Mechanism of microplastics in the reduction of cadmium toxicity in tomato
Rongchao Yang, Long Cheng, Zihan Li, Yilan Cui, Jiawei Liu, Duo Xu, Sijia Liu, Zhong Lin, Jiugeng Chen, Yueqin Zhang
Abstract
Soil pollution by microplastics (MPs) and cadmium (Cd) poses significant threats to agricultural production, yet their combined toxicity and underlying mechanisms remain poorly understood. Here, we examined the effects of three types of MPs-polyethylene (PE), polyvinyl chloride (PVC) and polypropylene (PP)-with particle sizes of 150 μm and 10 μm, in combination with Cd stress (5 mg/kg) on tomato ( Solanum lycopersicum L.) growth. The results revealed that the combined treatment of MPs effectively alleviated the inhibitory effect of Cd stress. Moreover, Ionome analysis demonstrated that the combined treatment alleviated ionic toxicity by reducing the accumulation of heavy metals (e.g., Al, Pb, Cd, Cr), restoring the uptake of essential elements (e.g., Mg, Ca, Mn), and minimizing the excessive absorption of trace elements (e.g., Mo, Ni) and ultra-trace elements (e.g., Co, Ag, Sn) compared to Cd stress alone. Transcriptome analysis further revealed that combined treatment reprogrammed key pathways, including cell wall synthesis, antioxidant systems, Cd transport, hormone signaling, nitrogen metabolism, and glutathione metabolism, to alleviate Cd toxicity. This study provides novel insights into the interaction between MPs and environmental pollutants, highlighting their role in modulating plant stress responses. • MPs can alleviate the toxicity of Cd, with PVC showing the most effect, PE the least. • Combined stress of MPs and Cd can alleviate the oxidative stress in tomato. • MPs co-exposure can reconstruct the element balance and alleviate element toxicity. • Combined stress of MPs and Cd leads to transcriptional reprogramming in roots. • Combined stress of MPs and Cd reduces the accumulation of Cd and Pb in tomato fruits.