Effect of cadmium stress on the bacterial community in the rhizosphere of mulberry (Morus alba L.)

• Published in: Brazilian journal of microbiology Vol. 54; no. 3; pp. 2297 - 2305
• Main Authors: Hu, Guiping, Cao, Hongmei, Ye, Chuan, Wang, Feng
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-09-2023; Springer Nature B.V
• Subjects: Abundance; Acidobacteria; Bacteria; Bacteria - genetics; Biomedical and Life Sciences; Cadmium; CD3 antigen; CD5 antigen; Comparative analysis; Diversity indices; Food Microbiology; Heavy metals; Humans; Life Sciences; Medical Microbiology; Microbial Ecology; Microbial Genetics and Genomics; Microbiology; Microbiomes; Microorganisms; Morus; Morus alba; Mycology; Phytoremediation; Pollution levels; Principal components analysis; Redundancy; Rhizosphere; Soil and Agricultural Microbiology - Research Paper; Soil contamination; Soil pollution; Soil remediation; Soils; Cd; Bacteria community; Stress response; Mulberry rhizosphere
• ISSN: 1517-8382; 1678-4405; 1678-4405
• DOI: 10.1007/s42770-023-01090-3

Mulberry has a good tolerance to cadmium (Cd) and is considered a candidate plant for phytoremediation. The rhizosphere microbial community plays an important role in phytoremediation. Nevertheless, little information on the rhizosphere microbial community mechanisms in mulberry during the phytoremediation of Cd-contaminated soil is available. In this study, the remediation efficiency of mulberry in pots subjected to three simulated Cd pollution levels and their rhizosphere bacterial communities during the remediation process were analyzed. “Yuesang 11” was used as the test mulberry variety, and three simulated Cd pollution levels were set by adding three concentrations of Cd (Cd5, 5 mg kg
−1
; Cd3, 3 mg kg
−1
; Cd2, 2 mg kg
−1
). The results showed that the elimination rates of Cd in the rhizosphere soil were 81.7%, 85.3%, and 57.9% under the stress of the Cd2, Cd3, and Cd5 conditions, respectively. Meanwhile, 3,082,583 high-quality sequence reads and 976 operational taxonomic units were successfully obtained from the mulberry rhizosphere soil by high-throughput absolute quantification sequencing and further assigned to 11 bacterial phyla and 26 families. Of these, decreased abundances of 19 bacteria at the family level and increased abundances of seven bacteria under Cd stress were revealed by comparative analysis. Based on the alpha diversity indices (Chaol, Shannon and Simpson) and principal component analysis, the rhizosphere bacterial diversity of the Cd5 condition was significantly decreased, but that of the Cd2 and Cd3 conditions was not different from that of soil without Cd (CK). Likewise, redundancy analysis showed that the abundances of
Acidobacteria
Gp2,
Acidobacteri
a Gp13, and
Sphingobacteria
were significantly positively associated with the elimination rates of Cd. This study suggested that the mulberry rhizosphere contains a relatively stable bacterial community consisting of diverse Cd-resistant bacteria, providing a scientific basis for remediating heavy-metal polluted soils using mulberry.