C-2013: Cryopreservation of Passiflora pohlii Mast Nodal Segments and Assessment of Genetic Stability of Recovered Plants

Abstract

Passiflora pohlii Mast. (Passifloraceae) is a wild species native to Brazil, with a potential agronomic interest due to its tolerance to soil-borne pathogens that cause damage to the passion fruit culture. Because this species occurs in impacted regions, the goal of this study was the development of an efficient cryopreservation strategy for nodal segments excised from axenic plants using vitrification-based methods. The genetic stability of the recovered plants was also evaluated by RAPD and ISSR. In the encapsulation–vitrification protocol, precultured explants on medium with high sucrose concentrations (0.3–0.7 M) were encapsulated in calcium alginate beads, followed by incubation in liquid 1/2MSM medium with 0.75 M sucrose for 24 h. After this, beads were exposed to PVS2 or PVS3 for different periods before immersion into LN. In the vitrification protocol, precultured explants were incubated in the cryoprotectant solutions and stored in LN using the same conditions adopted for encapsulation–vitrification. Frozen materials were rewarmed at 40 °C and transferred to the recovery medium (MSM supplemented with 30.8 μ M BA). Explants were kept in the dark for 30 or 60 days before transfer to the presence of light. Although plant recovery was achieved using both vitrification-based protocols, higher recovery rates were obtained with the vitrification technique, when explants were incubated in the dark. RAPD and ISSR analyses indicated that shoots derived from cryopreserved explants were genetically stable at the genomic regions tested. These results show that cryopreservation of nodal segments through the vitrification technique can be used for long-term storage of P. pohlii germplasm.