南昌城市湖泊浮游真菌群落组成、共生模式及影响因素

Community Composition,Symbiotic Patterns,and Influencing Factors of Planktonic Fungi in Urban Lakes of Nanchang

为探明南昌湖泊浮游真菌群落特征和环境胁迫对浮游真菌群落的影响机制,分别于枯水期(2月、12月)、平水期(4月、10月)和丰水期(6月、8月)采集了均匀分布于南昌市不同县级区划下的7个主要城市湖泊表层水样.测定了WT、DO、NH_(4)^(+)-N和NO_(3)^(-)-N等环境胁迫因子指标,基于高通量测序研究浮游真菌群落特征,运用网络分析等方法阐明浮游真菌群落的共生模式,并揭示影响浮游真菌群落结构和共生模式的环境胁迫因子.结果表明:①南昌湖泊浮游真菌群落组成在水期间具显著差异,在各湖泊间差异不显著.WT、DO、pH和NH_(4)^(+)-N是影响浮游真菌群落组成的显著环境胁迫因子.②浮游真菌群落优势门为Chytridiomycota(9.55%~33.14%)、Basidiomycota(0.48%~4.25%)和Ascomycota(1.29%~3.19%),优势菌门数量大小为:丰水期>平水期>枯水期,Chytridiomycota相对丰度在丰水期显著高于平水期和枯水期,Basidiomycota相对丰度在枯水期显著低于平水期和丰水期,Ascomycota水期差异不显著.③南昌湖泊浮游真菌群落共生网络稳定性大小为:丰水期>平水期>枯水期,WT是影响浮游真菌群落共生模式的最佳环境胁迫因子.研究可为湖泊的综合评价和治理研究提供理论依据,并为长江中下游地区湖泊生态系统保护提供指导.

To investigate the characteristics of planktonic fungal communities in Nanchang lakes and the mechanism of environmental stress on planktonic fungal communities,surface water samples were collected from seven major urban lakes evenly distributed in different county-level districts of Nanchang in the dry(February and December),normal(April and October),and wet(June and August)seasons,respectively.The environmental stressors such as WT,DO,NH_(4)^(+)-N,and NO_(3)^(-)-N were measured;the characteristics of planktonic fungal communities were studied using high-throughput sequencing;the symbiotic patterns of planktonic fungal communities were elucidated using network analysis and other methods;and the environmental stressors affecting the structure and symbiotic patterns of planktonic fungal communities were revealed.The results showed that①the planktonic fungal community composition in lakes of Nanchang varied significantly among seasons but not significantly among the lakes.WT,DO,pH,and NH_(4)^(+)-N were the significant environmental stressors affecting the planktonic fungal community composition.②The dominant phyla of the planktonic fungal community were Chytridiomycota(9.55%-33.14%),Basidiomycota(0.48%-4.25%),and Ascomycota(1.29%-3.19%),and the sizes of the dominant phyla were in the following order:wet season>normal season>dry season.The relative abundance of Chytridiomycota was significantly higher in the wet season than that in the normal season and the dry season,the relative abundance of Basidiomycota was significantly lower in the dry season than that in the normal and wet seasons,and the difference in Ascomycota among seasons was not significant.③The stability size of the planktonic fungal community symbiosis network in lakes of Nanchang was in the following order:wet season>normal season>dry season.WT was the best environmental stressor affecting the planktonic fungal community symbiosis pattern.The study can provide theoretical basis for the comprehensive evaluation and management study of the lake and provide guidance for protecting the lake ecosystem in the middle and lower reaches of the Yangtze River.