Transcriptome analysis for exploring the molecular mechanism of AMF on the adaption of salt-tolerance grass under combined stress of cadmium and salt

Phytoremediation may difficult performance for Cadmium (Cd) contaminated saline soil because common plants hardly survive in the combine toxic effects of Cd and salt. Arbuscular mycorrhizae fungi (AMF) can help plants endure diverse abiotic stresses. Salt-tolerance grasses can generally grow under salt conditions, and certain of them can also tolerate heavy metal stress. However, few studies have focused on the roles of AMF in salt-tolerance grasses under Cd contaminated saline soils, and little information have elaborate the molecular mechanisms of the symbiosis. A greenhouse pot experiment was conducted to investigate the effects of AMF (Funneliformis mosseae) on growth, nutrient and ion uptake, ion homeostasis, and transport of Cd and Na+ in three salt-tolerance grasses (Leymus chinensis, Puccinellia distans and Astragalus adsurgens) under Cd contaminated saline soil. Further, we investigated the regulation of genes by AMF symbiosis in A. adsurgens under Cd contaminated saline soil by transcriptome analysis. AMF promoted nutrient uptake and reduced concentration and transport of Cd and salt so that ion toxicity was alleviated in A. adsurgens under Cd contaminated saline soils. The mitigation may result in the downregulation of genes related to cell wall and antioxidant enzymes. The study suggests the potentiality of salt-tolerance grasses associated with AMF to rehabilitate the heavy metal contaminated saline ecosystems.