Rhizobium inoculation enhances copper tolerance by affecting copper uptake and regulating the ascorbate-glutathione cycle and phytochelatin biosynthesis-related gene expression in Medicago sativa seedlings

Juan Chen, Yu Qing Liu, Xiao Wu Yan, Ge Hong Wei, Jianhua ZHANG, Lin Chuan Fang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

Despite numerous reports that legume-rhizobium symbiosis alleviates Cu stress in plants, the possible roles of legume-rhizobium symbiosis and the regulatory mechanisms in counteracting Cu toxicity remain unclear. Here, Sinorhizobium meliloti CCNWSX0020 was used for analyzing the effects of rhizobium inoculation on plant growth in Medicago sativa seedlings under Cu stress. Our results showed that rhizobium inoculation alleviated Cu-induced growth inhibition, and increased nitrogen concentration in M. sativa seedlings. Moreover, the total amount of Cu uptake in inoculated plants was significantly increased compared with non-inoculated plants, and the increase in the roots was much higher than that in the shoots, thus decreasing the transfer coefficient and promoting Cu phytostabilization. Cu stress induced lipid peroxidation and reactive oxygen species production, but rhizobium inoculation reduced these components’ accumulation through altering antioxidant enzyme activities and regulating ascorbate-glutathione cycles. Furthermore, legume-rhizobium symbiosis regulated the gene expression involved in antioxidant responses, phytochelatin (PC) biosynthesis, and metallothionein biosynthesis in M. sativa seedlings under Cu stress. Our results demonstrate that rhizobium inoculation enhanced Cu tolerance by affecting Cu uptake, regulating antioxidant enzyme activities and the ascorbate-glutathione cycle, and influencing PC biosynthesis-related gene expression in M. sativa. The results provide an efficient strategy for phytoremediation of Cu-contaminated soils.

Original languageEnglish
Pages (from-to)312-323
Number of pages12
JournalEcotoxicology and Environmental Safety
Volume162
DOIs
Publication statusPublished - 30 Oct 2018

Scopus Subject Areas

  • Pollution
  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis

User-Defined Keywords

  • Antioxidant enzymes
  • Ascorbate-glutathione cycle
  • Copper stress
  • Legume-rhizobium
  • Phytoremediation

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