Root-associated microbiota drive phytoremediation strategies to lead of Sonchus Asper (L.) Hill as revealed by intercropping-induced modifications of the rhizosphere microbiome

Xinyue Mei,Yanqun Zu,Franck Panabières,Fangdong Zhan,Marie Larousse,Martine Da Rocha,Zuran Li,Ying Wang,Yongmei He,Arthur Pere,Linlong Pu

doi:10.1007/s11356-021-17353-1

Abstract

Intercropping or assistant endophytes promote phytoremediation capacities of hyperaccumulators and enhance their tolerance to heavy metal (HM) stress. Findings from a previous study showed that intercropping the hyperaccumulator Sonchus asper (L.) Hill grown in HM-contaminated soils with maize improved the remediating properties and indicated an excluder-to-hyperaccumulator switched mode of action towards lead. In the current study, RNA-Seq analysis was conducted on Sonchus roots grown under intercropping or monoculture systems to explore the molecular events underlying this shift in lead sequestering strategy. The findings showed that intercropping only slightly affects S. asper transcriptome but significantly affects expression of root-associated microbial genomes. Further, intercropping triggers significant reshaping of endophytic communities associated with a ‘root-to-shoot’ transition of lead sequestration and improved phytoremediation capacities of S. asper. These findings indicate that accumulator activities of a weed are partially attributed to the root-associated microbiota, and a complex network of plant–microbe-plant interactions shapes the phytoremediation potential of S. asper. Analysis showed that intercropping may significantly change the structure of root-associated communities resulting in novel remediation properties, thus providing a basis for improving phytoremediation practices to restore contaminated soils.

Highlights

Heavy metal pollution of agricultural soils constitutes one of the most significant environmental pollutions worldwide (Huang et al 2018)
Intercropping with maize caused a significant increase in biomass of Sonchus roots and shoots (23.25% and 42.85%, respectively) compared with the monoculture system (Supplementary Table S1)
Determination of Pb content in roots and shoots of maize showed a significant decrease in the content in shoots and roots, compared with the values obtained under monoculture conditions (Supplementary Figure S2)

Summary

Introduction

Heavy metal pollution of agricultural soils constitutes one of the most significant environmental pollutions worldwide (Huang et al 2018). China has large-scale mineral resources and is among the highest global producers and consumers of metals (Li et al 2014). Huize mining area is a representative area of large-scale lead–zinc deposits in Yunnan province, China (Huang et al, 2003). Metal pollution causes deleterious damage on soil microbial communities and plant growth. Non-essential metals such as lead (Pb) have noxious effects, penetrate plant tissues and affect growth and general metabolism processes such as nutrient uptake and photosynthesis (Gopal and Rizvi 2008; Alves et al 2014). Studies should explore effective methods for elimination of heavy metals from contaminated soils

Methods

Results

Discussion

Conclusion