Lan Gao, Shufeng Wang, Hongxia Du, Wancang Zhao, Qiaozhi Mao, Ming Ma, Heinz Rennenberg
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引用次数: 0
Abstract
Background and aims
Rhizobia can enhance legume growth in the presence of heavy metals, making the legume-rhizobium symbiosis promising for heavy metal phytoremediation. This study aimed to elucidate the molecular mechanisms by which rhizobia enhance cadmium (Cd) tolerance of Robinia pseudoacacia.
Methods
We investigated two R. pseudoacacia genotypes with contrasting Cd accumulation capacity: SX (high-accumulating) and HB (low-accumulating). The study examined oxidative stress responses, reactive oxygen species (ROS) scavenging mechanisms, and changes in transcriptome and metabolome profiles following Cd exposure and rhizobium inoculation.
Results
Rhizobium inoculation effectively reduced H2O2 and MDA accumulation in both genotypes, enhancing their antioxidative substances, despite increased shoot Cd accumulation. Furthermore, rhizobium symbiosis promoted the accumulation of amino acids and carbohydrates, providing additional carbon resources and osmo-protective compounds to support Cd stress responses. Transcriptome analysis revealed elevated expression of metal transporter genes (ABC, OPT, HIP, DTX families) in SX shoots, leading to differential Cd accumulation between the genotypes. Under Cd exposure, SX plants exhibited significantly higher levels of flavonoid-related transcripts and metabolites, also antioxidant enzymes and substances compared to HB plants.
Conclusion
Rhizobium inoculation alleviates cadmium toxicity to R. pseudoacacia by mitigating oxidative stress and activating amino acid and carbohydrate metabolism, enhancing the antioxidant defense system and Cd tolerance of R. pseudoacacia. These findings provide new insights into the Cd tolerance mechanisms of the Robinia-rhizobium symbiosis and its utilization for phytoremediation and heavy metal pollution management.
期刊介绍:
Plant and Soil publishes original papers and review articles exploring the interface of plant biology and soil sciences, and that enhance our mechanistic understanding of plant-soil interactions. We focus on the interface of plant biology and soil sciences, and seek those manuscripts with a strong mechanistic component which develop and test hypotheses aimed at understanding underlying mechanisms of plant-soil interactions. Manuscripts can include both fundamental and applied aspects of mineral nutrition, plant water relations, symbiotic and pathogenic plant-microbe interactions, root anatomy and morphology, soil biology, ecology, agrochemistry and agrophysics, as long as they are hypothesis-driven and enhance our mechanistic understanding. Articles including a major molecular or modelling component also fall within the scope of the journal. All contributions appear in the English language, with consistent spelling, using either American or British English.