Cryopreservation for retaining morphology, genetic integrity, and foreign genes in transgenic plants of Torenia fournieri

Abstract

Torenia fournieri, a popular potted flower crop, is frequently used as a model plant in genetic transformation studies, and transgenic plants expressing various foreign genes have been obtained in this plant. A safe and long-term conservation of the transgenic plants is necessary. In this study, shoot tips of transgenic plants of T. fournieri were successfully cryopreserved by droplet-vitrification. Growth patterns, and morphologies of leaves and flowers were identical between the plantlets recovered from cryopreservation and the in vitro stock cultures (control). No polymorphic bands and no alternations at ploidy level assessed by ISSR and FCM, respectively, were found in the transgenic plantlets recovered from cryopreservation in comparison with the in vitro stock cultures. The transgene Cry 1Ab analyzed by PCR was maintained, and its expression levels measured by qRT-PCR did not change in the cryo-derived transgenic plantlets. Therefore, cryopreservation can be considered a promising strategy for safe and long-term conservation of the transgenes.