Plant and algal cryopreservation: issues in genetic integrity, concepts in cryobionomics and current applications in cryobiology

摘要

Cryopreservation plays a vital role in the long-term in vitro conservation of essential biological material and genetic resources. Cryogenic storage techniques exist for over 100-higher plant species and numerous strains of algae. Often this multi-stage process comprises: pre-growth, cryoprotection, storage in liquid nitrogen, thawing, cell re-growth and plant regeneration. Cryopreservation involves the exposure of in vitro cells or tissues to physical, chemical and physiological stresses causing cryoinjury. Although, the effects of cryoinjury upon the genome are often unknown, any accumulative DNA polymorphisms may not be induced by cryopreservation per se but result from the whole culture-cryoprotection-regeneration process. Successful cryopreservation is often judged by cell and tissue survival and the ability to re-grow or regenerate into complete plants or form new colonies. It is desirable to assess the genetic integrity of recovered germplasm to determine whether it is ‘true-to-type’ following cryopreservation; this can be undertaken at the phenotypic, histological, cytological, biochemical and molecular level. The relevance of these approaches to examine genetic integrity will be discussed along with their limitations. The concept of ‘Cryobionomics’ is presented to re-define the idea of genetic stability regarding the re-introduction of cryopreserved organisms into the environment.