Impact assessment of beneficial mycorrhizal fungi on phytochemical constituents and nutrient uptake in Gomphrena globosa

Abstract

Arbuscular mycorrhizal fungi are recognized to amend the biosynthesis of metabolites in plants through symbiosis. This relationship provides an opportunity to use host-fungus combinations that maximize secondary metabolite synthesis. Accordingly, the present study aimed to investigate the effects of two different AMFs (Rhizophagus intraradices and Funneliformis mosseae) individually and in combination on the phytochemical composition, antioxidant potential and nutrient uptake in Gomphrena globosa. The findings showed an increased concentration of total phenols (29.10 mg GAE/g DW), flavonoids (25.84 mg QE/g DW), saponins (105.77 mg DE/g DW) and tannins (137.38 mg TAE/g DW) in the methanol leaf extract of G. globosa inoculated with the combined AMF treatment. Moreover, the existence of phenol (benzoic acid) and flavonoid (kaempferol) was also observed using HPTLC analysis. GC-MS study of methanol extract revealed that hexadecanoic acid, methyl ester and 9-octadecenoic acid (Z)-, methyl ester were the major active compounds with the highest area percentage (26.60 % and 23.74 % respectively) found in the combined AMF treatment. Changes in the functional groups due to AMF associations were observed using FTIR analysis, with the maximum level of metabolites reported in the combined treatment, as evidenced by their higher peak intensity. Furthermore, the plants inoculated with both R. intraradices and F. mosseae showed higher concentrations of P (1477.53 mg/kg), K (28872.88 mg/kg), Mg (10137.96 mg/kg), Ca (28723.07 mg/kg), Fe (125.29 mg/kg) and Mo (0.36 mg/kg), as well as antioxidant activity (DPPH IC50 523.09 µg/mL and FRAP 7845.81 µM Fe (II) equivalent) in comparison to control. Overall, it was concluded that co-inoculation of R. intraradices and F. mosseae enhanced the production of secondary metabolites in G. globosa leaves which may be due to the improved mineral nutrition.