Phenolic root exudates enhance Avicennia marina tolerance to cadmium under the mediation of functional bacteria in mangrove sediments

Zhanrui Leng; Yueming Wu; Jian Li; Ziying Nie; Hui Jia; Chongling Yan; Hualong Hong; Xinhong Wang; Daolin Du

doi:10.1016/j.marpolbul.2022.114227

Phenolic root exudates enhance Avicennia marina tolerance to cadmium under the mediation of functional bacteria in mangrove sediments

Mar Pollut Bull. 2022 Dec;185(Pt A):114227. doi: 10.1016/j.marpolbul.2022.114227. Epub 2022 Oct 19.

Authors

Zhanrui Leng¹, Yueming Wu¹, Jian Li², Ziying Nie¹, Hui Jia¹, Chongling Yan³, Hualong Hong³, Xinhong Wang³, Daolin Du¹

Affiliations

¹ Institute of Environmental Health and Ecological Security, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China.
² Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, Ministry of Agriculture and Rural Affairs/Tianjin Key Laboratory of Agro-Environment and Agro-Product Safety, Agro-Environment Protection Institution, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China; Institute of Environmental Health and Ecological Security, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, China. Electronic address: jianli@ujs.edu.cn.
³ State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, China.

PMID: 36270055
DOI: 10.1016/j.marpolbul.2022.114227

Abstract

This study was carried out to demonstrate the mechanism of phenolic root exudates affecting microbial-mediated cadmium (Cd) speciation transformation thus enhancing the Avicennia marina tolerance to Cd. A rhizo-box experiment was conducted including eight treatments with four Cd levels (0, 1, 2, and 4 mg Cd kg^-1) and two phenol levels (0, 15 mg kg^-1). The results showed that the addition of phenols increased the pH, reduced the number of iron-reducing bacteria (IRB) and sulfur-oxidizing bacteria (SOB) in the rhizosphere sediments, meanwhile promoted the transformation of Cd to low activity speciation. Furthermore, the sulfate accumulation and synthesis of flavonoid phenols in plants were also enhanced. The results indicated that phenolic root exudates inhibit functional bacteria-mediated Fe and S cycles and promote the immobilization of Cd in the sediments. In conclusion, the mitigation of Cd phytotoxicity induced by phenolic root exudates enhanced the Cd tolerance of A. marina.

Keywords: Avicennia marina; Cadmium; Functional bacteria; Phenolic root exudates; Sediments.

MeSH terms

Avicennia*
Bacteria
Cadmium / toxicity
Exudates and Transudates
Phenols / toxicity
Plant Roots

Substances

Cadmium
Phenols