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    不同病斑等级的西伯利亚红松针叶内生真菌多样性和菌群结构分析

    Diversity and community structure of endophytic fungi in Pinus sibirica needles with different disease spot grades

    • 摘要:
      目的 研究不同病斑等级的西伯利亚红松针叶中内生真菌的多样性和菌群结构,为西伯利亚红松生物防治提供理论依据。
      方法 对西伯利亚红松针叶中的真菌进行高通量测序,并进行α和β多样性分析,利用Spearman相关性系数深入分析真菌间相关性,采用FUNGuild数据库预测真菌营养类群。
      结果 (1)α和β多样性分析表明,健康针叶内生真菌多样性丰富,与感病针叶相比,内生真菌多样性差异性显著,而不同病斑等级的针叶多样性差异不显著,在发病后期针叶内生真菌群落多样性相似度较高。(2)真菌群落LEfSe分析表明健康叶片PM1样品组中的差异指示类群最多(19个)。(3)群落结构分析表明与感病针叶内生真菌群落结构相比,健康针叶PM1中内生真菌群落结构较复杂,其中镰刀菌属占主要地位;不同病斑等级的西伯利亚红松针叶真菌群落结构也存在差异,其中在轻度染病的针叶PM2中43.94%的优势内生真菌为拟青霉属;随着病斑等级的加深,PM3、PM4和PM5优势内生真菌为穴褥盘孢菌属,其中丰度最高的内生真菌为松穴褥盘孢属。(4)已染病的针叶与健康针叶相比内部内生真菌营养类群发生明显变化,健康针叶内生真菌群落营养类型相对丰度较为均匀,随着病斑等级的增加,针叶内部内生真菌群落营养型从病理型向腐生型转变,且存在大量未知功能菌群。
      结论 在不同病斑等级的西伯利亚红松针叶内,内生真菌的多样性及其菌群结构存在显著差异(P < 0.05)。在健康的针叶内,内生菌的多样性指数最高、指示类群最多。但是随着病斑面积的增加,针叶中的营养型内生真菌从病理型真菌向腐生型真菌转变。

       

      Abstract:
      Objective The diversity and flora structure of endophytic fungi in the needles of Pinus sibirica with different plaque grades were studied to provide a theoretical basis for the microecological control of Siberian red pine diseases.
      Method The fungi in needles of P. sibirica were sequenced by high-throughput sequencing method, α and β diversity were analyzed by Spearman correlation coefficient, and fungal trophic groups were predicted by FUNGuild database.
      Result (1) α and β diversity analysis showed that the endophytic fungal diversity in asymptomatic needle leaves was higher, and the diversity of endophytic fungi was significantly different from infected needles. There was no significant difference in needle leaf diversity among different disease spot grades, and the diversity of endophytic fungal communities of needle leaves was more similar in later stages of the disease. (2) Fungal community LEfSe analyses showed the highest number of significant biomarkers (19) in the PM1 sample group of asymptomatic needle leaves. (3) Community structure analysis showed that, compared with the endophytic fungal community structure of infected needle leaves, the endophytic fungal community structure of asymptomatic needle leaves PM1 was more complex, in which Fusarium spp. was dominated; there were also differences in the fungal community structure of P. sibirica needle leaves with different disease spot grades, in which 43.94% of the dominant endophytic fungi in mildly infected needles PM2 were Penicillium spp. and as the spot grades deepened, the dominant endophytic fungus in PM3, PM4 and PM5 was Dothistroma spp. One of the most abundant endophytic fungi was Dothistroma spp. (4) The internal endophytic fungal trophic classification of diseased needle leaves changed significantly compared with asymptomatic needles. The relative abundance of endophytic fungal trophic classification in asymptomatic needle leaves was relatively uniform, and as the level of diseased spots increased, the internal endophytic fungal trophic classification in needle leaves shifted from pathological fungi to saprophytic fungi, and a large number of unknown functional fungal groups existed.
      Conclusion The diversity and community structure of endophytic fungi are significantly different (P < 0.05) in the needles of Pinus sibirica with different plaque grades. In healthy needles, Endophytic bacteria have the highest diversity index and most indicator groups. However, with the increase of lesion grade, the nutrient type of endophytic fungi community changes from pathological type to saprophytic type.

       

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