Cryopreservation of transformed and wild-type Arabidopsis and tobacco cell suspension cultures.

We have recently described Arabidopsis cell suspension cultures that can be effectively synchronised. Here, we describe procedures that allow clonal-transformed cell suspension lines to be produced using Agrobacterium-mediated transformation, and an optimised and straightforward procedure for the cryopreservation and recovery of both parental and transformed lines. Frozen cultures show 90% viability and rapid re-growth after recovery. We show that the cryopreservation procedure is equally applicable to the frequently used tobacco bright yellow (BY)2 cell suspension culture, and that cell cycle synchronisation capacity of parental lines is maintained after both transformation and recovery from cryopreservation. The techniques require no specialised equipment, and are suitable for routine laboratory use, greatly facilitating the handling and maintenance of cell cultures and providing security against both contamination and cumulative somaclonal variation. Finally, the ability to store easily large numbers of transformed lines opens the possibility of using Arabidopsis cell suspension cultures for high-throughput analysis.