Integrated Transcriptomic and Metabolomic Analyses Reveal Early Concentration-Dependent Responses of Astragalus membranaceus var. mongholicus Seedlings to Imidacloprid
This work identifies key metabolic pathways and hub genes, offering candidate molecular markers for investigating pesticide stress adaptation in medicinal Astragalus and guiding standardized pesticide application in cultivation.
Abstract
Background: Imidacloprid, a widely used neonicotinoid insecticide, is routinely applied to control pests in Astragalus membranaceus var. mongholicus, a crucial medicinal herb producing Astragali Radix. However, the early short-term transcriptional and metabolic responses of its seedlings under imidacloprid gradient stress remain poorly characterized. Methods: In this study, 80-day seedlings were subjected to three foliar spray treatments: blank control (CK), the recommended imidacloprid concentration (2000-fold dilution, 475 mg·L−1), and an excessively high concentration (500-fold dilution, 1900 mg·L−1). Leaf samples were harvested 24 h post-treatment for untargeted ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS) metabolomics (6 biological replicates) and RNA-seq transcriptome sequencing (3 biological replicates). Results: The low- and high-dose treatments induced 1076 and 860 differential metabolites and 6818 and 7283 differentially expressed genes, respectively. Flavonoids, saponins, terpenoids, amino acid metabolites, and energy-related pathways were prominently affected. KEGG enrichment indicated activation of flavone/flavonol biosynthesis, phenylpropanoid metabolism, amino acid metabolism, MAPK signaling, cutin/suberin/wax biosynthesis, and ABC transporter pathways, whereas high-dose exposure was associated with stronger changes in genes related to DNA replication and cell wall remodeling. Integrated network analysis highlighted CHS, PAL, MYC2, KCS, and ABCG40 as candidate regulators linking stress signaling, secondary metabolism, and metabolite transport. Conclusions: Seedlings of A. membranaceus var. mongholicus exhibit dose-dependent acute responses to imidacloprid. Moderate pesticide exposure primarily activates defensive secondary metabolism, whereas excessive dosage triggers genome-wide transcriptional reprogramming. This work identifies key metabolic pathways and hub genes, offering candidate molecular markers for investigating pesticide stress adaptation in medicinal Astragalus and guiding standardized pesticide application in cultivation.
Gentiana lawrencei var. farreri (G. farreri) is an important endangered Tibetan medicinal plant. This study aimed to uncover temperature-mediated physiological and molecular mechanisms underlying growth and flowering of this endangered Tibetan medicinal herb, providing theoretical guidance for its standardized artificial cultivation. This study established three diurnal temperature treatments: 15/5 °C (S15), 20/10 °C (S20), and 25/15 °C (S25), and conducted integrated analyses of phenotypic, physiological, non-targeted metabolomic, and transcriptomic data. The results showed that S15 significantly promoted plant biomass accumulation and flowering, with a flowering rate of 45.83%, significantly higher than that of other treatments. S15 significantly reduced the levels of soluble sugar, soluble protein, fructose, and starch, while increasing CAT activity to enhance antioxidant capacity; endogenous hormones showed elevated gibberellin (GA) and decreased indole-3-acetic acid (IAA), establishing a hormonal balance favorable for flowering. Integrated metabolomic and transcriptomic analysis revealed that the flavonoid biosynthesis pathway (ko00941) is the core pathway responsive to temperature; S15 induces an increase in the contents of flavonoid metabolites including naringenin, delphinidin, petunidin, and peonidin, and simultaneously upregulates the expression of key genes including the PAL-encoding gene Cluster-62424.2, the 4CL-encoding gene Cluster-45063.0, and the CHS-encoding gene Cluster-44799.3 involved in flavonoid biosynthesis under this condition. S15 reduces the content of osmotic adjustment substances, increases GA content in plant branches, and enhances antioxidant capacity, which synergistically promotes the growth and flowering of G. farreri. Additionally, S15 mediates the accumulation of flavonoid compounds by regulating key genes involved in flavonoid biosynthesis, thereby elevating the accumulation of bioactive constituents isoorientin and isoscoparin-2″-O-β-D-glucopyranoside. This study can provide crucial theoretical support for the optimal temperature regulation and control in the artificial cultivation of G. farreri.
Lame Zeren, Zhuoma Deqing, Yue Xu et al.· Frontiers in Plant Science· 0 citations
These findings collectively support flavanone 3-hydroxylase (F3H) as a candidate regulatory node governing organ-specific flavonoid partitioning in Rhododendron yedoense var.
Leaf rust severely limits the yield and quality of Zanthoxylum armatum (Z. armatum). This study compared a rust-susceptible line (S-YF) and a naturally bud-sport-derived resistant line (R-YF) originating from the same mother plant, using physiological assays, widely targeted metabolomics, and transcriptomics to reveal the underlying resistance mechanisms. The total flavonoids and lignin were significantly higher in R-YF. A total of 298 differentially accumulated metabolites (DAMs) were identified, with enrichment of flavonoids and other defense-related secondary metabolites in R-YF. These compounds were primarily associated with the phenylpropanoid and flavonoid biosynthetic pathways. High-performance liquid chromatography (HPLC) confirmed elevated vitexin, rutin, and hydroxy-β-sanshool accumulation in R-YF, while transcriptome profiling revealed 1117 differentially expressed genes (DEGs). R-YF showed activated pathways associated with phenylpropanoid–flavonoid biosynthesis and stress signaling, which upregulated the structural genes involved in flavonoid production and the key BAHD acyltransferase gene responsible for hydroxy-β-sanshool synthesis. The AP2/ERF transcription factor family was identified as central to this process, revealing 284 ZaAP2/ERF members that demonstrated clear phylogenetic relationships, conserved domains, nuclear localization, tandem duplication expansion, and promoter enrichment for stress and secondary metabolism-related cis-elements. RT-qPCR was used to validate the expression patterns, indicating that ZaAP2/ERF positively regulated rust resistance. Overall, R-YF may reconfigure transcriptional and metabolic networks through ZaAP2/ERF to enhance the flavonoid and hydroxy-β-sanshool pathways. This resulted in the effective accumulation of defense metabolites, representing a potential key mechanism for resistance. This study provides a basis for the dissection of molecular mechanisms, resistance gene mining, and molecular breeding in Z. armatum.
Han-Lu Hu, Cheng-Jie Shu, Xiao-Xia Sun et al.· Biology· 0 citations
It is suggested that the reprogramming of amino acid and nitrogen metabolism may participate in the treatment response and could serve as a candidate response pathway for future development of plant-derived insecticides against L. trifolii.
Findings provide insights into the potential multifaceted insecticidal action of benzothiazole in T. castaneum at the transcriptomic level and support its further development as a target-specific grain fumigant.
Kai-Di Cui, Xue-Ran Hu, Weifeng Cheng et al.· Pest Management Science· 0 citations
Results suggest that the stronger resistance to P. nicotianae by X7 is associated with rapid coordination of defense-related transcription, phenylpropanoid and flavonoid metabolism, hormone signaling, and suppression of photosynthesis and primary metabolism.
Guo Li, Chang-Jiang Zhang, Bei Yu et al.· Plant physiology and biochem...· 0 citations
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