Schematic representation of the model proposed to explain cadmium stress alleviation in shoots of M. truncatula plants upon AM symbiosis. on the basis of the proteins and parameters identified in the current study as differentially accumulated in response to G. irregulare inoculation and/or metal treatment. Plant components identified in this work and explicit for this model are indicated in grey-shaded boxes. Red-shaded up- and green-shaded down-headed arrows indicate significant (n = 3, p < 0.05) increased and decreased component abundance in Cd-treated mycorrhizal plants relative to those only inoculated with G. irregulare, respectively. Green or red-shaded boxes indicate generally known mechanisms of regulation. Inferred metabolic pathways and intermediates are shown in non-shaded bold and non-bold letters, respectively. AM, arbuscular mycorrhizal; ASC, ascorbate; APX, ascorbate peroxidase; Cd2+, cadmium ion; DHA, dehydroascorbate; DHAR, dehydroascorbate reductase; Fd, ferredoxin; FNR, ferredoxin-NADP+ reductase, GAPDH, glyceraldehyde-3-phosphate dehydrogenase; GSH, reduced glutathione; GSSH, glutathione disulfide; GST, glutathione S-transferase; LHC, light harvesting complex; MDA, monodehydroascorbate; MDAR, monodehydroascorbate reductase; NA, nicotianamine; NAS, nicotianamine synthase; P, phosphate; PC, plastocyanin; PDI, protein disulfide isomerase; PFK, phosphofructokinase; PGK, phosphoglyceraldehyde kinase; PQ, plastoquinone; PR-2, class 2 pathogenesis-related protein; PSI, photosystem I, PSII, photosystem II; ROS, reactive oxygen species; SAM, S-adenosylmethionine; TCA, tricarboxylic acid; TrsS2, thioredoxin disulfide; Trx(SH)2, reduced thioredoxin; UDPG, uridine diphosphoglucose;*, modified from ; ╬ indicates molecules having antioxidant properties; ☼indicates molecules having metal chelation properties.