Tetraploid plants often have altered rates of vegetative growth relative to their diploid progenitors. However, the molecular basis for altered growth rates remains a mystery. This study reports microRNA (miRNA) and gene expression differences in Populus tetraploids and counterpart diploids using RNA and miRNA sequencing. The results showed that there was no significant difference between young leaves in the expression of vegetative growth-related miRNAs. However, as leaves aged, the expression of auxin- and gibberellin-related miRNAs was significantly upregulated, while the expression of senescence-related miRNAs was significantly downregulated. The dose effect enhanced the negative regulation of the target genes with ARFs, GA20ox, GA3ox, and GAMYB being downregulated, and TCP and NAC being upregulated. As a result, the chloroplast degradation of tetraploid leaves was accelerated, the photosynthetic rate was decreased, and the synthesis and decomposition ability of carbohydrate was decreased.

Fagopylum tatarium (L.) Gaertn (buckwheat) can be used both as medicine and food and is also an important food crop in barren areas and has great economic value. Exploring the molecular mechanisms of the response to cadmium (Cd) stress can provide the theoretical reference for improving the buckwheat yield and quality. In this study, perennial tartary buckwheat DK19 was used as the experimental material, its key metabolic pathways in the response to Cd stress were identified and verified through transcriptomic and metabolomic data analysis. In this investigation, 1798 metabolites were identified through non-targeted metabolomic analysis containing 1091 up-regulated and 984down-regulated metabolites after treatment. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of differential metabolites was significantly enriched in galactose metabolism, glycerol metabolism, phenylpropane biosynthesis, glutathione metabolism, starch and sucrose metabolism. Linkage analysis detected 11 differentially expressed genes (DEGs) in the galactose metabolism pathway, 8 candidate DEGs in the lipid metabolism pathway, and 20 candidate DEGs in the glutathione metabolism pathway. The results of our study provided useful clues for genetically improving the resistance to cadmium by analyzing the molecular mechanism of cadmium tolerance in buckwheat.

Cereal crops are important staple foods, and their defense metabolites hold significant research importance. In this study, we employed LC-MS-based untargeted and widely-targeted metabolomics to profile the leaf metabolome of nine cereal species, including rice, wheat, maize, barley, sorghum, common oat, foxtail millet, broomcorn millet, and adlay. A total of 9869 features were detected, among them, 1131 were annotated, encompassing 18 classes such as flavonoids, lipids, and alkaloids. Results revealed that 531 metabolites were detected in all species, while each cereal crop possessed 4 to 12 unique metabolites. Focusing on defense metabolites, we identified eight benzoxazinoids uniquely present in maize, wheat, and adlay. Hierarchical clustering based on metabolite abundance divided all metabolites into nine clusters, and subsequent pathway enrichment analysis revealed that the stress-related flavonoid biosynthesis pathway was enriched in multiple clusters. Further analysis showed that four downstream compounds of HBOA (2-hydroxy-1,4-benzoxazin-3-one) in the benzoxazinoid biosynthesis pathway were enriched in maize. Wheat uniquely accumulated the 4′-methylated product of tricin, trimethoxytricetin, whereas adlay accumulated the tricin precursor tricetin in the flavonoid biosynthesis pathway. In summary, this study elucidates the metabolic diversity in defense metabolites among various cereal crops, providing valuable background information for the improvement of stress resistance in cereal crops.

Ehretia macrophylla fruit is a traditionally used but underutilized functional resource that is noted for its diverse phytochemical composition, which includes flavonoids and polyphenols. However, the systematic metabolic transformations that occur in the fruit during post-harvest storage—particularly those associated with its traditional processing into dark fruit tea—remain largely unknown, limiting efforts to optimize quality and processing strategies. In the study, to address this gap, we employed a widely targeted metabolomics approach based on ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) to dynamically profile the fruit metabolome across four storage stages (T0, T4, T8, T12). A total of 1101 metabolites were putatively annotated, and day 8 (T8) emerged as a potential pronounced metabolic inflection point. From T8 onward, 30–40% of metabolites showed differential accumulation, characterized by a gradual rise in nutrition-relevant lipids, amino acids, and vitamins. In contrast, key antioxidant-related metabolites, including phenolics and flavonoids, increased transiently before T8 but declined sharply thereafter. These coordinated shifts correlated with an increased representation of lipid- and alkaloid-related metabolic pathways, whereas flavonoid-associated features showed a relative decline. Collectively, these findings provide insights into the biochemical processes potentially associated with fruit blackening and the marked decline in antioxidant capacity during traditional processing. Our study provides the first metabolic blueprint connecting traditional processing practices with phased metabolic remodeling, offering a scientific foundation for quality assessment and the development of informed post-harvest strategies for processing E. macrophylla fruit.

α-Bisabolol is naturally occurring in many plants and has great potential in health products and pharmaceuticals. However, the current extraction method from natural plants is unsustainable and cannot fulfil the increasing requirement. This study aimed to develop a sustainable strategy to enhance the biosynthesis of α-bisabolol by metabolic engineering. Integration of ERG20 (encoding farnesyl diphosphate synthase) and tHMG1 (encoding truncated 3-hydroxy-3-methylglutaryl-CoA reductase) genes with a constitutive strong promoter into the yeast genome elevated α-bisabolol production from 20.21 mg/L to 98.30 mg/L, representing a 4.86-fold increase. Further optimization of the mevalonate pathway and amplification of ERG20, tHMG1, and OsTPS1 copy numbers enhanced α-bisabolol synthesis to 423.01 mg/L, achieving a 20.93-fold improvement relative to the baseline. This work establishes a reference strategy for high-yield α-bisabolol biosynthesis in engineered yeast.