酸性矿山5种植被恢复措施下土壤碱性磷酸酶基因细菌群落特征及其与重金属关系

Characteristics of soil pho D bacterial community and their relationship with heavy metals under five vegetation restoration in acid mines

为揭示酸性矿山不同植被恢复措施下碱性磷酸酶基因(pho D)细菌群落特征及其与重金属的关系,以赣州龙南稀土矿区为研究区域,收集了5种植被(百喜草、香根草、桉树、玉兰、芥兰)的土壤,测量不同植被土壤理化性质和重金属含量,利用高通量测序技术分析16S rRNA细菌和pho D基因细菌多样性及其群落特征,并计算pho D基因细菌与重金属含量的相关性.结果表明:不同植被土壤存在Cd、As、Pb、Mn超过江西省背景值现象,其中桉树、香根草土壤Pb含量分别为背景值的5.96倍、4.4倍,桉树土壤Cd含量为背景值的2.6倍.pho D基因细菌多样性Chao1指数排序为百喜草<香根草<桉树<玉兰<芥兰.慢生根瘤菌属(Bradyrhizobium)、假单胞菌属(Pseudomonas)、链霉菌属(streptomyces)为主要pho D基因菌属.相关性分析结果表明,Cd、As、Mn含量与铵态氮、硝态氮呈显著正相关,Cd、As、Pb同pho D基因细菌Chao1指数呈显著负相关,pH、TN、OM、TP、AP与pho D基因细菌多样性呈显著正相关.Heatmap热图显示,新根瘤菌属(Neorhizobium)、kribbella、浮霉状菌属(Planctomyces)、微枝形杆菌属(Microvirga)、紫色杆菌属(Janthinobacterium)、粘杆菌属(Gloeobacter)、Luteolibacter菌属与Pb含量呈显著负相关,孢囊链霉菌属(Streptosporangium)与Cd、As呈显著负相关,慢生根瘤菌属(Bradyrhizobium)、固氮螺旋菌属(Azospirillum)、Singulisphaera与Mn呈显著负相关.研究结果显示,固氮根瘤、放线菌等类pho D基因细菌与Cd、As、Pb、Mn含量相关性更为明显,本研究可为科学认识土壤重金属与pho D基因细菌关系提供依据.

The rare earth mining areas in Longnan county,Ganzhou city,were selected to investigate the characteristics of alkaline phosphatase gene(phoD)-harboring microbial community in acid mines under the effects of different heavy metals and vegetation restoration,soils under five vegetation(Bahia grass,vetiver,eucalyptus,magnolia and spring cabbage)were measured for their physicochemical properties and heavy metal contents.16S rRNA gene and phoD in the soils were analyzed with High-throughput sequencing technology.The correlations between phoD-harboring bacteria and heavy metal contents were also calculated.Results showed that Cd,As,Pb and Mn in the soils exceeded the background values in Jiangxi Province.The content of Pb in eucalyptus and vetiver soil were 5.96 times and 4.4 times higher than that in the background,respectively.Cd content in eucalyptus soil was 2.6 times higher than the background value.The order of Chao1 index for phoD-harboring microbial diversity was Bahia grass<Vetiver grass<eucalyptus<Magnolia<spring cabbage.The main phoD genera were Bradyrhizobium,Pseudomonas and Streptomyces.Correlation analysis results showed that Cd,As and Mn were positively correlated with ammonium and nitrate nitrogen.Cd,As,Pb were negatively correlated with the Chao1 index.PH,TN,OM,TP,AP were positively correlated with the bacterial diversity of phoD.The correlation heatmap shows that bacteria such as Neorhizobium,Kribbella,Planctomyces,Microvirga,Janthinobacterium,Gloeobacter,Luteolibcter were significantly negatively correlated with Pb.Streptosporangium was significantly negatively correlated with Cd and As.Bradyrhizobium,Azospirillum and Singulisphaera were significantly negatively correlated with Mn.The conclusion showed that the correlation between phoD-harboring bacteria,such As nitrogen-fixing,actinomycetes,and Cd,As,Pb,Mn were more obvious.This study provides a basis for scientific understanding of the relationship between heavy metals and phoD gene-harboring bacteria in soils.