Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
Sci Total Environ. 2024 May 15;925:171770. doi: 10.1016/j.scitotenv.2024.171770. Epub 2024 Mar 17.
The exploration of microbial resources to reduce Pb accumulation in rice attracted great attention. In this study, we found Penicillium oxalicum SL2, a Pb-tolerant strain with good capability of dissolving phosphorus and stabilizing Pb in soil, was able to colonize on the root surface of rice seedlings without additional carbon sources, and promoted the secretion of metabolites related to amino acid metabolism, organic acid metabolism, signal transduction and other pathways in rhizosphere exudates, in which the secretion of oxalate increased by 47.7 %. However, P. oxalicum SL2 increased Fe(II) proportion and Fe availability on the root surface, resulting in iron plaque content decrease. Moreover, by converting root surface Pb from Pb-Fe state to PbCO and Pb-P compounds, P. oxalicum SL2 increased Pb intercept capacity of iron plaque by 118.0 %. Furthermore, P. oxalicum SL2 regulated element distribution on the root surface, and reduced the relative content of Pb on the maturation zone of root tip, which was conducive to reducing Pb uptake by apoplastic pathway and the risk of Pb accumulation in root system. Our findings further revealed the interaction between P. oxalicum SL2 and rice root, providing a theoretical basis for the development and application of microbial agents in Pb-contaminated farmland.
探索微生物资源以减少水稻中 Pb 的积累引起了极大关注。在本研究中，我们发现耐 Pb 的青霉 SL2 菌株具有良好的溶解磷和稳定土壤中 Pb 的能力，无需额外的碳源即可定殖在水稻幼苗的根表面，并促进了与氨基酸代谢、有机酸代谢、信号转导等途径相关的代谢物在根际分泌物中的分泌，其中草酸的分泌增加了 47.7%。然而，青霉 SL2 增加了根表面 Fe(II)的比例和 Fe 的可用性，导致铁斑含量减少。此外，通过将根表面的 Pb 从 Pb-Fe 状态转化为 PbCO 和 Pb-P 化合物，青霉 SL2 增加了铁斑对 Pb 的截留能力 118.0%。此外，青霉 SL2 调节了根表面的元素分布，降低了根尖成熟区 Pb 的相对含量，这有利于减少质外体途径中 Pb 的吸收和根系中 Pb 积累的风险。我们的发现进一步揭示了青霉 SL2 与水稻根之间的相互作用，为开发和应用微生物剂来修复 Pb 污染农田提供了理论依据。
