鹤山地区健康和失管茶园土壤真菌群落结构差异及其驱动因子分析

Differences of soil fungal community structure and driving factors between healthy and mismanaging tea plantations in Heshan of southern China

摘要:

【目的】以鹤山红茶产地生态系统为研究对象，探究健康和失管茶园中土壤真菌群落结构的差异以及土壤理化性质对真菌群落结构的影响。【方法】在鹤山地区健康茶园和管理不善的失管茶园中采集了49份根围土壤样品，采用高通量测序技术分析茶树根围土壤真菌的群落组成；利用冗余分析研究土壤理化性质对真菌群落结构的影响；进一步通过wilcoxon秩和检验法分析健康和失管茶园中差异的真菌类群；通过FUNGuild软件对土壤真菌的功能类群进行预测。【结果】研究发现担子菌门、被孢霉门和子囊菌门是茶树根围土壤的优势门；失管茶园中担子菌门的相对丰度显著升高，而被孢霉门则显著降低；根围土壤真菌的丰富度指数、Chao1指数和ACE指数显著低于健康茶园。研究发现总氮、总磷、有效磷、有机质和水解性氮是真菌β多样性差异的主要环境驱动因子；pH、总磷、交换性镁、交换性钙、有效磷和有效钾等与真菌类群间存在显著的相关性。健康和失管茶园中共有的核心操作分类单元(operational taxonomic units, OTUs)是10个，失管茶园中核心类群的相对丰度降低，而中间类群和稀有类群的相对丰度则增加。健康茶园根围土壤核心OTUs中出现了茶轮斑病菌茶拟盘多毛孢和国槐根腐病菌角化可塑镰孢菌(Fusarium keratoplasticum)，失管茶园根围土壤核心OTUs中生防菌螺旋木霉(Trichoderma spirale)、深绿木霉(T. atroviride)的丰度显著较高。失管茶园中病原营养型、病原-腐生-共生过渡型和共生营养型真菌的相对丰度明显增加；而腐生-共生过渡型的真菌则显著降低。【结论】本研究揭示了鹤山地区茶园管理方式与真菌群落结构和土壤理化性质间的关系，为鹤山红茶的病害防治及生防菌筛选指明了方向。

Abstract:

[Objective] This study aims to investigate the soil fungal community structure in the tea plantations of Heshan and explore the relationship between fungal community and soil physicochemical properties. [Methods] We employed high-throughput sequencing to analyze the soil fungal community composition of 49 rhizosphere soil samples collected from healthy and mismanaging tea plantations in Heshan. The redundancy analysis (RDA) was performed to analyze the effects of soil physicochemical properties on the fungal community structure. The pairwise Wilcoxon signed-rank test was performed to compare the fungal taxa between the two kinds of tea plantations. FUNGuild was used to predict the soil fungal functions. [Results] Basidiomycota, Mortierellomycota, and Ascomycota were the three dominant phyla in the rhizosphere soil of tea plantations in Heshan. The mismanagement of tea plantations increased the relative abundance of Basidiomycota, but significantly decreased the relative abundance of Mortierellomycota. The fungal richness, Chao1 index, and ACE index were significantly lower in the mismanaging tea plantation than in the healthy tea plantation. The total nitrogen, total phosphorus, available phosphorus, organic matter, and available nitrogen were the primary driving factors for the differences of soil fungal β diversity. The soil pH, total phosphorus, exchangeable Ca²⁺ and Mg²⁺, available phosphorus, and available potassium were significantly correlated with the fungal taxa. Compared with the healthy tea plantation, the mismanaging tea plantation showed decreased relative abundance of core fungal taxa but increased relative abundance of medium and rare taxa. Ten of OTUs was common between healthy and mismanaging tea plantations. The pathogens causing tea gray blight, i.e., Pseudopestalotiopsis theae and Fusarium keratoplasticum, were identified in the healthy tea plantation. The relative abundance of biocontrol fungi, Trichoderma spirale and T. atroviride, significantly increased in the mismanaging tea plantation. The mismanaging tea plantation demonstrated increased relative abundance of pathotrophic, pathotrophic-saprotrophic-symbiotrophic, and symbiotrophic fungi but decreased relative abundance of saprotrophic-symbiotrophic fungi. [Conclusion] We elucidated the relationship of management mode with fungal community composition and soil physicochemical properties, providing the insights into the prevention and control of pathogens infecting black tea and the screening of biocontrol fungi in Heshan.