Methyl jasmonate elicitation affects expression of genes involved in biosynthesis and turnover of 2-phenylethylamine in maize seedlings

The objective of the study was to assess the influence of methyl jasmonate (MJ) vapors on accumulation of 2-phenylethylamine (PEA), phenylacetic acid (PAA) and 2-phenylethanol (PE) in leaves and roots of maize (Zea mays L. subsp. mays, saccharata group, cv. Złota Karłowa) seedlings. Furthermore, we analyzed the expression patterns of eight genes (ADH1, ADH2, AO2, CAO, PDC1, PDC2, PTA and LOX, encoding alcohol dehydrogenase 1 and 2, primary amine oxidase, aldehyde oxidase 2, phenylalanine decarboxylase 1 and 2, phenylalanine (histidine) transaminase and lipoxygenase, respectively) involved in biosynthesis and turnover of PEA in maize tissues. In addition, the effect of MJ application on fresh biomass and growth of the tested seedlings was recorded. Oneday MJ exposure increased the fresh weight of aerial parts and roots of Z. mays seedlings, whereas the opposite tendency occurred after 4-day of MJ treatment. One-day application of MJ resulted in an increase in the length of roots and its fluctuations in the aerial parts of maize plants, but extended exposure declined the growth of both parts of the seedlings. Methyl jasmonate elicitation caused various changes in the contents of PEA, PAA and PE in the maize seedlings. MJ treatments led to high upregulation of most genes, with the exception of three genes (i.e., ADH1, ADH2 and AO2) whose expression was downregulated after a 4-day exposure.