Cadmium-tolerant Bacillus cereus 2-7 alleviates the phytotoxicity of cadmium exposure in banana plantlets

Lu Zhang; Yulin Hu; Yufeng Chen; Dengfeng Qi; Bingyu Cai; Yankun Zhao; Zhuoyang Li; Yong Wang; Zongyu Nie; Jianghui Xie; Wei Wang

doi:10.1016/j.scitotenv.2023.166645

Cadmium-tolerant Bacillus cereus 2-7 alleviates the phytotoxicity of cadmium exposure in banana plantlets

Sci Total Environ. 2023 Dec 10:903:166645. doi: 10.1016/j.scitotenv.2023.166645. Epub 2023 Aug 30.

Authors

Lu Zhang¹, Yulin Hu², Yufeng Chen³, Dengfeng Qi³, Bingyu Cai³, Yankun Zhao³, Zhuoyang Li³, Yong Wang⁴, Zongyu Nie⁴, Jianghui Xie³, Wei Wang⁵

Affiliations

¹ National Key Laboratory of Tropical Crop Breeding, Hainan Institute for Tropical Agricultural Resources, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, Hainan 571101, China; Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou, Hainan 571158, China.
² South Subtropical Crops Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, Guangzhou 524091, China.
³ National Key Laboratory of Tropical Crop Breeding, Hainan Institute for Tropical Agricultural Resources, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, Hainan 571101, China.
⁴ Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou, Hainan 571158, China.
⁵ National Key Laboratory of Tropical Crop Breeding, Hainan Institute for Tropical Agricultural Resources, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, Hainan 571101, China. Electronic address: wangweisys@ahau.edu.cn.

PMID: 37657542
DOI: 10.1016/j.scitotenv.2023.166645

Abstract

Bananas are the world's important fruit and staple crop in the developing countries. Cadmium (Cd) contamination in soils results in the decrease of crop yield and food safety. Bioremediation is an environmental-friendly and effective measure using Cd-tolerant plant growth promoting rhizobacteria (PGPR). In our study, a Cd-resistant PGPR Bacillus cereus 2-7 was isolated and identified from a discarded gold mine. It could produce multiple plant growth promoting biomolecules such as siderophores, indole-3-acetic acid (IAA), 1-aminocyclopropane-1-carboxylate (ACC)-deaminase and phosphatase. The extracellular accumulation was a main manner of Cd removal. Surplus Cd induced the expression of Cd resistance/transport genes of B. cereus 2-7 to maintain the intracellular Cd homeostasis. The pot experiment showed that Cd contents decreased by 50.31 % in soil, 45.43 % in roots, 56.42 % in stems and 79.69 % in leaves after the strain 2-7 inoculation for 40 d. Bacterial inoculation alleviated the Cd-induced oxidative stress to banana plantlets, supporting by the increase of chlorophyll contents, plant height and total protein contents. The Cd remediation mechanism revealed that B. cereus 2-7 could remodel the rhizosphere bacterial community structure and improve soil enzyme activities to enhance the immobilization of Cd. Our study provides a Cd-bioremediation strategy using Cd-resistant PGPR in tropical and subtropical area.

Keywords: Bacillus sp.; Bacterial community; Bioremediation; Cadmium; Plant growth promotion; Soil enzyme activities.