses revealed that ATX played a positive role in improving redox homeostasis, regulating lipid, amino acid, and nucleotide metabolism, and activating critical pathways such as Nrf2/ARE, PPAR, and S1P, thereby enhancing the antioxidative, anti‐inflammatory, and detoxification capacities of the mice. ATX supplementation also modulated mouse gut microbiota by promoting beneficial bacterial populations, suppressing harmful strains, and increasing short‐chain fatty acid production, thereby effectively restoring gut‐liver axis balance. These findings demonstrate that ATX possesses comprehensive activities against lead toxicity via multi‐dimensional regulatory mechanisms, highlighting ATX as a promising therapeutic agent for heavy metal poisoning. Further research is warranted to validate the clinical applications of ATX and evaluate its long‐term safety.