Cryobiotechnology of Plants: A Hot Topic Not Only for Gene Banks

Abstract

<jats:p>Agriculture has always been an important part of human evolution. Traditionally, farming is changing and developing with regard to challenges it faces. The major challenges of modern agriculture are food and nutrition safety for the growing world population. Promoting species and genetic diversity in agriculture appears to be an important approach to dealing with those challenges. Gene banks all around the world play a crucial role in preserving plant genetic resources for future crop improvements. The plant germplasm can be preserved in different ways, depending on the species or form of stored plant tissue. This review focuses on a special preservation method—cryopreservation. Cryopreservation is an effective technique for storing living systems at ultra-low temperatures, usually in liquid nitrogen or its vapor phase. This conservation method is crucial for plants that do not produce seeds or that produce non germinating seeds, as well as for plants that propagate vegetatively. Moreover, based on the cryopreservation method, a novel plant biotechnology tool for pathogen eradication called cryotherapy has been developed. The use of liquid nitrogen eliminates plant pathogens such as viruses, phytoplasmas, and bacteria. Our article reviews recent advances in cryo-biotechnologies such as cryopreservation and cryotherapy, with special focus on studies concerning fruit plants.</jats:p>

Grapevine Shoot Tip Cryopreservation and Cryotherapy: Secure Storage of Disease-Free Plants

“…In 1997, Brison et al [ 54 ] reported the first successful eradication of Plum pox virus (PPV) from the infected shoot tips of a Prunus rootstock, using a vitrification method. Since then, shoot tip cryotherapy has been successfully applied to eradicate 37 viruses [ 52 , 153 , 154 , 155 , 156 , 157 , 158 , 159 , 160 , 161 , 162 ], two viroids [ 163 ], two phytoplasmas [ 164 , 165 ], and one bacterium [ 166 ] in 31 plant species. To date, five phloem-limited grape viruses have been eradicated by shoot tip cryotherapy, including Grapevine fanleaf virus (GFLV), Grape virus A (GVA), Grapevine leafroll-associated virus-1,-2,-3 (GLRaV-1,2,3) [ 34 , 51 , 62 , 63 , 64 , 167 ] ( Table 2 ).…”

“…Relative to shoot tip culture or thermotherapy followed by shoot tip culture, shoot tip cryotherapy has the following advantages: cryotherapy yields pathogen-free plants at a high frequency; avoids the time-consuming excision of very small tissues, which requires skillful technicians; does require special equipment in addition to that typically available in a plant tissue culture laboratory. In summary, cryotherapy facilitates the treatment of a large number of samples quickly and simultaneously, reducing costs and making procedures shorter compared to thermotherapy followed by shoot tip culture [ 52 , 54 , 64 , 81 , 152 , 153 , 154 , 155 , 175 , 178 ].…”

Phytotoxicity and Other Adverse Effects on the In Vitro Shoot Cultures Caused by Virus Elimination Treatments: Reasons and Solutions

“…[ 74 ]. Further advantages and disadvantages of the cryotherapy method are very well summarized in many recent reviews [ 76 , 79 , 81 , 82 ].…”

Cryopreservation of Endangered Ornamental Plants and Fruit Crops from Tropical and Subtropical Regions

“…A cryopreserved collection may be used for the establishment of a safety backup for crops propagated clonally. An additional benefit of such backup, compared to the traditional seed bank, is that it can serve hundreds or even thousands of years and does not require regeneration after a few years of storage [ 38 ]. However, despite cryogenic storage having evident strategic merit, the resulting injuries from the cooling and rewarming cycles (affecting the membranes structure, cellular functions, and recovery potential) can cause unacceptable declines in the cell’s viability and regrowth of complete plants, which remains a major limiting factor [ 32 ].…”