广西莪术不同组织内生真菌多样性、环境适应性与药用成分积累的关系

Diversity, environmental adaptation, and medicinal component accumulation of endophytic fungi in different tissues of Curcuma kwangsiensis

关键词:  广西莪术, 内生真菌, 高通量测序, 组织特异性, 土壤理化性质

Key words:  Curcuma kwangsiensis, endophytic fungi, high-throughput sequencing, tissue specificity, soil physicochemical properties

摘要:

广西莪术(Curcuma kwangsiensis)为姜科姜黄属道地药材,其药材品质形成机制尚未明晰。为了解析内生真菌群落与土壤环境及药材品质的互作关系,揭示其道地性形成的微生物学基础,该研究选取钦州浦北县、灵山县和钦南区3个主产区的广西莪术样本,采用ITS高通量测序和化学分析方法,系统研究5个组织(根、根茎、茎、叶、花)的内生真菌群落结构,分析根际土壤理化性质和药材品质标记物,并通过冗余分析(RDA)和相关性分析探究菌群-环境因子-药材品质的关联。结果表明:(1)45份样本共获得2 357个操作分类单元(OTU)(902种真菌); 3个产区OTU分布差异显著,共有核心OTU占比为19.4%; 叶组织OTU总数(1 205)及特有OTU数量(415)最多,5个组织共有OTU占比仅6.9%。(2)地上组织(叶、花)真菌丰富度(ACE指数和Chao 1指数)和多样性(Shannon指数)显著高于地下组织(根、根茎)且群落结构差异明显(NMDS分析)。(3)核心属分析显示,地下组织以粪壳菌纲未分类物种(unclassified-c—Sordariomycetes)和木腐菌等为主要类群,地上组织以枝孢属(Cladosporium)和链格孢属(Alternaria)等为优势属,茎组织呈现过渡特征。(4)RDA分析表明,土壤pH、有机质及养分(氮、磷、钾)显著影响菌群组成; 浦北县根茎样品莪术醇溶浸出物含量(ASEC)最高,其中根茎菌群与ASEC密切相关且其根茎中粪壳菌纲未分类物种与ASEC呈正相关,枝顶孢属(Acremonium)与ASEC呈负相关。综上认为,广西莪术内生真菌群落具有显著的地域特异性和组织生态位分异特征,特定真菌类群可能通过微环境调控参与药用成分积累,这为道地药材品质形成的微生物机制研究提供了新视角。

Abstract:

Curcuma kwangsiensis is a Daodi medicinal material of Curcuma in Zingiberaceae, yet the mechanism underlying its quality formation remains unclear. To elucidate the interaction relationships between endophytic fungal communities, soil environments, and medicinal material quality and to reveal the microbiological basis of its geographical authenticity. C. kwangsiensis samples were collected from three major production areas in Qinzhou City(Pubei County, Lingshan County, and Qinnan District). Using ITS high-throughput sequencing and chemical analysis methods, the endophytic fungal community structures across five tissues(root, rhizome, stem, leaf, and flower)were systematically studied, and the physicochemical properties of the rhizosphere soil and quality markers of the medicinal materials were analyzed. Redundancy analysis(RDA)and correlation analysis were employed to explore the relationships between microbial communities, environmental factors, and medicinal material quality. The results were as follows:(1)A total of 2 357 operational taxonomic units(OTUs)(902 species of fungi)were obtained from 45 samples; the distribution of OTUs among the three regions differed significantly, with only 19.4% being common core OTUs across regions; leaf tissues harbored the highest number of total OTUs(1 205)and unique OTUs(415), while the shared OTUs among the five tissue types accounted for only 6.9%.(2)Above-ground tissues(leaf and flower)exhibited significantly higher fungal richness(ACE and Chao 1 indexes)and diversity(Shannon index)than below-ground tissues(root and rhizome). Additionally, NMDS analysis revealed distinct differences in community structures between above-ground and below-ground tissues.(3)The core genus analysis indicated that the below-ground tissues were dominated by taxa such as unclassified-c—Sordariomycetes and wood-decomposing fungi, while the above-ground tissues were characterized by dominant genera like Cladosporium and Alternaria. The stem tissues displayed transitional characteristics in their fungal composition.(4)The RDA demonstrated that soil pH, organic matter, and nutrients(nitrogen, phosphorus, and potassium)significantly influenced the fungal community composition; rhizome samples from Pubei County showed the highest olibanum alcohol-soluble extract content(ASEC). Notably, the rhizome fungal community was closely associated with ASEC levels, and unclassified-c—Sordariomycetes in rhizomes showed a positive correlation with ASEC, whereas Acremonium exhibited a negative correlation with ASEC. The above results indicate that the endophytic fungal community in Curcuma kwangsiensis exhibits significant regional specificity and tissue niche differentiation characteristic. Specific fungal taxa may participate in the accumulation of medicinal compounds through microenvironmental regulation, providing new insights into the microbial mechanisms underlying the formation of Daodi medicinal material quality.