【摘要】 为了探究土地利用变化对湿地系统土壤细菌的影响,以会仙天然湿地、稻田和旱地这3种土地利用方式的耕层土壤(0～20cm)作为研究对象,利用高通量测序技术对土壤细菌群落的α多样性、物种组成和丰度进行分析,并结合土壤理化性质探讨影响细菌群落结构的环境因素.结果表明,会仙湿地系统土壤中存在的细菌隶属于49个门和145个纲.其中,稻田土壤细菌的Shannon指数显著较高;天然湿地土壤细菌的Simpson指数显著较低.在会仙湿地系统土壤的优势菌门(operational taxonomic units,OTUs> 1%)中,天然湿地的优势菌门为变形菌门(52. 15%)、放线菌门(15. 16%)和酸杆菌门(8. 80%);稻田的优势菌门为变形菌门(45. 79%)、酸杆菌门(17. 20%)和绿弯菌门(11. 75%);旱地的优势菌门为变形菌门(51. 42%)、酸杆菌门(15. 51%)和绿弯菌门(7. 43%).在优势菌纲(OTUs> 1%)中,天然湿地的优势菌纲为α-变形菌纲(17. 98%)、β-变形菌纲(13. 72%)和放线菌纲(13. 13%);稻田的优势菌纲为酸杆菌纲(14. 35%)、β-变形菌纲(13. 37%)和δ-变形菌纲(12. 02%);旱地的优势菌纲为α-变形菌纲(19. 44%)、β-变形菌纲(13. 30%)和酸杆菌纲(13. 03%).在优势的OTUs中(> 0. 3%),天然湿地的优势菌属是Sphingomonas(OTU2和59)、Micromonospora(OTU5、24和50487)、Gemmatimonas(OTU1)和Stenotrophomonas(OTU8);稻田的优势菌属是Lysobacter(OTU4和115)和Aquabacterium(OTU33);旱地的优势菌属是Sphingomonas(OTU85、157和2916)、Rhodanobacter(OTU19和52)和Phenlobacterium(OTU60).聚类热图分析显示,3种土地利用下的土壤细菌群落结构差异极其显著.冗余分析结果显示,土壤细菌分布差异主要与p H、土壤总有机碳(SOC)、全氮(TN)、碱解氮(AN)、交换性镁、交换性钙、可溶性有机碳(DOC)和速效磷(AP)等生态因子显著相关(P <0. 05).以上研究结果表明,土地利用方式变化能显著改变会仙湿地土壤的细菌群落结构.更多还原

【Abstract】 In order to explore the effect of land-use change on soil bacteria in wetland systems,the topsoil( 0-20 cm) of a natural wetland( NW),paddy field( PF),and dry land( DL) were collected in the Huixian karst wetland. The α-diversity,species composition,and abundance of soil bacterial communities were analyzed using high-throughput sequencing. The effect of environmental factors on bacterial community structure was also examined. The results showed that the soil bacteria in the Huixian karst wetland can be divided into 49 phyla and 145 classes. The Shannon index of bacteria in the PF was significantly higher,and the Simpson index of bacteria in the NW is significantly lower,than in the other two land-use types. The dominant phyla( operational taxonomic units,OTUs> 1%) in the NW were Proteobacteria( 52. 15%),Actinobacteria( 15. 16%),and Acidobacteria( 8. 80%); the dominant phyla in the PF were Proteobacteria( 45. 79%),Acidobacteria( 17. 20%),and Chloroflexi( 11. 75%); the dominant phyla in the DL were Proteus( 51. 42%),Acidobacteria( 15. 51%),and Chloroflexi( 7. 43%). The dominant classes( OTUs > 1%) in the NW were α-Proteobacteria( 17. 98%),β-Proteobacteria( 13. 72%),and Actinobacteria( 13. 13%); the dominant classes in the PF were Acidobacteria( 14. 35%),β-Proteobacteria( 13. 37%),and δ-Proteobacteria( 12. 02%); the dominant classes in the DL were α-Proteobacteria( 19. 44%),Formobacteria( 13. 30%),and Acidobacteria( 13. 03%). Among the dominant OTUs( > 0. 3%),the dominant genera of in the NW were Sphingomonas( OTU2,59),Micromonospora( OTU5,24 and 50487),Gemmatimonas( OTU1),and Tenotrophomonas( OTU8); the dominant genera in the PF were Lysobacter( OTU4 and 115) and Aquabacterium( OTU33); the dominant genera in the DL were Sphingomonas( OTU85,157 and 2916),Rhodanobacter( OTU19 and 52),and Penlobacterium( OTU60). A heatmap showed that there were significant differences in soil bacterial community structure among the three land-use types. Redundancy analysis showed that p H,soil organic carbon( SOC),total nitrogen( TN),alkali-hydrolyzable nitrogen( AN),exchangeable Mg2 +,exchangeable Ca2 +,soluble organic carbon( DOC),and available phosphorus( AP) were the main factors that affected the bacterial community structure in the Huixian karst wetland. These results indicate that changes in land-use types have significantly shaped the structure of soil bacterial communities in this area.更多还原