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基于广泛靶向代谢组学分析9种蝴蝶兰挥发性代谢物差异
Differential Volatile Metabolites in Nine Phalaenopsis Orchid Species Based on Broad-Targeted Metabolomics Analysis
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摘要: 为挖掘蝴蝶兰原生种中与香气形成相关的关键代谢物和通路,筛选优良芳香亲本并鉴定可用于分子育种的靶点基因,以恢复和改良栽培蝴蝶兰的芳香性状。对9种蝴蝶兰原生种盛花期花部组织进行GC-MS广泛靶向代谢组分析,结果表明:共鉴定214种次生代谢物,主要为有机酸及其衍生物(56.3%)、苯及取代衍生物(21.5%)和脂质类(12.0%)。PCA与聚类分析显示物种间代谢谱显著分化(累计贡献率44.2%)。其中,苯乙醛在菲律宾蝴蝶兰中特异性高积累(4.18%),其余种类未检出或极低;结合其极低气味阈值(~0.02 ppb),提示其为关键香气成分。KEGG富集分析表明,苯丙氨酸代谢、碳代谢及苯丙素合成通路显著富集。尽管本研究基于组织提取反映的是潜在香气前体库,但仍明确了驱动香气多样性的核心代谢模块。菲律宾蝴蝶兰可作为优良芳香亲本,苯丙氨酸通路关键酶基因可作为分子育种或代谢工程靶点,用于定向改良栽培蝴蝶兰香气品质。Abstract: To explore the key metabolites and pathways related to the formation of fragrance in the native species of Phalaenopsis and to screen for superior fragrant parents and identify target genes for molecular breeding, thereby restoring and improving the fragrant traits of cultivated Phalaenopsis. In this study, GC-MS wide-targeted metabolomic analysis was conducted on the floral tissues of nine native Phalaenopsis species at full bloom. A total of 214 secondary metabolites were identified, mainly including organic acids and their derivatives (56.3%), benzene and its substituted derivatives (21.5%), and lipids (12.0%). PCA and cluster analysis showed significant metabolic profile differentiation among species (cumulative contribution rate of 44.2%). Among them, phenylacetaldehyde was highly accumulated in Phalaenopsis philippinensis (4.18%), while it was undetectable or present at extremely low levels in the other species. Considering its extremely low odor threshold (~0.02 ppb), it is suggested to be a key fragrant component. KEGG enrichment analysis indicated that phenylalanine metabolism, carbon metabolism, and phenylpropanoid biosynthesis pathways were significantly enriched. Although this study was based on tissue extraction and reflected the potential fragrance precursor pool, it still clarified the core metabolic modules driving fragrance diversity. Phalaenopsis philippinensis can be used as an excellent fragrant parent, and key enzyme genes in the phenylalanine pathway can be used as targets for molecular breeding or metabolic engineering to improve the fragrance quality of cultivated Phalaenopsis in a targeted manner.
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