Characteristics and interactions of soil bacteria, phytocommunity and soil properties in rocky desertification ecosystems of Southwest China

Rocky desertification is a ubiquitous natural landscape in fragile karst areas, which has serious side effects on socioeconomic development and environmental protection. In order to explore in-depth the relationship between soil bacteria, plant communities and soil properties, species composition of herbs and shrubs was investigated, and soil properties were determined. Changes in soil bacterial community structure were detected by high-throughput sequencing of 16S rRNA V3-V4 regions. We found that the species compositions of herbs and shrubs was significantly different among the different rocky desertification grade. The soil bacterial phyla, Proteobacteria, Actinobacteria, Acidobacteria and Chloroflexi, were the most abundant species in the microbial community. Redundancy analysis showed that there were 5, 4, 3 and 3 kinds of soil bacterial phyla in the community and played a key role in the interactions between phytocommunity, soil properties and bacteria from the non-rocky desertification to the intense rocky desertification areas, respectively. The phytocommunity was significantly correlated with environmental factors (pH, Ca, soil enzymes and soil organic carbon). The relative abundance of Verrucomicrobium was low but was significantly correlated with soil properties. The MetaCyc pathway analysis found that the metabolic bacteria had the highest relative abundance in rocky desertification areas. The gradual reduction of the interactions of soil bacteria, plant community composition and multiple soil environmental factors resulted in the gradual degradation of rocky desertification. Our results provided a valuable scientific basis for understanding the interaction between soil bacteria, phytocommunity and soil properties in response to the evolution of rocky desertification, as well as highlighting the impact of microorganisms on different environmental factors.