Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China.
Forestry Institute of New Technology, Chinese Academy of Forestry, Beijing 100091, China.
Int J Mol Sci. 2021 Oct 28;22(21):11651. doi: 10.3390/ijms222111651.
Cadmium (Cd) pollution occurring in salt-affected soils has become an increasing environmental concern in the world. Fast-growing poplars have been widely utilized for phytoremediation of soil contaminating heavy metals (HMs). However, the woody Cd-hyperaccumulator, × , is relatively salt-sensitive and therefore cannot be directly used to remediate HMs from salt-affected soils. The aim of the present study was to testify whether colonization of × with ectomycorrhizal (EM) fungi, a strategy known to enhance salt tolerance, provides an opportunity for affordable remediation of Cd-polluted saline soils. Ectomycorrhization with strains facilitated Cd enrichment in × upon CdCl exposures (50 μM, 30 min to 24 h). The fungus-stimulated Cd in roots was significantly restricted by inhibitors of plasmalemma H-ATPases and Ca-permeable channels (CaPCs), but stimulated by an activator of plasmalemma H-ATPases. NaCl (100 mM) lowered the transient and steady-state Cd influx in roots and fungal mycelia. Noteworthy, colonization partly reverted the salt suppression of Cd uptake in poplar roots. EM fungus colonization upregulated transcription of plasmalemma H-ATPases (, , ) and annexins (, , ), which might mediate Cd conductance through CaPCs. EM roots retained relatively highly expressed and , thus facilitating Cd enrichment under co-occurring stress of cadmium and salinity. We conclude that ectomycorrhization of woody hyperaccumulator species such as poplar could improve phytoremediation of Cd in salt-affected areas.
镉（Cd）污染在盐渍土壤中日益受到关注。快速生长的杨树被广泛用于修复受重金属（HM）污染的土壤。然而，木质 Cd 超积累植物 × 相对盐敏感，因此不能直接用于修复盐渍土壤中的 HM。本研究旨在验证用外生菌根（EM）真菌定殖 × （已知可提高耐盐性的策略）是否为负担得起的修复 Cd 污染的盐碱土壤提供了机会。用 菌株进行外生菌根定殖可促进 CdCl 暴露（50 μM，30 分钟至 24 小时）后 × 中 Cd 的富集。根中的真菌刺激 Cd 被质膜 H+-ATP 酶和 Ca 通透通道（CaPCs）抑制剂显著限制，但被质膜 H+-ATP 酶激活剂刺激。NaCl（100 mM）降低了根和真菌菌丝体中 Cd 的瞬时和稳态流入。值得注意的是，定殖部分逆转了盐对杨树根 Cd 吸收的抑制作用。EM 菌定殖上调了质膜 H+-ATP 酶（、、）和膜联蛋白（、、）的转录，这可能介导了 Cd 通过 CaPCs 的电导率。EM 根保持相对高表达 和 ，从而有利于 Cd 在镉和盐胁迫共存下的富集。我们得出结论，外生菌根定殖木质超积累植物如杨树可改善盐渍地区 Cd 的植物修复。
