|PENCE, VALERIE - Cincinnati Zoo & Botanical Garden|
|PHILPOT, MEGAN - Cincinnati Zoo & Botanical Garden|
|BALLESTEROS, DANIEL - Royal Botanic Garden Sydney|
|CULLEY, THERESA - University Of Cincinnati|
|VANHOVE, ANNE-CATHERINE - Cincinnati Zoo & Botanical Garden|
|REED, BARBARA - Retired ARS Employee|
|PRITCHARD, HUGH - Royal Botanic Garden Sydney|
|DIXON, KINGSLEY - Curtin University|
Submitted to: Biological Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/18/2019
Publication Date: 10/1/2020
Citation: Pence, V., Philpot, M., Ballesteros, D., Culley, T., Vanhove, A., Reed, B., Walters, C.T., Pritchard, H., Dixon, K. 2020. Cryobiotechnologies: Tools for expanding long-term ex situ conservation to all plant species. Biological Conservation. https://doi.org/10.1016/j.biocon.2020.108736.
Interpretive Summary: There are 1750 plant genebanks in the world today, and most of these store seeds using prescribed conditions for drying and freezer (-20C) storage. However, there are a large number of wild plants that cannot be stored using these conventional methods because the seeds have unusual storage behavior or seeds aren't available or produced. Cryogenic storage methods using liquid nitrogen are required and examples of successful cryopreservation - in which germplasm has survived for decades -- are increasingly demonstrated. Numerous plant parts can be cryopreserved, and the requirement for in vitro culture to supply source materials or regenerate thawed samples has ushered a new discipline called cryobiotechnology.
Technical Abstract: There is a growing need for increased efforts to conserve plant biodiversity. The genetic diversity of many crops is well represented in ex situ seed banks and the number of seed collections of wild species is growing. However, approaches beyond seed banking are needed for exceptional species, or those that cannot survive long-term in conventional seed banking. Many such species are found in tropical areas of high species diversity that are particularly under threat. Cryobiotechnology, including cryopreservation (storage in liquid nitrogen) and in vitro technologies, offers the potential for conserving exceptional species, securing germplasm for future restoration of species that are declining in the wild. Cryopreservation has been demonstrated as a safe and effective method for conserving species of short-lived seeds, zygotic embryos, dormant buds, spores, pollen, shoot tips, somatic embryos, gametophytes, and algae and there are a growing number of studies indicating that viability can be maintained over at least 2-3 decades. Instituting the use of cryopreservation, supported by in vitro technologies, on a broad scale is of immediate importance to stem the loss of the diversity of exceptional species, and this can be accomplished by building on the expertise and infrastructure that has developed over the past 30 years. Here we review the application of cryobiotechnologies to a variety of plant tissues in order to highlight their potential and to call for a global effort to broaden ex situ conservation to all plant species.