Effects of chitosan on gene expression of chavicol-O-methyl transferase and phenylpropanoid components of Ocimum basilicum (purple cultivar) under water deficit

Chavicol -O-methyl transferase (CVOMT) is a key enzyme in phenylpropanoid pathway in basil (Ocimum basilicum L.), which is a medicinal and aromatic plant of the Lamiaceae family. In this study, the effect of chitosan elicitor on essential oils yield, phenylpropanoid components and chavicol -O- methyl transfrase gene expression under water deficit was evaluated. The plants under different irrigation regimes were treated with 0.2 and 0.4 g/L chitosan in three stages of growth. Phenylpropanoid compounds were identified by Gas Chromatography and Gas Chromatography/Mass Spectrometry (GC/MS) and the level of gene expression was monitored by Semi quantitative RT-PCR. An analysis of variance indicated that oil yield and CVOMT gene expression and methylchavicol increased under water deficit and chitosan elicitor compared to untreated plants. The changes observed in methylchavicol components were in accordance with the changes of gene expression of chavicol -O-methyl transferase. Thus, chitosan as a biotic elicitor could increase phenylpropanoid components in purple basil by increased gene expression and activity of chavicol -O-methyl transferase.