Physiological and molecular mechanisms of heavy metal accumulation in nonmycorrhizal versus mycorrhizal plants

• Published in: Plant, cell and environment Vol. 42; no. 4; pp. 1087 - 1103
• Main Authors: Shi, Wenguang, Zhang, Yuhong, Chen, Shaoliang, Polle, Andrea, Rennenberg, Heinz, Luo, Zhi‐Bin
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01-04-2019
• Subjects: Accumulation; ATP‐binding cassette transporter; Cell walls; Chelating agents; Detoxification; Fungi; Gene expression; Golgi apparatus; heavy metal ATPase; Heavy metals; Host plants; Metals, Heavy - metabolism; Molecular modelling; Mycorrhizae - metabolism; Mycorrhizae - physiology; Physiology; phytoremediation; Plant roots; Plant Roots - metabolism; Plant Roots - microbiology; Plant Roots - physiology; Plants - metabolism; Plants - microbiology; Sediment pollution; Soil contamination; Soil remediation; transcriptional regulation; Translocation; transporter; Vacuoles; phytoremediation; ATP-binding cassette transporter; transcriptional regulation; heavy metal ATPase; transporter
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1111/pce.13471

Uptake, translocation, detoxification, and sequestration of heavy metals (HMs) are key processes in plants to deal with excess amounts of HM. Under natural conditions, plant roots often establish ecto‐ and/or arbuscular‐mycorrhizae with their fungal partners, thereby altering HM accumulation in host plants. This review considers the progress in understanding the physiological and molecular mechanisms involved in HM accumulation in nonmycorrhizal versus mycorrhizal plants. In nonmycorrhizal plants, HM ions in the cells can be detoxified with the aid of several chelators. Furthermore, HMs can be sequestered in cell walls, vacuoles, and the Golgi apparatus of plants. The uptake and translocation of HMs are mediated by members of ZIPs, NRAMPs, and HMAs, and HM detoxification and sequestration are mainly modulated by members of ABCs and MTPs in nonmycorrhizal plants. Mycorrhizal‐induced changes in HM accumulation in plants are mainly due to HM sequestration by fungal partners and improvements in the nutritional and antioxidative status of host plants. Furthermore, mycorrhizal fungi can trigger the differential expression of genes involved in HM accumulation in both partners. Understanding the molecular mechanisms that underlie HM accumulation in mycorrhizal plants is crucial for the utilization of fungi and their host plants to remediate HM‐contaminated soils.
Heave metal (HM) accumulation is often altered in mycorrhizal plants, but the physiological and molecular mechanisms underlying changes in HM accumulation are elusive. This review summarizes the progress in understanding the physiological and molecular mechanisms involved in HM accumulation in nonmycorrhizal versus mycorrhizal plants. Mycorrhizal‐induced changes in HM accumulation are mainly due to HM sequestration in fungal partners, improvements in the nutritional and antioxidative status of host plants, and fungi‐triggered differential expression of genes involved in HM accumulation in both partners.