Enhancing Stress Tolerance in Cadmium and Zinc Contaminated Soil: The Role of AMF and Metal-Tolerant Pseudomonas fluorescens

Description

Heavy metal (HM) contamination in agricultural soils significantly threatens soil health and plant productivity. This study investigates cadmium (Cd) and zinc (Zn) stress impact on tomato plants (Solanum lycopersicum) while exploring the mitigation potential of microbial biostimulants (MBs)—arbuscular mycorrhizal fungi (AMF) and Pseudomonas fluorescens So_08 (PGPR)— employing multi-omics approaches. Specifically, the investigation delves deeply into soil-plant communication mechanisms mediated by root exudates and rhizosphere microbial communities. Root exudate profiling revealed distinct metabolic changes under HM stress, which compromised soil-plant interactions. Under Cd stress, key classes of metabolites, including phenylpropanoids, lipids, and isoprenoids, show reduced secretion. These metabolites play crucial roles in antioxidative defense, suggesting a shift in resource allocation mechanisms. Moreover, Cd negatively impacted rhizosphere fungal populations. Conversely, Zn stress prompted an increased exudation of lipids, including sphingolipids and sterols, reflecting an adaptive strategy to preserve membrane integrity and functionality. This stress also influenced rhizobacterial community structures. The MB application mitigated HM-induced stress by enhancing specialized metabolite syntheses, including cinnamic acids, terpenoids, and flavonoids, which promoted crop resilience. MBs also reshaped microbial diversity, fostering beneficial species like Portibacter spp., Alkalitalea saponilacus under Cd stress, and stimulating rhizobacteria like Aggregatilinea spp. under Zn stress. Multi-omics data integration combined with network analysis highlighted key features associated with improved nutrient availability and reduced HM toxicity under MB treatments, including metabolites and microbial taxa linked to sulfur cycling, nitrogen metabolism, and iron reduction pathways. These findings demonstrate that MBs can modulate plant metabolic responses and restore rhizosphere microbial communities under Cd and Zn stress, with PGPR showing broader metabolomic recovery effects and AMF influencing specific metabolite pathways. This study provides new insights into plant-microbe interactions in HM-contaminated environments, supporting the potential application of biostimulants for sustainable soil remediation and plant health improvement.

Institutions

Categories

Additional Metadata for UCSC Datasets

Licence