Soil Microbial Community Structural And Functional Diversity Of Korean Pine Forest On Changbai Mountain,China

In this study,we took the topsoil(0?5 cm and 5?10 cm)between 699 and 1177 m in Changbai Mountain Korean pine forest,we analyzed the soil microbial community composition and diversity and the carbon metabolic characteristics along elevation gradients by Illumina High-throughput sequencing and Biolog microplate method.The main conclusions are as follows:1)The bacterial 16S rRNA gene was amplified with a set of primers targeting the hypervariable V3-V4 region.We obtained a total 149,519 optimized sequences,with an average length of 437.51 bp.Soil bacterial diversity index increased with increasing elevation from 699 to 937 m and began to decline after reaching 1044 m,showing a humpback curve along elevation.Richness and evenness indices decreased with elevation,all indices varied significantly at different elevations.At phylum and genus levels,although bacterial composition had some differences,the dominant bacterial populations were generally consistent at different elevations.?-diversity analysis indicated that the similarity of bacterial communities decreased with increasing vertical distance among the sample plots.Variation partition analysis showed that geographic distance(mainly elevation gradient)explained 8.42%of the structural variation,soil physicochemical factors explained 70.78%of the structural variation.Obviously,the contribution of contemporary environmental disturbances on maintaining the microbial spatial distribution pattern was greater when compared with historical contingencies.2)We selected the ITS region for PCR amplification and sequencing and obtained a total 186,663 optimized sequences,with an average length of 268.81 bp.Soil fungal diversity indices decreased with increasing elevation from 699 to 937 m and began to rise after reaching 1044 m.Richness and evenness indices decreased with elevation,all indices varied significantly at different elevations.At phylum,class and genus levels,although the dominant fungal populations were generally consistent at different elevations,the abundance of most population differed significantly in an inconsistent manner.(3-diversity analysis indicated that the similarity of fungal communities decreased with increasing vertical distance among the sample plots,and showed a distance-decay relationship.Variation partition analysis showed that geographic distance(mainly elevation gradient)explained 20.53%of the structural variation,soil physicochemical factors explained 69.78%of the structural variation.3)AWCD of 168 h gradually decreased with the increasing altitude,and there were significant differences at different elevations;Shannon,Simpson and McIntosh diversity index also showed same trend with AWCD and three different diversity indices were significantly different along the elevation gradient;The utilization intensity of six categories carbon sources had differences in that the amino acids were the most dominant carbon sources.Principal component analysis(PCA)identified that soil microbial carbon utilization at different altitudes had obvious spatial differentiation,vertical zone difference of soil microbial functional diversity was reflected in the use of carbohydrates,amino acids and carboxylic acids,and the carbohydrates is particularly prominent.In addition,the cluster of the microbial diversity indexs and AWCD values of different altitudes showed that the composition of vegetation will have a significant impact on soil microbial composition and functional activity.