Effects of conditioning factor on anthocyanin production in strawberry suspension cultures

To investigate the effects of the conditioning factor on anthocyanin production in the cultured strawberry, Fragaria ananassa cv Shikinari, cells were cultured in LS medium supplemented with a filtered conditioned broth. Anthocyanin accumulation was greatly enhanced using media conditioned for 5–8 days. This effect was promoted by increased concentrations of the conditioned broth. The amount of anthocyanin produced in a 100% conditioned broth was about eight times higher than in the control broth after 5 days. The substance that promoted anthocyanin accumulation in the conditioned medium was thermostable, because neither cell growth nor anthocyanin accumulation were affected by boiling for 10 min. Anthocyanin production was further enhanced by adding freeze‐dried conditioned broth to freshly prepared LS medium; however, this conditioned broth affected cell growth only in the early phase of culturing. The content of peonidin‐3‐glucoside, a major anthocyanin, increased as the number of days the cell growth proceeded, while that of cyanidin‐3‐glucoside decreased. The contents of these two major anthocyanins were also changed by adding a preculture broth as a conditioning factor.