Phanerochaete chrysosporium reduces heavy metal uptake in rice by affecting rhizosphere microbes and root metabolism

The addition of functional microorganisms is a common approach for remediating farmland contaminated with heavy metals, but the mechanisms underlying their reduction of crop absorption of these metals require further investigation. Here, the effect of adding Phanerochaete chrysosporium (PC) on the accumulation of heavy metals, including antimony (Sb), arsenic (As), chromium (Cr), lead (Pb) and zinc (Zn), in rice was investigated, and the possible mechanisms behind these effects were explored. The results revealed that PC treatment significantly decreased the concentrations of Sb, As, Cr, Pb and Zn in rice grains, while increasing the abundance of four beneficial bacterial genera, including Mycobacterium, Desulfovirga, Methylosarcina, and Ferruginibacter. Ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) analysis showed that adding PC significantly altered the concentrations of root metabolites, including organic acids, choline, and amino acids. The affected metabolic pathways were mainly concentrated in four pathways: (1) histidine metabolism, (2) pyrimidine metabolism, (3) alanine, aspartate, and glutamate metabolism, and (4) glycine, serine, and threonine metabolism. These findings suggest that PC reduces the uptake of heavy metals in rice by altering root metabolism and the composition of the rhizosphere microbiome, providing valuable insights for the remediation of farmland contaminated with heavy metals.