MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China.
MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China.
Chemosphere. 2024 Oct;366:143464. doi: 10.1016/j.chemosphere.2024.143464. Epub 2024 Oct 3.
Co-contamination of soil by multiple heavy metals is a significant global challenge. An effective strategy to address this issue involves using hyperaccumulators such as Sedum alfredii (S. alfredii). The efficiency of phytoremediation can be improved by supplementing with plant growth-promoting bacteria (PGPB). However, bacteria resources of PGPB resistant to multi-heavy metal contamination are still lacking. This study focused nine different strains of Bacillus and screened for resistance to heavy metals including cadmium (Cd), zinc (Zn), copper (Cu), and lead (Pb). A superior strain, Bacillus subtilis PY79 (B. subtilis), showed tolerance for all tested metals. Inoculation with B. subtilis in the rhizosphere of S. alfredii increased the accumulation of Cd, Zn, Cu, and Pb by 88.02%, 58.99%, 90.22%, and 54.97% in the plant shoots after 30 days respectively. B. subtilis application lowered the pH of the rhizosphere soil, thereby increasing the bioavailability of nutrients and heavy metals. Furthermore, B. subtilis helped S. alfredii recruit PGPB and heavy metal-resistant bacteria such as Edaphobacter, Niastella, and Chitinophaga, enhancing the growth and phytoremediation efficiency. Moreover, inoculation with B. subtilis not only upregulated genes of the ABC, HMA, ZIP, and MTP families involved in the translocation and detoxification of heavy metals but also increased the secretion of antioxidants within the cells. These findings indicate that B. subtilis enhances the tolerance, uptake, and translocation of heavy metals in S. alfredii, offering valuable insights for the phytoremediation of multi-metal-contaminated soils.
土壤中多种重金属的共污染是一个全球性的重大挑战。解决这个问题的一个有效策略是利用超富集植物，如垂盆草（Sedum alfredii）（S. alfredii）。通过添加植物促生菌（PGPB）可以提高植物修复的效率。然而，能够耐受多种重金属污染的 PGPB 细菌资源仍然缺乏。本研究聚焦于九种不同的芽孢杆菌菌株，并筛选出对包括镉（Cd）、锌（Zn）、铜（Cu）和铅（Pb）在内的重金属具有抗性的菌株。一株优势菌株，枯草芽孢杆菌 PY79（Bacillus subtilis）（B. subtilis），对所有测试金属均表现出耐受性。在垂盆草根际接种 B. subtilis 后，30 天后，植物地上部分中 Cd、Zn、Cu 和 Pb 的积累量分别增加了 88.02%、58.99%、90.22%和 54.97%。B. subtilis 的应用降低了根际土壤的 pH 值，从而增加了养分和重金属的生物有效性。此外，B. subtilis 帮助垂盆草招募了 PGPB 和耐重金属的细菌，如 Edaphobacter、Niastella 和 Chitinophaga，从而增强了植物的生长和植物修复效率。此外，接种 B. subtilis 不仅上调了参与重金属转运和解毒的 ABC、HMA、ZIP 和 MTP 家族的基因，还增加了细胞内抗氧化剂的分泌。这些发现表明，B. subtilis 增强了垂盆草对重金属的耐受性、吸收和转运能力，为多金属污染土壤的植物修复提供了有价值的见解。
