Transcriptomic Analysis Reveals the Molecular Mechanisms Underlying Heat-Induced Suppression of Polymethoxyflavone Accumulation in Citrus Leaves

NtWHY1 negatively regulates tobacco cold tolerance via interfering with flavonoid biosynthesis

Results indicate that NtWHY1 protein acts as a cold-induced negative regulator that attenuates cold tolerance in tobacco by repressing flavonoid biosynthesis and compromising antioxidant capacity, providing new insights into transcription factor-mediated modulation of secondary metabolism under abiotic stress.

Physiological and Transcriptomic Response of Exogenous Abscisic Acid and Brassinosteroid on Citrus Under Heat Stress

Heat stress severely hinders citrus yield and fruit quality. This study employed integrated physiological and transcriptomic analyses to investigate the effects of the exogenous application of abscisic acid (ABA) and brassinosteroid (BR) on heat stress responses in citrus. The results showed that the exogenous application of ABA and BR increased the contents of soluble sugar, proline, and ABA, and enhanced the activities of peroxidase and catalase under heat stress. Transcriptome trend analysis identified profiles 1, 6, and 7 as significantly enriched across exogenous ABA, BR, and control conditions. Profile 6 exhibited rapid upregulation followed by stabilization and showed a significantly higher gene count under both ABA and BR treatments than under the control. KEGG enrichment analysis revealed that genes in profile 6 were primarily enriched in amino sugar, nucleotide sugar, galactose, amino acids, 2-oxocarboxylic acid, glycerophospholipid, glucosinolate metabolism, MAPK signaling pathway, plant hormone signal transduction, protein processing in the endoplasmic reticulum, plant–pathogen interaction, and endocytosis. Furthermore, four genes encoding heat shock proteins (HSP), including HSP21A, HSP21B, HSP70-17, and HSP70A, were induced under heat stress and showed significant upregulation in response to exogenous ABA and BR treatments. In conclusion, these findings indicated that exogenous ABA and BR regulated ABA and osmoprotectant accumulation and antioxidant defense activation in response to heat stress.

Transcriptomic Insights into Heat-Induced Anthocyanin Suppression and Floral Color Fading in Chrysanthemum

High temperature (HT) is a crucial environmental factor influencing floral pigmentation and ornamental quality in chrysanthemum (Chrysanthemum morifolium) by modulating anthocyanin biosynthesis. In this study, comparative transcriptome profiling was performed in two F1 chrysanthemum lines (RO72 and RO99) under high-temperature stress to elucidate the molecular mechanisms behind heat-induced floral color fading. Analysis revealed extensive transcriptional reprogramming of genes associated with anthocyanin metabolism, hormonal signaling, and oxidative stress responses. While structural genes in the anthocyanin biosynthetic pathway (CHS, DFR, ANS, 3MAT and LDOX) were significantly downregulated, key glycosylation-related genes such as UFGT were upregulated, suggesting a compensatory mechanism that enhances pigment stabilization rather than de novo synthesis. This study identified a shift in the MYB–bHLH–WD40 regulatory complex, specifically the upregulation of transcriptional repressors (MYB62, MYB15) and downregulation of activators (MYB106, bHLH49), suggesting a suppressed anthocyanin accumulation. Simultaneously, genes associated with several signaling cascades such as ROS, ABA, and auxin–jasmonate signaling pathways were differentially expressed, suggesting that these alterations may contribute to the repression of pigment biosynthesis and color fading. Collectively, these results hypothesize that high temperature suppresses anthocyanin accumulation through a dual mechanism of transcriptional inhibition and hormonal modulation, while simultaneously promoting pigment stabilization via glycosylation. This study therefore provides fundamental insights into thermal regulation of floral pigmentation and identifies candidate genes and pathways potentially involved in heat-induced floral color fading in chrysanthemum.

Integrated phenotypic and transcriptomic analysis of herbicide stress response in hemp

Hemp ( Cannabis sativa L.) faces significant weed management challenges due to limited registered herbicides. This study evaluated tolerance of hemp to eight post-emergence herbicides and investigated the molecular mechanisms underlying tolerance to bispyribac-sodium through RNA sequencing. Greenhouse screening revealed that ACCase inhibitors caused minimal phytotoxicity, while Atrazine, Metribuzin, metsulfuron-methyl, and oxyfluorfen caused complete plant mortality. Bispyribac-sodium demonstrated partial tolerance with a GR 50 of 21.55 g a.i. ha − 1 , slightly above the field-recommended dose. Transcriptomic profiling revealed significant differential gene expression at 24 and 48 h after treatment, with early responses characterized by activation of MAPK signaling, secondary metabolite biosynthesis, and xenobiotic detoxification, while later responses shifted toward protein quality control and endoplasmic reticulum stress. A core set of 21 consistently upregulated detoxification genes, including tau-class glutathione S-transferases, UDP-glycosyltransferases, cytochrome P450s (CYP71, CYP72, CYP81, and CYP716 families), and an ABCB transporter, implicate a coordinated phase I-III detoxification framework in hemp’s herbicide tolerance. Weighted gene co-expression network analysis identified the yellow, purple, and pink modules as candidate co-expression networks underlying this response. These findings provide the first molecular reference for herbicide response in hemp and an evidence-based foundation for weed management strategies.

The free amino acid-rich biostimulant, Leafamine®, promotes cell division in tomato roots and alleviates heat stress effects

Heat stress-induced photosynthetic impairment and autophagy modulation in Paris polyphylla var. yunnanensis: A physiological and molecular Perspective

High temperature is one of the major environmental stressors that severely affects plant growth. Paris polyphylla var. yunnanensis, a traditional Chinese herbal medicine, is sensitive to high temperature. However, the underlying mechanisms of its response to high temperature remain unclear. In this study, we investigated the physiological and proteomic change of P. polyphylla var. yunnanensis under different treatments (25°C, 30°C, 35°C, 40°C). Our results showed that high temperature directly impaired photosynthesis and disrupted metabolism, evidenced by reduced chlorophyll and photosynthetic rate, as well as accumulated proline and increased conductivity. A total of 893 differentially expressed proteins (DEPs) were identified, with significant changes in the expression levels of enzymes associated with protein processing and synthesis. Additionally, the expression levels of key proteins involved in the circadian pathway and the glutathione pathway were also notably upregulated. Dynamic changes in the endocytosis and autophagy-related proteins ATG3 and ATG8C were also observed, suggesting that these processes may play a significant protective role under high-temperature stress. Overall, this study provides an important starting point for improving the heat tolerance of P.polyphylla var. yunnanensis through genetic engineering.