The effect of phenylalanine on biosynthesis of protoberberine alkaloids in the cell culture of low meadow-rue.

摘要

The addition of 7 mM phenylalanine to the nutrient medium for low meadow-rue (Thalictrum minus) cell culture on the 7th or 8th day increased berberine secretion into the medium by 2-fold. The content of phenolic compounds increased in the cells and medium. Exogenous phenylalanine activated phenylalanine ammonia-lyase (PAL) by 35% and inactivated tyrosine ammonia-lyase [phenylalanine ammonia-lyase] (TAL) by 20%. When the crude extract was separated on DEAE-Sephacel column, 2 proteins were isolated. One of them exhibited both PAL and TAL activities, whereas the other protein showed only PAL activity. This activity disappeared when the cell was cultured for more than 20 days and when phenylalanine was applied at a concentration that reduced alkaloid biosynthesis. Phenylalanine addition to the medium also increased the content of protein in both cells and culture medium. The proportion of low-molecular proteins in the medium increased. The antimicrobial activity of the medium was determined by berberine and, to a lesser degree, by palmatine. The protein fraction also demonstrated antimicrobial activity. An improved antimicrobial activity after phenylalanine application resulted from alkaloid and protein accumulation. One of the mechanisms of phenylalanine action was the control of alkaloid biosynthesis with the involvement of the enzyme system of the early steps of the phenylpropanoid pathway, which, in its turn, is one of the stages in stress-induced plant response to pathogen action..