Pre-treatment with salicylic acid improves plant regeneration after cryopreservation of grapevine (Vitis spp.) by droplet vitrification

Abstract

Despite many reports on regeneration of Vitis after cryopreservation, there is no cryopreserved collection of its germplasm. Some Vitis genotypes are reported to be recalcitrant to cryopreservation. Droplet vitrification, considered to be an emerging generic method of cryopreservation, has been applied only to a limited extent in Vitis. In the present study, we first tested the toxicity of plant vitrification solution in both axillary and apical buds in six diverse Vitis accessions. Droplet vitrification was then applied using 50 % predicted survival time of apical and axillary buds in vitrification solution after pre-treatment of donor plantlets with salicylic acid, a substance known to have a protective role in abiotic stress responses. Results showed that axillary buds are more tolerant of vitrification solution than apical buds and required longer treatment time. Pre-treatment of donor plantlets with 0.1 mM salicylic acid resulted in a significantly higher protection to cryopreserved buds, but serial dehydration in sucrose alone had little effect. Pre-treatment with salicylic acid enabled successful cryopreservation of previously recalcitrant rootstock 41B, albeit at a low regeneration rate. For other genotypes, cryopreservation of 6–11 explants will be sufficient to regenerate at least one plant at 95 % probability. This is the first report of successful cryopreservation of a set of diverse Vitis genotypes by droplet vitrification, and we show that pre-treatment of donor plantlets with salicylic acid is critical for the success. This research will contribute to conservation of Vitis germplasm in a cost-effective way avoiding the risks associated with field-based collections.