Roles Of Cryopreservation In Conservation Of Plant Genetic Resources - Presentation

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Roles of Cryopreservation in Conservation of Plant Genetic Resources

Introduction

Various scientific explorations have led to identification of major geographic centres of cultivated plants and their wild relatives. Unfortunately, as more new variants of cultivars are produced, the natural repositories of germplasm, especially the wild strain faces the dilemma of extinction due to the neglected behaviour of human and deliberate destruction for human development. Cryopreservation have been adopted in order to preserve the reservoirs of genetic diversity to overcome the threat.

What is Cryopreservation? Cryopreservation is the storage of living cells at ultra-low temperatures, usually in liquid nitrogen. Cryopreservation is a four-step process: adding cryoprotective agents to cells before cooling cooling the cells to the low temperature at which the cells are stored warming the cells removing the cryoprotective agents from the cells after thawing

What is Cryopreservation? variety of plant material can be used, including cells in tissue culture, pollen, seeds or parts of seeds, embryos, tissues from the early stages of development of mosses and ferns, buds, twigs, and meristematic (growing point) tissue.

Preserving the Genetic Resources of Plants

Preserving the Genetic Resources of Plants

Cryopreservation approach has been especially useful when applied to plant germplasm that has proved recalcitrant to traditional cryopreservation methods using controlled rate freezing. The manipulation of water content status to promote vitrification has been used to greatest effect for tropical crop plant germplasm, recalcitrant forest tree seeds and certain tropical fruit crops that produce recalcitrant seeds or are clonally propagated. Cryopreservation protocols have been set up for more than 40 tropical species.

Maintain Biosynthetic Properties of Plants

Cryopreservation is a sound alternative for the long-term conservation of plant genetic resources, since under these conditions, biochemical and most physical processes are completely arrested; and plant material can be stored for unlimited periods. Cryopreservation was known able to conserve specific features of tissues that can be lost during normal in-vitro maintenance. Cryopreservation, recently, proved to be extremely useful for the safe long-term storage of plant tissues with specific characteristics, such as medicinal- and alkaloid-producing cell lines, hairy root cultures, and genetically transformed and transformation-competent culture lines. Examples includes Papaver somniferum , Chrysanthemum cinerariaefolium , rice, maize, coffee, banana, etc.

Increase Efficiency and Expanding Storage Capacity

Conservation of cryopreserved germplasm in designated, international culture collections provides an important means of coordinating the management of all categories of crop genetic resources. A major factor affecting the increased use of cryopreservation in plant conservation has been the concomitant improvement of routine tissue culture techniques and the development of simple cryoprotection methods that enhance recovery. Moreover, cryopreservation found to greatly facilitate the international exchange of germplasm. Indeed, the size of the samples is drastically reduced and they can be shipped in sterile conditions.

Reducing Maintenance Cost and Space

Cryopreservation of plant cell, tissues, and embryos as frozen germplasm has reduced the cost and demand for plant land space, reduced unwanted genetic drift, as well as reduces the vertical and horizontal transmission of pathogens, and therefore reduced the necessity for importation quarantines. Effective cost reduction should be up to 25% when using cryopreservation rather than traditional field clonal banks. The IPGC (International Populous Genome Consortium) encourages the development of cryogenic storage methods for archiving and distributing germplasm.

Minimizing Risk of Contamination, Disease, Mutation

In addition to economic consideration, the risk of losing clones is very low in cryopreserved clone banks than in soil established clone banks. This based on the consideration of external/outside epidemic disease attacks, storms, or other natural calamities. These events can partially or completely destroy a clonal archive, while characteristics of cryobanks make it easier to protect them efficiently. Cryopreservation has standard, aseptic system: free from fungi, bacteria, viruses (after thermotherapy and indexation) and insect pests; and at the same time: production of pathogen-free stocks genetic erosion reduced to zero under optimal storage conditions.

Multi-option Conservation and Use of Gene Banks

The potential of plant cryopreservation can only be fully exploited by effective technology transfer to gene banks and culture collections. Cryopreservation is now an accessible conservation option for a wide range of users and it has the potential to support both small- and large-scale laboratories and conservation centres. Cryopreservation does not aim to replace the traditional in situ and ex situ approaches to tree germplasm preservation. Rather, it should be regarded as complementary, in order to develop a multi-option modus operandi for the conservation and use of gene banks, to provide a real guarantee against accidental loss of plant genetic resources. Principally, one of the most important applications of plant cryopreservation is, therefore, in a support of crop plant, forestry, and agroforestry breeding program.

Genetic Integrity of Plants from Cryopreservation

Cryopreservation results in the exposure of tissues to physical, chemical, and physiological stresses which all can cause cryoinjury. Moreover, some threats to genetic stability arise from particular reactions (free radical formation, molecular damage due to ionizing radiation) that can still occur at the temperature of –196°C, as well as from the common practice of using DMSO as cryoprotectant at concentrations up to 10%. Although the number of reports studying these aspects in detail is still limited, the fact that, up to now, no clear evidence of morphological, cytological or genetic alterations due to cryopreservation has been produced is promising. Fundamentally, it is necessary to evaluate the genetic stability of material recovered from cryopreserved samples before this technique is routinely used for long-term conservation of plant germplasm.

Conclusion

Although the concept of cryopreservation is inherently simple, the challenge posed by the diversity of plant tissues that can be preserved and our limited knowledge on cryogenics make this technique highly complex. The main drawback for a wider application of plant cryopreservation is the unavailability of efficient cryopreservation protocols for many plant species. Research should move in the direction of simplifying and standardizing the procedures as much as possible, in order to make the technology available to a wide range of public institutions and private companies.

Conclusion

Preserving the Genetic Resources of Plants Maintain Biosynthetic Properties of Plants Increase Efficiency and Expanding Storage Capacity Reducing Maintenance Cost and Space Minimizing Risk of Contamination, Disease, Mutation Multi-option Conservation and Use of Gene Banks

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