贵州喀斯特山区不同种植年限花椒根际土壤细菌群落结构特征研究

以贵州花江峡谷花椒(Zanthoxylum bungeamun)林为研究对象,采用16S rRNA高通量测序技术,分析种植5、10、20、30 a花椒根际土壤细菌群落结构和多样性特征,探讨不同种植年限花椒土壤理化因子对根际细菌群落分布的影响,为喀斯特石漠化地区花椒农业可持续发展提供有效的理论依据。结果表明,随着花椒种植年限的增加,土壤含水率、pH和有效磷逐渐升高,有机质、铵态氮和硝态氮含量先降低后升高(P<0.05)。根际土壤细菌Shannon、Simpson指数总体呈现上升趋势,OTUs、Chao1指数在10a较低。PCo A分析显示,不同种植年限花椒根际细菌群落组成差异显著,并且随着年限的增加,群落结构趋于相似;差异指示种分析表明,5—30a差异指示种分别为Firmicutes(厚壁菌门)、Cyanobacteria(蓝藻菌门)、Planctomycetes(浮霉菌门)、Entotheonellaeota(肠杆菌门)。RDA分析表明,有机质和含水率与细菌群落分布显著相关(P<0.05)。系统发育多样性分析表明,丰富类群多样性与环境因子存在较多的正相关,稀有类群比丰富类群有更强的发育信号。Bug Base预测分析发现:随着年限增加根际土壤好氧细菌增加,厌氧细菌下降,5、10 a氧化胁迫耐受菌低于20、30 a,致病菌在5、10 a高于20、30 a。综上,种植年限影响了花椒根际土壤细菌群落多样性,不同年限根际土壤肥力不同使得土壤细菌选择性生长,随着一定时间发育花椒抗病能力提高。

Structural Characteristics of Bacterial Community in Rhizosphere Soil of Zanthoxylum bungeamun in Different Planting Years in Karst Areas of Guizhou

To examine the effects of different cultivation history(5 a,10 a,20a and 30 a)on soil microbial communities,16S rRNA Illumina sequencing was used to investigate the diversity and structure of soil bacterial communities from Zanthoxylum Forest in Huajiang Canyon,Guizhou.The results showed that with the increase of the years of planting Zanthoxylum,soil moisture content,pH and available phosphorus gradually increased,and organic matter,ammonium nitrogen and nitrate nitrogen decrease first and then increase(P<0.05).With the increase of Zanthoxylum bungeanum planting years,the Shannon and Simpson indexes of rhizosphere soil bacteria showed an overall upward trend,and the OTUs and Chao1 indexes are lower in 10 a;PCoA analysis manifested that the composition of the bacterial community in the rhizosphere of Zanthoxylum bungeanum was significantly different in different planting years,and the community structure tended to be similar as the years increased.Pheatmap analysis indicated that the 5 a differential indicator species is Firmicutes,10 a is Cyanobacteria,20 a is Planctomycetes,and 30 a is Entotheonellaeota.The RDA analysis of organic matter and soil moisture content is significantly related to the distribution of bacterial communities(P<0.05).Phylogenetic diversity analysis suggested that there are more positive correlations between abundant taxa and environmental factors,and rare taxa have higher developmental signals than abundant taxa.The BugBase phenotype prediction analysis found that as the age increases,aerobic bacteria in the rhizosphere soil increase,and anaerobic bacteria are declined,5 a,10 a stress tolerant bacteria are lower than 20 a,30 a,and pathogenic bacteria at 5 a,10 a are higher than 20 a,30 a.In summary,the predominant factors affecting soil microbial communities were the cultivation history.Different years of rhizosphere soil fertility makes the soil bacteria grow selectively,and the disease resistance of Zanthoxylum bungeanum increases with a certain period of time.