Annonacin accumulation in leaves of <i>Annona muricata</i> L. induced by mycorrhizal colonization

Annona muricata L. is a tropical tree known for its secondary metabolites, particularly acetogenins, which have cytotoxic and antitumor properties. Research has shown that arbuscular mycorrhizal fungi (AMF) symbiosis and drought stress can increase the production of terpenoids, alkaloids, and phenolic compounds in plants. Our objective was to assess whether AMF symbiosis (both species and consortia) and two irrigation regimens enhanced foliar annonacin concentration, the primary acetogenin in A. muricata leaves. Two irrigation levels were used: normal irrigation (NI) and low irrigation (LI). Trees were inoculated with two AMF consortia: Cerro del Metate (CM) and Agua Dulce (AD); and two AMF species: Rhizophagus intraradices and Funneliformis mosseae (FM). Results showed that annonacin concentration was 83% lower in leaves under LI compared to NI. However, AMF symbiosis increased annonacin concentration, especially under LI conditions. Dry leaf weight was higher in mycorrhizal plants under the LI level than in controls. No growth promotion due to AMF symbiosis was observed under NI. In conclusion, AMF symbiosis promotes foliar annonacin concentration in A. muricata leaves in the two irrigation levels. FM treatment promotes higher annonacin concentration in the NI condition, while AD, CM, and FM treatments promotes annonacin concentration in the LI condition.