Plant cryopreservation: implementation and outreach

Genebanks conserve vast collections of plant genetic resources that are maintained as seeds, plant tissue cultures, and actively growing plants in the field and greenhouse. These collections must be securely backed-up at secondary locations to minimize the risk of loss due to equipment failure, natural disasters, pests/diseases, and climate change. Cryopreservation technologies have been developed to place dormant buds and shoot tips into liquid nitrogen, which minimizes the long-term costs of safety duplication. Although there are many published methods in the literature, it can be challenging to directly use those methods for routine processing of genebank materials. This may be because of the variation in lab-to-lab operations or the source and genotypes of the specific taxa that are processed. We have recently tested previously established shoot tip cryopreservation methods for Fragaria (strawberry), Mentha (mint), and Actinidia (kiwifruit) to determine if they could be used with no or minimal modification in our program at the National Laboratory for Genetic Resources Preservation in Fort Collins, Colorado. We found that the Fragaria and Mentha methods could be easily adopted and that the Actinidia method was suitable with minor modifications. We have developed online educational resources at a new website (https://grin-u.org ) including a freely available eBook titled “Training in Plant Genetic Resources: Cryopreservation of Clonal Propagules” (https://colostate.pressbooks.pub/clonalcryopreservation/ ) that demonstrates the shoot tip cryopreservation process for Fragaria, Mentha, and other horticultural crops. The advantage of this educational platform is that text, images, videos, and downloadable protocols are packaged in an online resource that can be viewed by students, technical staff, as well as researchers.