泡桐丛枝病对内生真菌群落及其结构的影响

Effects of Paulownia witches’broom disease on fungal endophytes community and structure

【目的】探讨泡桐丛枝病对泡桐内生真菌群落结构的影响。【方法】采集了患丛枝病泡桐和健康泡桐的枝、叶和根样品,通过高通量测序技术结合机器学习法研究了丛枝病对泡桐内生真菌群落结构以及关键真菌物种的影响。【结果】病树的枝和根中均含有植原体,但只有地上部表现出丛枝病症状。生境(采样部位)和健康状况均是影响泡桐内生真菌群落结构的重要影响因素。丛枝病对泡桐枝、叶和根的内生真菌群落α多样性影响有限,但是显著改变了枝和叶的β多样性。在泡桐的枝、叶和根中,子囊菌门(Ascomycota)是丰度最高的门,其次为担子菌门(Basidiomycota)。丛枝病提高了枝和叶中担子菌门的丰度,而降低了子囊菌门的丰度;在根中,丛枝病降低了担子菌门的丰度,而提高了子囊菌门的丰度。通过机器学习法鉴定出10个关键的真菌物种,其中棒孢属(Corynespora)、枝孢属(Cladosporium)和Nigrospora均属常见的致病真菌,其丰度在发病的枝或叶中均显著高于健康样品,推断这些致病真菌可能加剧了丛枝病的发病程度。【结论】明确了泡桐丛枝病对泡桐内生真菌群落结构的影响,进而为泡桐丛枝病的防治奠定了理论基础。

【Objective】To investigate the effects of witches’broom on fungal endophytes community structure in Paulownia.【Method】In this study,branch,leaf and root samples of Paulownia with and without witches’broom were collected,and the effects of witches’broom on fungal endophytes community structure and key fungal species of Paulownia were studied by high-throughput sequencing techniques combined with random forest machine learning methods.【Result】Phytoplasmas presented in the both branches and roots,but only the aboveground part showed the symptoms of witches’broom.Both habitat(sampling site)and health status were important factors affecting the community structure of fungal endophytes in Paulownia.Arbuscular disease had limited effect onαdiversity of endophytic fungal endophytes in the branches,leaves and roots of Paulowia,but significantly changedβdiversity in the branches and leaves.Among the branches,leaves and roots of Paulownia,Ascomycota was the most abundant phylum,followed by Basidiomycota.Witches’broom increased the abundance of Basidiomycota in branches and leaves,but decreased the abundance of Ascomycota.In the roots,witches’broom decreased the abundance of Basidiomycota and increased the abundance of Ascomycota.Ten key fungal species were identified by random forest machine learning methods,among which Corynespora,Cladosporium and Nigrospora were all common pathogenic fungi,and their abundance in diseased branches or leaves was significantly higher than that in healthy samples.It is speculated that these pathogenic fungi might aggravate the incidence of witches’broom.【Conclusion】In this study,the effects of witches’broom on fungal endophytes community structure of Paulownia were clarified,which laid a theoretical foundation for the prevention and treatment of witches’broom in Paulownia.