Investigation of bacterial diversity in <i>Cajanus cajan</i> -planted gangue soil via high-throughput sequencing

Abstract

The ecological restoration of coal gangue can be achieved by planting <i>Cajanus cajan</i> (pigeon pea) because of its developed root system. The close relationships soil microorganisms have with plants are crucial for improving soil composition; the soil composition affects nutrient absorption. The microbial composition and function of soil planted with <i>C. cajan</i> in reclaimed land were compared with soil that was not planted with <i>C. cajan</i> (the control). Results showed that the dominant microflora in the soil significantly changed after planting <i>C. cajan</i>. Before planting, the dominant microflora included members of the phyla Sulfobacteria and Acidobacteria. After planting, the dominant microflora contained bacteria from phyla and classes that included <i>Actinobacteria, Acidimicubia, Thermoleophilia</i>, and <i>Anaerolineae</i>. Additionally, there were significant differences in the bacterial composition of each layer in soils planted with <i>C. cajan</i>. Principal component analysis revealed that the interpretation degrees of the results for PC2 and PC3 axes were 10.46% and 3.87%, respectively. The dominant microflora were Vicinamibacterales, <i>Nocardioides</i>, and <i>Arthrobacter</i> in the surface soil; <i>Actinophytocola</i> and <i>Sphingomonas</i> in the deep soil; and <i>Sulfobacillus</i> and <i>Acidimicrobium</i> in the mixed-layer soil. Function prediction analysis using the bioinformatics software package PICRUSt revealed that the abundance of operational taxonomic units corresponding to sigma 54-specific transcriptional regulators, serine threonine protein kinase, and histidine kinase increased by 111.2%, 56.8%, and 47.4%, respectively, after planting <i>C. cajan</i>. This study provides a reference for interactions among microorganisms in reclaimed soils for guiding the development and restoration of waste coal gangue hills.