Dayun Zhou

Tea plants are frequently threatened by insect pests, resulting in substantial yield and quality losses. Methyl jasmonate (MeJA) is a key defense signaling molecule in plants; however, its integrated effects on tea plant growth, resistance, and quality-related traits remain poorly understood. In this study, field experiments were conducted to evaluate the effects of exogenous MeJA at different concentration (0.02–20 mM) on growth traits, quality components, and resistance to the tea green leafhopper and tea orange gall mite in Camellia sinensis ‘Zhongcha 108’, and transcriptome analysis was further integrated to elucidate the underlying molecular mechanisms. The results showed that appropriate MeJA concentrations (0.2–2 mM) significantly optimized bud morphology, characterized by shortened internodes, thicker stems, and reduced leaf insertion angles. Importantly, these treatments did not significantly alter the measured quality-related biochemical components, such as free amino acids and soluble sugars, within the evaluated time frame. Collectively, this study provides the first field-based evidence defining an effective MeJA concentration window that balances pest resistance induction, growth modulation, and processing suitability for flat-type green tea, offering practical guidance for the rational application of MeJA in tea plantation management.

This study aimed to evaluate the impact of Spinetoram (SPI) on the midgut of Apis cerana cerana Fabricius pupae, emphasizing detoxifying enzyme activity, gene expression, and morphological alterations. Pupae were subjected to SPI at LC₂₀ and LC₅₀ concentrations, and the midgut was evaluated using morphological assessment, detoxifying enzyme assays, and transcriptome analysis utilizing gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Transcriptome analysis revealed 32 differentially expressed genes (DEGs) that were common to both the LC₂₀ vs. control (CK) and LC₅₀ vs. CK comparisons, along with 24 DEGs unique to the LC₂₀ vs. CK comparison and 76 DEGs unique to the LC₅₀ vs. CK comparison. KEGG pathway analysis indicated the substantial enrichment of pathways associated with drug metabolism, xenobiotic metabolism, and amino acid metabolism, implying disruptions in detoxification mechanisms and broader metabolic imbalances resulting from SPI exposure. Morphological analysis showed a normal midgut structure in the control group, while significant damage was observed in the LC₂₀ group, and severe degeneration was observed in the LC₅₀ group. Detoxification enzyme assays revealed that the activities of cytochrome P450, glutathione S-transferase, and carboxylesterase significantly increased at LC₂₀ (p < 0.05), indicating an initial induction of detoxification responses; however, they declined at LC₅₀, suggesting enzyme inhibition or midgut damage. The activity of acetylcholinesterase markedly diminished at both LC₂₀ and LC₅₀ (p < 0.05), with a more substantial decline observed at LC₅₀, suggesting possible neurotoxicity. These findings indicate that SPI exposure causes substantial alterations in midgut morphology, detoxifying enzyme activity, and gene expression in Apis cerana cerana Fabricius pupae, underscoring the insecticide’s detrimental impact on honey bee health.