Rhizospheric Lactobacillus spp. contribute to the high Cd-accumulating characteristics of Phytolacca spp. in acidic Cd-contaminated soil

Xiong Li; Boqun Li; Yuanyuan Liu; Jianchu Xu

doi:10.1016/j.envres.2023.117270

Rhizospheric Lactobacillus spp. contribute to the high Cd-accumulating characteristics of Phytolacca spp. in acidic Cd-contaminated soil

Environ Res. 2023 Dec 1;238(Pt 2):117270. doi: 10.1016/j.envres.2023.117270. Epub 2023 Sep 29.

Authors

Xiong Li¹, Boqun Li², Yuanyuan Liu³, Jianchu Xu⁴

Affiliations

¹ Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; Honghe Center for Mountain Futures, Kunming Institute of Botany, Chinese Academy of Sciences, Honghe, 654400, China. Electronic address: lixiong@mail.kib.ac.cn.
² Science and Technology Information Center, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
³ Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
⁴ Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; Honghe Center for Mountain Futures, Kunming Institute of Botany, Chinese Academy of Sciences, Honghe, 654400, China.

PMID: 37776944
DOI: 10.1016/j.envres.2023.117270

Abstract

Screening high Cd-accumulating plants and understanding the interactions between plants, rhizospheric microbes and Cd are important in developing microbe-assisted phytoremediation techniques for Cd-contaminated soils. In this study, the Cd tolerance and accumulation characteristics of Phytolacca americana L., P. icosandra L. and P. polyandra Batalin growing in acidic Cd-contaminated soil were compared to evaluate their phytoremediation potential. According to Cd concentrations (root: 8.26-37.09 mg kg^-1, shoot: 2.80-9.26 mg kg^-1), bioconcentration factors (BCFs) and translocation factors (TFs), the three Phytolacca species exhibited high Cd-accumulation capacities, ranked in the following order: P. icosandra (root BCF: 1.25, shoot BCF: 0.31, TF: 0.25) > P. polyandra (root BCF: 0.68, shoot BCF: 0.26, TF: 0.44) > P. americana (root BCF: 0.28, shoot BCF: 0.09, TF: 0.38). Phytolacca icosandra and P. polyandra can thus be considered as two new Cd accumulators for phytoremediation. Soil pH, available Cd (ACd) concentration and certain bacterial taxa (e.g. Lactobacillus, Helicobacter, Alistipes, Desulfovibrio and Mucispirillum) were differentially altered in the rhizospheres of the three Phytolacca species in comparison to unplanted soil. Correlation analysis showed that there were significant interactions between rhizospheric ACd concentration, pH and Lactobacillus bacteria (L. murinus, L. gasseri and L. reuteri), which affected Cd uptake by Phytolacca plants. The mono- and co-inoculation of L. murinus strain D51883, L. gasseri strain D51533 and L. reuteri strain D24591 in the rhizosphere of P. icosandra altered the rhizospheric pH and ACd concentrations, in addition to increasing the shoot Cd contents by 31.9%-44.6%. These results suggest that recruitment of rhizospheric Lactobacillus spp. by Phytolacca plants contributes to their high Cd-accumulating characteristics. This study provides novel insights into understanding the interactions between plants, rhizobacteria and heavy metals.

Keywords: Environmental pollution; Heavy metals; Lactobacillus; Phytoextraction; Phytolacca; Rhizobacteria.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Bacteria
Biodegradation, Environmental
Cadmium / analysis
Lactobacillus
Metals, Heavy* / analysis
Phytolacca*
Plants
Soil / chemistry
Soil Pollutants* / analysis

Substances

Cadmium
Soil Pollutants
Metals, Heavy
Soil