Author
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ZHAO, L - Northwest Agricultural University |
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WANG, M-R - Northwest Agricultural University |
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LI, J - Northwest Agricultural University |
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CUI, Z - Northwest Agricultural University |
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Volk, Gayle |
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WANG, QC - Northwest Agricultural University |
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/26/2019 Publication Date: 1/29/2019 Citation: Zhao, L., Wang, M., Li, J., Cui, Z., Volk, G.M., Wang, Q. 2019. Cryobiotechnology: a double-edged sword for obligate plant pathogens. Plant Disease. 103:1058-1067. https://doi.org/10.1094/PDIS-11-18-1989-FE. DOI: https://doi.org/10.1094/PDIS-11-18-1989-FE Interpretive Summary: Pathogen-free stock plants are required as propagation materials in nurseries and healthy materials are needed in germplasm exchange between countries or regions through quarantine programs. In addition, plant gene banks also prefer to maintain pathogen-free germplasm collections. Shoot tip cryotherapy is a novel biotechnology method whereby cryopreservation methods are used to eradicate obligate pathogens from vegetatively propagated plants. Long-term preservation of pathogens are necessary in all types of virus-related basic research and applied applications such as antigen preparation for virus detection by immunology-based methods, production of plant-based vaccines, genetic transformation to produce virus-derived resistant transgenic plants and bionanotechnology to produce nano drugs. Obligate plant pathogens such as viruses and viroids are intracellular parasites that colonize only in living tissues. Therefore, their long-term preservation is difficult. Cryotreatments cannot completely eradicate the obligate pathogens that infect meristematic cells and a certain proportions of plants recovered from cryotreatments are still pathogen-infected. Furthermore, cryotreatments often fail to eradicate the obligate pathogens that infect meristematic cells. Cryopreservation can be used for the long-term cryopreservation of the obligate plant pathogens. Thus, cryobiotechnology functions as a double-edged sword for plant pathogen eradication and cryopreservation. This review provides updated a synthesis of updated advances in cryopreservation techniques for eradication and cryopreservation of obligate plant pathogens. Technical Abstract: Cryopreservation techniques have traditionally been used to conserve plant genetic resources in genebanks. Shoot tip cryopreservation methods treat 1 mm plant shoot tips with cryoprotectants prior to liquid nitrogen exposure and plants can be regenerated from the shoot tips upon warming. Optimized cryopreservation techniques can be used for cryotherapy, whereby shoot tips are treated with liquid nitrogen and obligate plant pathogens are eradicated. This is particularly useful for removing viruses and viroids from nursery propagation materials and from imported plants in quarantine programs. In some cases, pathogens are not eradicated from plant tissues when shoot tips are cryopreserved and the pathogens are actually preserved along with the plant tissue. This review discusses how cryopreservation technologies, or "cryobiotechnology", can both conserve and eradicate obligate plant pathogens in shoot tips. |