【目的】 筛选分析抗螨性不同的板栗(Castanea mollissima)叶片中的差异次生代谢物,为抗螨机理解析与高抗螨板栗品种选育提供参考。【方法】 以板栗品种‘燕兴’(‘Yanxing’)和‘丽抗’(‘Likang’)为材料,采用田间调查法进行抗螨性鉴定,确定‘燕兴’和‘丽抗’对针叶小爪螨的抗性等级;利用超高效液相色谱和串联质谱(UPLC-MS/MS)进行代谢组学检测,通过差异倍数(fold change)和VIP(variable importance in projection)值相结合的方法筛选差异代谢物,使用R软件ComplexHeatmap包和MetaboAnalystR包分别绘制聚类热图和OPLS-DA得分图;利用KEGG(Kyoto encyclopedia of genes and genomes)数据库对差异代谢物进行注释,并按通路类型分类。【结果】 ‘丽抗’和‘燕兴’对针叶小爪螨的抗性等级分别为1级(高抗)和7级(感);两品种共检测到704个次生代谢物,筛选出差异代谢物165个,有73个代谢物在 ‘丽抗’中的含量显著高于‘燕兴’,有92个差异代谢物在‘丽抗’中的含量比‘燕兴’低;差异代谢物种类包括酚酸(56个)、黄酮(60个)、木质素和香豆素(19个)、鞣质(4个)、生物碱(5个)、萜类(16个)和其他类(5个),差异代谢物中黄酮和酚酸类占比较高,分别为36%和34%;仅在‘丽抗’中检测到的代谢物有7个,分别是咖啡酰胆、6'-O-反式肉桂酰-8-表金吉苷酸、落叶松脂素-4'-O-葡萄糖苷、阿尔本酚B、地榆素H11、3-羟基-5甲基苯酚-O-葡萄糖苷和苜蓿素-7-O-葡萄糖醛酸苷等;仅存在于‘燕兴’中的代谢物有15个,包括4-甲基-5-噻唑乙醇、2,4-二羟基苯甲酸、异嗪皮啶、水杨苷、刺梨酸等。‘燕兴’和‘丽抗’中有33个差异代谢物被注释到12条通路上。【结论】 感螨品种‘燕兴’和高抗品种‘丽抗’次生代谢谱存在差异,可能与板栗抗螨性相关的次生代谢物有樱黄素、表没食子儿茶素、咖啡酸、阿魏酸、几种木质素以及4-甲基-5-噻唑乙醇;‘燕兴’和‘丽抗’的差异次生代谢物主要注释和富集在黄酮、黄酮醇生物合成及类黄酮生物合成通路。

【Objective】 The differential secondary metabolites in chestnut (Castanea mollissima) leaves with different mite resistance levels were screened to provide a reference for the analysis of the mite(Oligonychus ununguis) resistance mechanism and the breeding of highly mite-resistant chestnut varieties.【Method】 The chestnut varieties ‘Yanxing’ and ‘Likang’ were used to identify and determine the mite resistance levels to O. ununguis with the field investigation method. Metabolomics detection was performed using ultra-high-performance liquid chromatography and tandem mass spectrometry, and the differential metabolites were screened using a combination of fold change and the variable importance in projection value. The R software (ComplexHeatmap and MetaboAnalystR package) was used to draw the clustering heat map and orthogonal partial least squares-discriminant analysis score map. Identified metabolites were annotated using the Kyoto encyclopedia of genes and genomes (KEGG) database, and the annotation results were classified by pathway types.【Result】 The resistance levels of ‘Likang’ and ‘Yanxing’ to O. ununguis were high resistance and susceptible, respectively. A total of 704 secondary metabolites were detected, including 165 differential metabolites. The content of 73 metabolites in ‘Likang’ was significantly higher than in ‘Yanxing’, and the content of 92 metabolites was lower in ‘Likang’ than in ‘Yanxing’. The types of differential metabolites included 56 phenolic acids, 60 flavonoids, 19 lignins and coumarins, four tannins, five alkaloids, 16 terpenoids and five other types. Flavonoids and phenolic acids accounted for 36% and 34%, respectively. Metabolites present only in ‘Likang’ included caffeoylcholine-4-O-glucoside, 3-hydroxy-5-methylphenol-1-O-(6'-galloyl)glucoside, tricin-7-O-glucuronide, 6'-trans-cinnamoyl-8-epikingisidic acid, lariciresinol-4'-O-glucoside, albanol B and sanguiin H11. There were 15 metabolites present only in ‘Yanxing’, including 4-methyl-5-thiazoleethanol, 2,4-dihydroxybenzoic acid, isofraxidin, salicin and roxburic acid. Thirty-three differential metabolites in ‘Yanxing’ and ‘Likang’ were annotated to 12 metabolic pathways.【Conclusion】 The secondary metabolic profiles between the mite-susceptible variety ‘Yanxing’ and the highly resistant variety ‘Likang’ differed. Secondary metabolites that may be related to chestnut mite resistance were prunetin, epigallocatechin, caffeic acid, ferulic acid, several lignans and 4-methyl-5-thiazoleethanol. The differential secondary metabolites were mainly annotated and enriched in the flavonoid biosynthesis pathway and the flavone and flavonol biosynthesis pathway.