Soil Microbial Community Structures Of The 5 Land-use Types In Huixian Karst Wetland

In order to explore the effect of land-use change on soil microorganism in wetland system,the topsoils(0-20cm)of wetland with phragmites communis(PC)and with cyperus rotundus(CR),abandoned paddy fields(APF),paddy field(PF)and dry land(DL)were collected in Huixian karst wetland.The α-diversity,species composition and abundance of soil bacterial community were analyzed based the data from high-throughput sequencing technology.The effect of environmental factors on the bacterial community structure was also discussed.The main results were as followed.(1)The bacterial diversity of PF was the highest under five land-use types.The dominant phylum of reed wetland and Huakola grass wetland were Proteus,Actinomycetes and Acidobacteria.The dominant phylum of APF was Proteus,Actinomycetes and Curvularia.The dominant phyla of PF and DL were Proteus,Acidobacteria and Curvularia.Among the dominant OTUs,Sphingomonas(OTU2,28 and 59),Micromonospora(OTU5,24 and 50487),Arthrobacter(OTU10)and Gemmatimonas(OTU1)were the dominant bacteria in PC and CR.The dominant genera of APF were Arthrobacter(OTU10).The dominant genera in PF were Azospirillum(OTU15),Aquabacterium(OTU33)and Lysobacter(OTU4).The dominant genera in DL were Sphingomonas(OTU157 and OTU2916),Phenylobacterium(OTU60)and Rhodanobacter(OTU19).The result of cluster thermogram analysis showed that the dominant OTUs in PF and DL were significantly different from those of other land-use types.The dominant bacterial community structure of PC,CR and DL were similar.Redundancy analysis showed that the main soil factors affecting bacterial community structure were pH,soil organic carbon(SOC),total nitrogen(TN),alkali-hydrolysable nitrogen(AN),exchangeable Mg,exchangeable Ca,dissolved organic carbon(DOC)and available phosphorus(AP).(2)Ascomycetes played a dominant role in soil fungi community,accounting for more than75% of all soil fungi.The species diversity and abundance of soil fungi under the five land-use patterns were PF and DL > APF > PC and CR.The dominant classes in PC were Sordarimycetes,Dothideomycetes and Pezizomycetes.The dominant classes in CR were Sordarimycetes,Archaeorhizomycetes and Dothideomycetes.The dominant classes in APF were Sordarimycetes,Dothideomycetes and Eurotimoycetes.The dominant classes in PF were Sordarimycetes,Dothideomycetes and Pezizomycetes.The dominant classes in DL were Sordarimycetes,Dothideomycetes and Agaricomycetes.Among the dominant OTUs,the dominant genera in PC were Westerdykella(OTU12)and 21(Rozellomycota).The dominant genera in CR were OTU50(Montagnulaceae)and 113(Sebacinales Group B).The dominant genera in APF were OTU62(Penicillium)and 26(Sordariales).The dominant genera in PF were OTU1983(Fusarium).Thedominant genera in DL were OTU81(Neurospora),OTU32(Helotiales)and 3104(Mortierella).The result of cluster thermograph analysis showed that there were significant differences in soil fungi community structure among the five land-use types.Redundancy analysis of dominant OTUs revealed that the main ecological factors affecting soil fungi community structure were pH,SOC,AN,TN,DOC,exchangeable Mg and AP.(3)Among the five types of land-use,although the abundance of actinomycetes was high in PC and CR,the diversities in PC and CR were lower than those in PF,DL and APF.Although the dominant classes of soil actinomycetes under five land-use types were Actinobacteria,Thermoleophilia and Acidimicrobiia,the relative abundance of Actinobacteria was significantly different.Among these dominant OTUs,the dominant genera in PC,CR and APF soils were Amycolatopsis(OTU174),Micromonospora(OTU50487 and 47),Nocardioides(OTU8562 and151)and Streptomyces(OTU27888 and 520).The dominant genera in CR soil were Arthrobacter(OTU57),Iamia(OTU361)and Marmoricola(OTU40931).The result of cluster thermogram analysis showed that the aboundance of dominant OTUs in PF and DL affected by human activities was significantly lower than that in PC,PR and APF.Redundancy analysis showed that pH,SOC,AN,TN,AP,DOC and exchangeable Mg were the main ecological factors affecting actinomycete community structure in Huixian wetland.In summary,the changes of vegetation and phy-chemical properties caused by the changes of land-use patterns have significantly changed the community structure and diversity of soil microorganisms in Huixian karst wetland.The main ecological factors affecting soil microbial community structure in Huixian karst wetland were pH,SOC,AN,TN,AP,DOC and exchangeable Mg.