School of Life Sciences and Engineering, Southwest University of Science and Technology, Mianyang 621010, China.
School of Environment and Resource, Southwest University of Science and Technology, Mianyang, Sichuan 621010, China; Key Laboratory of Solid Waste Treatment and Resource Recycle, Southwest University of Science and Technology, Mianyang, Sichuan 621010, China.
Sci Total Environ. 2021 Dec 1;798:149222. doi: 10.1016/j.scitotenv.2021.149222. Epub 2021 Jul 22.
Cadmium (Cd) is a major environmental pollutant and one of the most toxic metals in the environment. Arbuscular mycorrhizal fungi (AMF) assisted phytoremediation can be used to remove Cd from polluted soils but the role of AMF, which mediate in Cd accumulation and tolerance, remains poorly understood. Here we inoculated Lolium perenne with two different AMF species (Glomus etunicatum and Glomus mosseae). Mycorrhizal L. perenne and non-mycorrhizal controls were exposed to Cd stress and we tested the effects of AMF mycorrhization on Cd uptake and subsequent tolerance, as well as the underlying mechanisms. Mycorrhizal infection increased root Cd uptake and we observed that net Cd influx was coupled with net Ca influx. The inactivation of Ca transporter channels decreased Cd uptake in non-inoculated roots to a greater extent than in inoculated roots, indicating that AMF activates additional ion transport channels. In consequence, inoculated plants exhibited higher Cd accumulation in both roots and shoots than non-inoculated controls. However, AMF-inoculated plants showed higher chlorophyll concentrations, photosynthesis, and growth under Cd, indicating lower Cd toxicity in AMF-inoculated plants, despite the increase in Cd uptake. We observed that AMF-inoculated favored the isolation of Cd within cell walls and vacuoles, and had higher concentrations of superoxide dismutase activity and glutathione concentration in roots than non-inoculated plants, consequently experiencing less stress upon Cd exposure. Our results highlight the potential and mechanism of AMF for enhancing phytoremediation of L. perenne in heavy metal contaminated environments.
镉 (Cd) 是一种主要的环境污染物，也是环境中最有毒的金属之一。丛枝菌根真菌 (AMF) 辅助的植物修复可用于去除污染土壤中的 Cd，但 AMF 介导 Cd 积累和耐受的作用仍知之甚少。在这里，我们用两种不同的 AMF 物种（厚垣轮枝孢和摩西球囊霉）接种黑麦草。接种和未接种 AMF 的黑麦草暴露在 Cd 胁迫下，我们测试了 AMF 共生对 Cd 吸收和随后的耐受性的影响，以及潜在的机制。菌根感染增加了根 Cd 的吸收，我们观察到净 Cd 流入与净 Ca 流入相关。Ca 转运体通道的失活使未接种根的 Cd 吸收减少的程度大于接种根，表明 AMF 激活了额外的离子转运通道。因此，接种植物在根和地上部分的 Cd 积累均高于未接种对照。然而，尽管 Cd 吸收增加，接种 AMF 的植物在 Cd 下表现出更高的叶绿素浓度、光合作用和生长，表明 AMF 接种植物的 Cd 毒性较低。我们观察到 AMF 接种有利于将 Cd 隔离在细胞壁和液泡内，并且在根中的超氧化物歧化酶活性和谷胱甘肽浓度高于未接种植物，因此在 Cd 暴露下经历的压力较小。我们的结果强调了 AMF 增强重金属污染环境中黑麦草植物修复的潜力和机制。
