Physiological mechanism of the response to Cr(VI) in the aerobic denitrifying ectomycorrhizal fungus Pisolithus sp.1

Liang Shi; Xuan Zhao; Kecheng Zhong; Qiyuan Jia; Zhenguo Shen; Jianwen Zou; Yahua Chen

doi:10.1016/j.jhazmat.2022.128318

Physiological mechanism of the response to Cr(VI) in the aerobic denitrifying ectomycorrhizal fungus Pisolithus sp.1

J Hazard Mater. 2022 May 5:429:128318. doi: 10.1016/j.jhazmat.2022.128318. Epub 2022 Jan 20.

Authors

Liang Shi¹, Xuan Zhao¹, Kecheng Zhong¹, Qiyuan Jia¹, Zhenguo Shen¹, Jianwen Zou², Yahua Chen³

Affiliations

¹ College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
² College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
³ College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; National Joint Local Engineering Research Center for Rural Land Resources Use and Consolidation, Nanjing Agricultural University, Nanjing 210095, China; The Collaborated Lab. of Plant Molecular Ecology Between College of Life Sciences of Nanjing Agricultural University and Asian Natural Environmental Science Center of the University of Tokyo, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: yahuachen@njau.edu.cn.

PMID: 35086038
DOI: 10.1016/j.jhazmat.2022.128318

Abstract

Pisolithus sp. 1 (P sp. 1) is an ectomycorrhizal fungus (EMF) with a strong Cr(VI) tolerance and reduction ability. The noninvasive microttest technique (NMT), real-time quantitative PCR (qRT-PCR), and the three-dimensional excitation-emission matrix (3D-EEM) were used to deeply explore the physiological mechanism of the P sp. 1 response to Cr(VI) and investigate the relationship between Cr(VI) reduction and denitrification in P sp. Cr(VI) induced the strongest elevations in nitrate reductase (NR) activity and NO production in the mycelia after treatment with Cr(VI) for 48 h under aerobic conditions. The NR inhibitor tungstate significantly inhibited Cr(VI) reduction, proton efflux and the expression of the NR gene (niaD) and NiR gene (niiA). In addition, NO was generated via NR-regulated denitrification. Combined treatments with Cr(VI) and the NO scavenger carboxy-PTIO (cPTIO) significantly increased O₂^-, H₂O₂ and MDA contents and reduced SDH, CAT, GSH, GR and GSNOR activity. Therefore, the NR-driven aerobic denitrifying process requires protons, and the generated NO reduces the oxidative stress effect of Cr(VI) on mycelia by reducing ROS accumulation and lipid peroxidation, enhancing mycelial and CAT activity, and promoting GSH recycling and regeneration. Psp.1 can also secrete humic acid-like and protein-like substances to combine with Cr(III) in a culture system.

Keywords: Cr(VI); Denitrification; NO; Nitrate reductase; Pisolithus sp.1.

Publication types

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

MeSH terms

Basidiomycota* / metabolism
Chromium / metabolism
Hydrogen Peroxide / metabolism
Mycorrhizae* / metabolism
Oxidation-Reduction

Substances

Chromium
chromium hexavalent ion
Hydrogen Peroxide