Assay of phenolic compounds and essential oils in mycorrhizal mint genotypes

In this study، total phenolic compounds and essential oils content of six mint genotypes (Bojnoord، Esfahan، Kashan، Kermanshah، Mybod and Yazd) were investigated following inoculation with two arbuscular mycorrhizal fungi (AMF) strains (Glomus etunicatum and G. mosseae). Moreover، phenylalanine ammonia-lyase (PAL) enzyme activity and trichome (main sites of essential oil synthesis) number of fresh leaves were studied. The results revealed that mint plants inoculated with AMF (Glomus sp.) made higher phenolic and essential oils content than nonmycorrhizal mint plants. However، the response was found to be dependent on the genotype. Also، it was found that there was a positive correlation between total phenolic accumulation and PAL enzyme activity in leaves of inoculated plants with AMF. Increased oil yield was associated with significant biomass content and the number of glandular trichome. Result of this study showed that inducing biosynthesis pathway of essential oils and phenolic compound was possible through infection by mycorrhizal fungi، and that the different genotypes of mint showed different potentials in responding to this induction.