l-Phenylalanine supplementation increases the production of phenylalanine ammonia-lyase and methyl cinnamate in the mycelia of Tricholoma matsutake

We investigated changes in the expression of Tmpal1 and Tmpal2, that encode phenylalanine ammonia-lyases (PALs), during the growth of Tricholoma matsutake NBRC 30605 mycelia, and the effect of exogenously added l-phenylalanine (l-Phe), a substrate of PALs, on pal expression and methyl cinnamate production in the mycelia. Expression patterns of Tmpal1 and Tmpal2 differed during mycelial growth. Transcript levels of Tmpal2, PAL activity, and methyl cinnamate content increased markedly in cultures supplemented with 4-6 mM l-Phe. These results indicate that l-Phe supplementation increases PAL activity that is mainly responsible for Tmpal2 expression; consequently, methyl cinnamate is abundantly produced from l-Phe.