Pedosphere (5): 783--795, 2025
ISSN 1002-0160/CN 32-1315/P
©2025 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Cadmium detoxification by Stenotrophomonas sp. via cell wall exfoliation and regeneration mediated by mtgA |
Jianming XU1 , Tong WANG1,2, Jiawen ZHANG1, Haoran GUAN1, Zhenmei LÜ3, Xin YAN4, Randy A. DAHLGREN5, Jizheng HE2, Xingmei LIU1 |
1 State Key Laboratory of Soil Pollution Control and Safety, Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China)
2 School of Agriculture, Food and Ecosystem Sciences, Faculty of Science, The University of Melbourne, Parkville VIC 3010 (Australia)
3 College of Life Sciences, Zhejiang University, Hangzhou 310058 (China)
4 College of Life Sciences, Nanjing Agricultural University, Nanjing 210095 (China)
5 Department of Land, Air and Water Resources, University of California, Davis CA 95616 (USA) |
| Corresponding Author:Jianming XU |
| ABSTRACT |
| Understanding bacterial strategies for coping with heavy metal stress is essential for elucidating their resilience in contaminated environments. However, whether cell wall exfoliation contributes to bacterial tolerance under heavy metal stress, such as cadmium (Cd) exposure, remains unclear and requires further investigation. In this study, we reveal a novel self-protective mechanism in Stenotrophomonas sp. H225 isolated from a Cd-contaminated farmland soil, which underwent controlled cell wall exfoliation and regeneration in response to Cd stress up to 200 mg L-1. Transmission electron microscopy and energy-dispersive X-ray spectroscopy analyses revealed that the exfoliated cell wall fragments served as extracellular Cd sinks, thereby reducing intracellular Cd accumulation. Fourier-transform infrared spectroscopy and enzyme-linked immunosorbent assay indicated progressive peptidoglycan (PG) degradation, with exfoliated PG concentration in solution increasing from 148 ng mL-1 at 0 mg L-1 Cd to 240 ng mL-1 at 200 mg L-1 Cd. This degradation was counteracted by the compensatory upregulation of PG biosynthesis genes, with the enrichment ratio reaching up to 0.83, facilitating cell wall reconstruction. Transcriptomic analysis and gene knockout experiments identified mtgA (encoding a monofunctional transglycosylase) as a key determinant in cell wall repair and Cd resistance. To our knowledge, this is the first mechanistic evidence that bacteria can mitigate heavy metal toxicity through dynamic cell wall remodeling involving exfoliation and regeneration. This finding enhances our understanding of microbial survival strategies under environmental stress and highlights potential targets for engineering metal-tolerant strains for bioremediation applications. |
| Key Words: bioremediation,Cd resistance,Cd stress,cell wall remodeling,detoxification strategy,gene knockout,heavy metal,pbpC gene,peptidoglycan |
| Citation: Xu J M, Wang T, Zhang J W, Guan H R, Lü Z M, Yan X, Dahlgren R A, He J Z, Liu X M. 2025. Cadmium detoxification by Stenotrophomonas sp. via cell wall exfoliation and regeneration mediated by mtgA. Pedosphere. 35(5):783-795. |
| |
|
View Full Text
|
|
|
|
