Effects of Rhizosphere Microbial Composition on the Growth of Cajanus cajan in Coal Gangue Reclaimed Soil

Abstract

This study aimed to investigate the microbial diversity and functions of Cajanus cajan root systems planted in plateau waste dumps collected in Liupanshui City, Guizhou Province, China. The gangue dump (1,390 m above sea level) in the Guizhou Plateau was covered with soil and planted with YN and JX C. cajan. After 1 year, the C. cajan root system was collected, and high-throughput sequencing was used to examine its bacterial and fungal biodiversity. The unclassified_f_Enterobacteriaceae and Cedecea were the most abundant genera. Venn and heatmap analyses revealed differences in the dominant species Lactococcus and Fusarium in the rhizosphere of C. cajan varieties. In JX and YN, Pseudoarthrobacter is a unique genus of bacteria; in JX, Robillarda is a unique genus of fungi; and in YN, Scytalidium is a unique genus of fungi. Endophytic fungi mainly play the roles of saprotroph, plant pathogen, and endophyte. Among the bacterial properties, L-arabinose isomerase and adenosine triphosphatase were the most abundant in all samples, while chitinase, catalase, and laccase played important roles in photosynthesis and the degradation of lignin, chitin, and chitosan. Our findings may guide the selection of reclamation plants and strategies for the mitigation and restriction of heavy metals in soil.