Effect of arbuscular mycorrhizal fungi on the accumulation of secondary metabolites in roots and reproductive organs of Solanum nigrum, Digitaria sanguinalis and Ipomoea purpurea

Background The application of arbuscular mycorrhizal fungi (AMF) can induce the synthesis and accumulation of secondary metabolites in the tissues of host plants, thus impacting their allelopathic potential. Materials and methods The objective of this study was to determine the effect of three AMF species (Rhizoglomus intraradices, Funneliformis mosseae, Rhizoglomus fasciculatum) on photosynthetic pigments and secondary metabolites content in roots and reproductive organs ofIpomoea purpureaL.,Digitaria sanguinalisL., andSolanum nigrumL. as a problematic weed species. Results Among compared weeds, the roots ofD. sanguinalisassociated with AMF accumulated the highest level of phenols. Higher content of flavonoids was obtained in roots ofS. nigrum (7.46 mg g−1FW)following colonization withR. intraradices.Berries ofS. nigruminoculated withR. intraradiceshad a higher concentration of terpenoids (21.45 mg 100 mL−1of extract) than reproductive organs ofD. sanguinalisandI. purpurea.Colonization withR. intraradicesimproved total phenolics in seeds ofD. sanguinaliscompared to the reproductive organs of other weeds. These compounds released from seeds help defend against pathogen infection, consequently increasing seed production. In addition, phenylalanine ammonia lyase enzyme activity in leaves ofD. sanguinaliscolonized byR. fasciculatumandF. mosseaewas 55% and 67%, respectively, higher thanI. purpureaplants, grown in the same condition. Conclusions Results suggest that AMF can play a crucial role in enhancing of secondary metabolites in these three weeds, thereby improving their allelopathic potential and competitive ability. Graphic Abstract