No abstract

Better knowledge on responses to dehydration stress could help to improve the existing cryopreservation protocols for potato, since plant tissues processed for cryopreservation are often submitted to similar in vitro stress conditions. Cryopreservation (the best method of conservation for vegetatively propagated plants) of potato still needs to be standardized to make it available and to conserve the wide diversity of this crop. In the present work, the response to osmotic stress and chilling temperature was investigated in two potato species, Solanum tuberosum and its relative, frost-tolerant S. commersonii. After 14 days of exposure, different growth parameters, such as shoot length and number of leaves, were measured. Furthermore, differentially abundant proteins were identified after performing 2-fluorescence difference gel electrophoresis (2-DIGE) experiments, and soluble carbohydrates were analyzed by High Performance Anion Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD). The results show different responses in both species depending on the stress treatment. Focusing on the differences in growth parameters during the treatments, Solanum commersonii seems to be more affected than S. tuberosum cv. Désirée. At the molecular level, there are some differences and similarities between the two potato species studied that are dependent on the type of stressor.

No abstract

No abstract

Premise The effective ex situ conservation of exceptional plants, whether in living collections or cryo‐collections, requires more resources than the conservation of other species. Because of their expertise with rare plants, botanical gardens are well positioned to lead this effort, but a well‐developed strategy requires a clear understanding of the resources needed. Methods Grant funding was obtained from the Institute of Museum and Library Services to support a three‐year project on cryobanking, and to provide smaller grants to 10 other botanical gardens for one‐year projects on either (1) seed behavior studies or (2) the development of protocols for in vitro propagation or cryopreservation. Results Nine of the partner gardens worked on 19 species (one was unable to continue due to the COVID‐19 pandemic), while the larger project focused on 14 species. A point system was developed for tasks accomplished, and the average costs per point of the larger and smaller projects were similar. Labor accounted for half the costs. Projects focused on species in the Asteraceae and Orchidaceae had lower costs per point than other species. Discussion Both large and small projects can contribute to a strategy for exceptional plant conservation for similar costs. Prioritizing species with lower costs could help advance the field while allowing time for work on more difficult species to develop.

Cryopreservation combined with in vitro culture offers a safe and cost-effective method to conserve germplasm. Conservation of Persea spp. has been limited to heterozygous somatic embryos that are not true-to-type. A method for shoot-tip cryopreservation is vital to preserve the exact gene pool of interest. For the first time cryopreservation protocols for mature shoot tips of two avocado cultivars (cvs) 'Velvick' and 'Reed', were established. In vitro shoots were subjected to two different optimised pre-treatments; (1) cv 'Velvick'-high sucrose (0.3 M) or (2) cv 'Reed'-low temperature (10 °C) incubation, over a 2-week period prior shoot tip dissection. Two different plant vitrification solutions, plant vitrification solution 2 (PVS2) and vitrification solution L (VSL) were tested at 0 °C for 0, 10, 20, 30 and 40 min. Vitrified shoots were evaluated for survival and regrowth at 2 and 8 weeks after vitrification treatment and either with or without liquid nitrogen exposure. The study revealed that the optimal exposure time for each cultivar varied with the cryoprotectant used. After liquid nitrogen cv 'Velvick' highest regrowth levels were observed with 20 min exposure to either PVS2 or VSL, however, vigorous plants were produced only from VSL treated shoots. In the case of cv 'Reed' highest regrowth levels were observed with 10 min exposure to PVS2 however only morphologically normal plants were recovered from VSL treated shoots. Key messageCryopreservation of avocado shoot tips was successful using PVS2 and VSL with both recording similar recovery rates for 'Velvick' and 'Reed'; although only vigorous and morphologically normal plants were developed from VSL treatments.

Recent development and implementation of crop cryopreservation protocols has increased the capacity to maintain recalcitrant seeded germplasm collections via cryopreserved in vitro material. To preserve the greatest possible plant genetic resources globally for future food security and breeding programs, it is essential to integrate in situ and ex situ conservation methods into a cohesive conservation plan. In vitro storage using tissue culture and cryopreservation techniques offers promising complementary tools that can be used to promote this approach. These techniques can be employed for crops difficult or impossible to maintain in seed banks for long-term conservation. This includes woody perennial plants, recalcitrant seed crops or crops with no seeds at all and vegetatively or clonally propagated crops where seeds are not true-to-type. Many of the world’s most important crops for food, nutrition and livelihoods, are vegetatively propagated or have recalcitrant seeds. This review will look at ex situ conservation, namely field repositories and in vitro storage for some of these economically important crops, focusing on conservation strategies for avocado. To date, cultivar-specific multiplication protocols have been established for maintaining multiple avocado cultivars in tissue culture. Cryopreservation of avocado somatic embryos and somatic embryogenesis have been successful. In addition, a shoot-tip cryopreservation protocol has been developed for cryo-storage and regeneration of true-to-type clonal avocado plants.

No abstract