In Camellia sinensis 'Aijiao Oolong', from the bud stage to the full-bloom stage, amino acids (especially theanine) significantly increased, whereas catechins and alkaloids decreased. Transcriptomic analysis revealed extensive developmental-stage-associated changes in 8 hormone-related signaling pathways, among which auxin signaling contained the largest number of DEGs. As reproductive, non-leaf organs of tea plants, tea flowers are rich in bioactive substances and possess great potential for high-value utilization. However, the mechanisms underlying flower development in the distinctive oolong tea cultivar Aijiao Oolong remain unclear. This study integrated targeted metabolomics and transcriptomics to analyze tea flowers at the bud and full-bloom stages. The sum of the 25 quantified free amino acids was 35.26 mg/g at the full-bloom stage, 1.66-fold that at the bud stage (21.28 mg/g). 18 quantified free amino acids showed significantly higher contents at the full-bloom stage, whereas aspartic acid showed a significantly lower content and six amino acids showed no significant difference. Theanine was the most abundant quantified free amino acid and increased from 8.84 to 13.98 mg/g. In contrast, the sums of the nine quantified catechins and three quantified purine alkaloids were lower at the full-bloom stage. Transcriptomic analysis identified 122 DEGs associated with 8 hormone-related signaling pathways. Among them, auxin signaling contained the largest number of DEGs and exhibited extensive transcriptional changes, suggesting that auxin-related signaling may be prominently involved in flower development. Integrated pathway analysis indicated that changes in nitrogen and amino-acid metabolism were associated with higher amino-acid contents, whereas changes in flavonoid and purine metabolism were associated with lower catechin and caffeine contents. These findings provide an integrated view of developmental-stage-associated metabolic and transcriptional changes in Aijiao Oolong tea flowers, providing insights into flower development and the potential high-value utilization of tea flowers.
The macaw palm (Acrocomia spp.) stands out as a promising species for the sustainable production of vegetable oil due to its wide adaptability and potential use in multiple production chains. This study evaluated 11 genotypes, including parental genotypes and F₁ hybrids, for fruit biometric traits and mesocarp oil content, aiming to identify individuals with greater potential for genetic improvement programs. Analyses were carried out in plant material belonging to the Active Germplasm Bank of Macaw palm of the Federal University of Viçosa. The variables were subjected to analyses of variance, phenotypic correlation, and genetic diversity based on Mahalanobis generalized distance and the Tocher and UPGMA clustering methods. A broad phenotypic and genetic variability was observed among genotypes. Individual A4 exhibited larger fruits with higher mass and a greater pulp yield index, whereas the parent 47 − 1 showed the highest mesocarp oil content (55.31
Global warming intensifies high-temperature stress, threatening the growth and heartwood formation of Santalum album L. To elucidate the molecular basis of the heat-stress response, we conducted transcriptomic and metabolomic analyses on sandalwood seedlings under heat stress. Results showed: (1) Transcriptome identified 2,501 and 866 differentially expressed genes (DEGs) in TR0 vs. TR1 and TR1 vs. TR2 respectively (TD stands for metabolome samples, TR stands for transcriptome samples; suffix numbers correspond to sampling time points: 0 = day 0 before stress, 1 = day 1 of stress, 2 = day 3 of stress), mainly involving pathways such as plant hormone signal transduction, endoplasmic reticulum protein processing, heat shock protein regulation, and reactive oxygen species (ROS) clearance; (2) 26,244 and 20,451 metabolic ion features were detected in the positive and negative ion modes (PI and NI), respectively. The number of differentially expressed metabolites (DEMs) increased with stress time, and key metabolites of phenylpropanoid pathway such as 4-Hydroxycinnamic acid changed significantly. (3) Integrated analysis indicated that phenylpropanoid biosynthesis pathway was core response pathway, with high expression of key enzyme genes (PAL, C4H, 4CL). Expression level of the CHS gene (SA08G01315) in the flavonoid branch was significantly induced, which may be involved in antioxidant defense under heat stress. In the lignin branch, HCT transcript levels increased while COMT decreased sharply—a shift potentially linked to the wilting phenotype on day 3. Crucial enzyme genes like CAD were also highly expressed, indicating enhanced lignin monomer biosynthesis potential. Transcription factors (TFs) including ERF and MYB participated in pathway regulation. This study identified candidate key pathways and genes associated with the heat stress response in sandalwood, providing scientific evidence for subsequent variety improvement, domestication, and mechanistic research on plant thermal adaptation.
Seven LkMIR396 precursor genes were identified in Larix kaempferi, and their developmental and hormone responsive expression patterns suggest potential involvement in somatic embryogenesis. MicroRNA396 (miR396) is a highly conserved small RNA that regulates plant growth and development by targeting GROWTH-REGULATING FACTOR (GRF) transcription factors. However, its functions in gymnosperms, particularly conifers, remain poorly understood. In this study, seven precursor genes of LkMIR396 were cloned and identified from Larix kaempferi, all of which form typical stem-loop structures and produce three distinct mature Lk-miR396 sequences. The LkMIR396 family exhibited rapid and differential responses to exogenous hormones in embryogenic cell masses, with jasmonic acid (JA) strongly suppressing expression of all members. Heterologous overexpression of Lkpre-MIR396b1 in Arabidopsis thaliana significantly reduced rosette leaf area, length, and width accompanied by reduced expression of several predicted AtGRF targets. This effect may be achieved by attenuation of cytokinin (CK) signaling and activation of the JA pathway, as revealed by integrated transcriptome and metabolome analysis. During somatic embryogenesis, LkMIR396 family members showed low expression levels at early stages and a significant increase during the cotyledon stage (21–28 days), suggesting a potential association in cotyledon development. These results support the functional compatibility and possible conservation of the miR396–GRF regulatory module across seed plants. However, the direct functions of LkMIR396 during L. kaempferi somatic embryogenesis remain to be experimentally validated. This study provides a foundation for understanding the evolution and potential developmental functions of the miR396 family in conifers and identifies candidate regulatory relationships for future functional investigation.
Resin extraction modifies xylogenesis dynamics while maintaining annual xylem increment, inducing anatomical adjustments associated with hydraulically safer xylem traits. Traditional tapping appeared to provide the most balanced trade-off between resin yield and wood formation. Resin extraction in maritime pine (Pinus pinaster Aiton) constitutes a metabolic sink that theoretically competes with cambial activity for carbon resources. To mitigate potential wood formation impacts, shortened tapping periods are often proposed, yet their physiological effect remains unclear. This study investigated the impact of Traditional (March–October) versus Shortened (June–October) resin tapping regimes on annual radial increment, xylogenesis kinetics, and wood anatomy in a stand in central Portugal. Resin extraction did not reduce annual tree-ring width or total tracheid production compared to untapped Control trees. However, tapping altered the phenology of wood formation. While Control trees exhibited a typical Mediterranean bimodal growth pattern with a summer quiescence, tapped trees shifted to a continuous, prolonged period of wood formation, maintaining cambial activity into summer and late autumn to compensate for lower daily cell production rates. Anatomically, resin-tapped trees developed xylem characterized by narrower lumens and thicker cell walls, suggesting possible structural adjustments in xylem formation that may be associated with hydraulic function. The Shortened regime was not associated with clear advantages in resin production or wood formation dynamics. The Traditional method appeared to be the best silviculture option for co-production under the conditions evaluated in this study, with P. pinaster demonstrating sufficient plasticity to sustain both secondary growth and defense through temporal and anatomical adjustments.
