基于eDNA宏条形码的草海沉积物蓝藻群落季节动态研究

Seasonal dynamics of cyanobacteria community in Caohai sediments based on eDNA metabarcoding

为监测贵州草海沉积物中蓝藻群落结构随季节的动态变化规律,分4个季节采集草海沉积物样品,利用eDNA宏条形码技术,分析蓝藻的群落结构组成及季节动态变化。结果表明,4个季节中草海沉积物原核生物群落主要由绿弯菌门、放线菌门及变形菌门构成;蓝藻门在原核生物中的丰度占比为0.99%~5.69%,4个季节中的平均相对丰度为2.53%。在科分类阶元上,草海蓝藻主要有norank Chloroplast、Cyanobiaceae、念珠藻科(Nostocaceae)、Desertifilaceae、席藻科(Phormidiaceae)、微囊藻科(Microcystaceae)、细鞘丝藻科(Leptolyngbyaceae)、颤藻科(Oscillatoriaceae)、伪鱼腥藻科(Pseudanabaenaceae)、蓝菌科(Cyanobacteriaceae)、聚球藻科(Synechococcaceae)。在属分类阶元上,蓝藻优势属主要为norank_f_norank_o_Chloroplast、双色藻属(Cyanobium)、念珠藻属(Nostoc)、浮丝藻(Planktothrix)、拟浮丝藻属(Planktothricoides)、微囊藻属(Microcystis)、微鞘藻属(Microcoleus)、拟圆孢藻属(Sphaerospermopsis)、Roseofilum属等。春夏季时草海有害蓝藻类群少,秋冬季时有害蓝藻类群占比较高;此外,秋冬季时蓝藻OTUs数、物种种类数及相对丰度均较春夏季高。这表明,秋冬季时草海蓝藻群落丰度高、物种丰富、有害类群多,水华风险不容小觑。在后续研究中可利用eDNA宏基因组方法监测湖泊藻类群落结构、生物多样性及功能基因动态演变。

To monitor the seasonal dynamics of cyanobacteria community in Caohai sediments,sediment samples were collected in four seasons,and the community structure and seasonal dynamics of cyanobacteria were analyzed by using eDNA metabarcoding technology.The results showed that the prokaryotes in Caohai sediments were mainly Chloroflexi,Actinomyces,and Proteobacteria.The abundance of cyanobacteria in prokaryotes ranged from 0.99%to 5.69%,with an average relative abundance of 2.53%in the four seasons.At the family level,norank Chloroplast,Cyanobiaceae,Nostocaceae,Desertifilaceae,Phormidiaceae,Microcystaceae,Leptolyngbyaceae,Oscillatoriaceae,Pseudanabaenaceae,Cyanobacteriaceae,and Synechococcaceae were the dominant groups.At the genus level,the dominant genera were norank_f_norank_o_Chloroplast,Cyanobium,Nostoc,Planktothrix,Planktothricoides,Microcystis,Microcoleus,Sphaerospermopsis,Roseofilum,etc.There were fewer harmful cyanobacteria in spring and summer,and more harmful cyanobacteria in autumn and winter.the OTUs number,species number,and relative abundance of cyanobacteria were higher in autumn and winter than those in spring and summer.The results indicated that in autumn and winter,the abundance of cyanobacteria was higher,the harmful species were richer,and the risk of cyanobacterial bloom should not be underestimated.In future studies,the eDNA metagenomic method can be used to monitor the dynamic evolution of lake algae community structure,biodiversity,and functional genes.