Transcriptomic analysis reveals distinctive effects of arbuscular mycorrhizal fungi inoculation in halophyte Suaeda salsa under moderate salt condition

With the area of soil salinization increasing, halophytes are being considered and evaluated for their potential to phytoremediate salinized soils. Arbuscular mycorrhizal (AM) fungi can enhance the adaptive capacity for plants in salt environments, including halophytes. However, there are less elaboration in molecular mechanisms about halophytes combined with AM fungi. This study researched the physiological and transcriptomic responses of halophyte Suaeda salsa inoculated with Funneliformis mosseae under 100 mM NaCl. Results revealed AM symbiosis significantly promoted the shoot biomass and shoot Na+ content under moderate salt condition. Mycorrhizal plants have lower the shoot Na+ concentration and shoot soluble sugar concentrations. Transcriptome analysis showed 1316 differentially expressed genes (DEGs) and 424 DEGs were detected in shoot and root compared inoculation with non-inoculation treatment, respectively. The DEGs in shoot were involved in carbohydrate and energy metabolism, photosynthesis, amino acid metabolism, cofactors and vitamins metabolism. Interestingly, the expression of DEGs related to photosynthesis were downregulated in mycorrhizal plants. The DEGs in root were involved in carbohydrate and energy metabolism, photosynthesis, auxin transmembrane transporter. These results revealed that AM fungi regulated the distinctive genes and pathways to promote growth of halophytes. This study suggested the phytoextractive strategy of halophytes combined with AM fungi held significant ecological potential in salinized lithosphere.