[Structure and Metabolic Function Characteristics of Soil Bacterial Communities under Different Vegetation Types in Arid Region]

Abstract

The aim of this study was to explore the effects of different vegetation types on soil bacterial community structure and metabolic function in an oasis-desert ecotone and provide scientific theoretical basis for species allocation and management of vegetation reconstruction in arid desert ecosystem. Nitraria sphaerocarpa Maxim and Calligonum mongolicum Turcz are the main natural vegetation, Haloxylon ammodendron Bunge, and Hedysarum scoparium Fisch are the primary artificial vegetation, and Ha-Cm are the main mixed community in an oasis-desert ecotone in northwest China. Understanding soil microbial community structure and function under typical vegetation types is crucial for accurate management and sustainable use of desert vegetation. We used high-throughput sequencing technology to explore the effects of different vegetation types on the structure, diversity, and metabolic pathways of soil bacteria and to investigate the key factors driving the change of soil bacterial community structure. The results showed that the growth of artificial vegetation and natural vegetation significantly increased the richness and diversity of the soil bacterial community, but no significant difference was observed. Metagenomic analysis showed that the same dominant bacterial phyla existed in all soils, but the proportions were different. Actinobacteriota, Proteobacteria, and Chloroflexi were the absolute dominant bacterial phyla, accounting for 65.12%-78.68% of the total bacteria. Principal co-ordinates analysis showed significant differences in soil bacterial community structure in the planted forest but similarities in the natural forest. The metabolic pathways of soil bacteria in different vegetation communities were similar. Soil organic carbon （SOC）, available phosphorus （AP）, and pH were important abiotic factors affecting the functional structure of bacteria. The findings are helpful for furthering the understanding of plant-soil interaction in ecologically fragile deserts.

Keywords: arid region; metabolic function; oasis-desert ecotone; soil bacterial structure; vegetation type.