Biobanking of vegetable genetic resources by in vitro conservation and cryopreservation

Today, application of in vitro culture by means of slow growth storage of shoot cultures and cryopreservation of organs, tissues and cells in liquid nitrogen presents a remarkable strategic tool to support medium- and long-term conservation of plant genetic resources. Over the last 30 years, considerable progresses have been made in the development of both methods that are currently considered as ex situ conservation strategies, complementary to traditional seed banks and in-field clonal collections. Efficient protocols were developed for the conservation of a large number of crops, including strategically-important vegetables, such as garlic, artichoke, asparagus, cassava, Jerusalem artichoke, mint, potato, sweet potato, chicory, taro, thyme and yam. As a consequence, more than 45,000 accessions of vegetable crops are maintained in 22 genetic resources conservation centers (biobanks), located in 16 countries and 6 continents (Europe, Asia, Africa, Oceania, North and South America). Approximately 4/5 of these accessions are maintained in vitro by means of slow growth storage of shoot cultures, but cryopreservation is also constantly growing, with almost 8300 vegetable accessions being stored in liquid nitrogen at − 196 °C

Somatic embryogenesis in Abies nebrodensis, an endangered Sicilian fir

Somatic embryogenesis, as a promising biotechnological tool for many conifer trees, has never been applied for the Abies nebrodensis species. Although all the encouraging results previously obtained by the EU LIFE (European LIFE program) funded projects in over ten years, the critically endangered Sicilian fr remains alarmingly close to extinction. In this study, we reported the first protocol of somatic embryogenesis obtained from mature zygotic embryos of the Abies nebrodensis. Seeds from Abies adult trees with specifc identifcation numbers (IN) were collected and full seeds were identifed by X-ray. Diferent experiments were carried out for callus initiation, from both zygotic immature and mature embryos, testing diferent culture media. The immature embryos did not give embryogenic tissue (ET). Embryogenic callus (EC) was successfully induced from mature embryos with variable frequencies (0–40%). Schenk and Hilderbrandt (SH) was the most suitable initiation medium where the obtained callus initiation rate reached up to 40% for IN7 (frst experiment). 6-benzylaminopurine (BAP) showed to be essential to induce EC (second experiment). IN8 presented the highest callus initiation rate (40%) among all tested donor trees, whereas IN13 recorded the lowest rate with 4% (third experiment). ET maturation from each singular embryo of IN7, IN8, IN10 and IN21 was successfully achieved in SH medium containing 37,83 µM abscisic acid (ABA), 8% of polyethylene glycol (PEG-4000) and 4% maltose. The encapsulation technology was assessed on the obtained ET and its proliferation was observed after encapsulation

Large-scale plant production of lycium barbarum l. By liquid culture in temporary immersion system and possible application to the synthesis of bioactive substance

Goji (Lycium barbarum L.) has recognized nutritive and antioxidant properties and many products are commercialized for health in food market. Besides its food use, goji has been the subject of more than 2000 years of traditional Chinese medicine, using berries, root bark, and leaves. Here, the potential of the liquid culture in temporary immersion system (TIS) by using the bioreactor Plantform™ was tested for the large-scale production of high-quality goji shoots and the subsequent production of total phenols and flavonoids. The three tested immersion cycles differently influenced the shoot quality in terms of proliferation and hyperhydricity. The best immersion cycle (time and frequency) was proven to have the shortest daily immersion time (6 min every 24 h) which ensured good levels of relative growth and multiplication rate, very limited onset of hyperydricity, and the longest shoots, promoting direct rooting after only 30 days of culture. In comparison with the semisolid culture, the TIS culture resulted in an increase of the total phenolic content (TPC) and in a lower value of the total flavonoid content (TFC). However, considering the higher quantity of biomass produced in the Plantform™ bioreactor, the difference in terms of TFC productivity between semisolid medium and TIS liquid culture was proven to be statistically equivalent

Shoot-tips vitrification protocol for red chicory (Cichorium intybus L.) lines

Shoot tips from in vitro stock plants of red chicory ‘Rosso di Chioggia’ line were cryopreserved by one-step vitrification. After two days of cold-hardening on hormone-free MS medium and loading for 30 min in a mixture of 2 M glycerol and 0.4 M sucrose at 25°C, shoot tips were dehydrated with PVS2 vitrification solution at 0°C for 60 min and plunged directly into liquid nitrogen. The post-thaw survival of shoot tips was achieved 79% when was cultured on recovery medium containing 0.5 mM BA. Observed regrowth, after six weeks of culture in the same medium composition, was 100%. Rooted cryopreserved microshoots showed good quality when transferred to the greenhouse. Preliminary results proved that the genetic fidelity of the cryopreserved line was maintained. The same vitrification protocol was then applied to three other red chicory lines, ‘Rosso di Treviso precoce’, ‘Rosso di Treviso tardivo’ and ‘Castelfranco’. A simple and effective protocol for the cryopreservation of red chicory shoot tips has been successfully developed as a result of this study

Separable spatio-temporal kriging for fast virtual sensing

Environmental monitoring is a task that requires to surrogate system-wide information with limited sensor readings. Under the proximity principle, an environmental monitoring system can be based on the virtual sensing logic and then rely on distance-based prediction methods, such as $k$-nearest-neighbors, inverse distance weighted regression and spatio-temporal kriging. The last one is cumbersome with large datasets, but we show that a suitable separability assumption reduces its computational cost to an extent broader than considered insofar. Only spatial interpolation needs to be performed in a centralized way, while forecasting can be delegated to each sensor. This simplification is mostly related to the fact that two separate models are involved, one in time and one in the space domain. Any of the two models can be replaced without re-estimating the other under a composite likelihood approach. Moreover, the use of convenient spatial and temporal models eases up computation. We show that this perspective on kriging allows to perform virtual sensing even in the case of tall datasets.Comment: Submitted to Applied Stochastic Models in Business and Industry on September 30, 202

Biochar successfully replaces activated charcoal for in vitro culture of two white poplar clones reducing ethylene concentration

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The Evolution of Invasiveness in Garden Ants

It is unclear why some species become successful invaders whilst others fail, and whether invasive success depends on pre-adaptations already present in the native range or on characters evolving de-novo after introduction. Ants are among the worst invasive pests, with Lasius neglectus and its rapid spread through Europe and Asia as the most recent example of a pest ant that may become a global problem. Here, we present the first integrated study on behavior, morphology, population genetics, chemical recognition and parasite load of L. neglectus and its non-invasive sister species L. turcicus. We find that L. neglectus expresses the same supercolonial syndrome as other invasive ants, a social system that is characterized by mating without dispersal and large networks of cooperating nests rather than smaller mutually hostile colonies. We conclude that the invasive success of L. neglectus relies on a combination of parasite-release following introduction and pre-adaptations in mating system, body-size, queen number and recognition efficiency that evolved long before introduction. Our results challenge the notion that supercolonial organization is an inevitable consequence of low genetic variation for chemical recognition cues in small invasive founder populations. We infer that low variation and limited volatility in cuticular hydrocarbon profiles already existed in the native range in combination with low dispersal and a highly viscous population structure. Human transport to relatively disturbed urban areas thus became the decisive factor to induce parasite release, a well established general promoter of invasiveness in non-social animals and plants, but understudied in invasive social insects