Cryopreservation of Chrysanthemum cinerariaefolium Vis. cells and its impact on their pyrethrin biosynthesis ability.

An efficient protocol for cryogenic storage of high-pyrethrin-producing cell lines of Chrysanthemum cinerariaefolium is described. Optimal survival (92%) was obtained with cells precultured in 1/2 Murashige and Skoog nutrient medium containing 180 g ⋅ l-1 sucrose for 30 days, then incubated in the same medium in the presence of 5% DMSO for 1 h in an ice bath, cooled slowly to -20°C and immersed for 30 min in liquid nitrogen. After cryopreservation, the cells conserved the same growth pattern, but displayed different biochemical properties. The subculture derived from the thawed cells was characterized by a lower chlorophyll content and a higher pyrethrin biosynthesis ability.