Deciphering the growth pattern and phytohormonal content in Saskatoon berry (Amelanchier alnifolia) in response to in vitro cytokinin application

New Understanding of Meta-Topolin Riboside Metabolism in Micropropagated Woody Plants

Topolin cytokinins have emerged as valuable tools in micropropagation. This study investigates the metabolism of meta-topolin riboside (mTR) in three distinct tree species: Handroanthus guayacan and Tabebuia rosea (Bignoniaceae), and Tectona grandis (Lamiaceae). Employing labeled N15 mTR, we unraveled the complex mechanisms underlying cytokinin homeostasis, identifying N9-glucosylation as the principal deactivation pathway. Our findings demonstrate a capacity in T. rosea and H. guayacan to reposition the hydroxyl group on the cytokinin molecule, a previously unexplored metabolic pathway. Notably, this study reveals remarkable interfamilial and interspecies differences in mTR metabolism, challenging established perspectives on the role of callus tissue in cytokinin storage. These insights not only illuminate the metabolic intricacies of mTR, a cytokinin with interesting applications in plant tissue culture, but also enhances our understanding of cytokinin dynamics in plant systems, thereby enriching the scientific discourse on plant physiology and cytokinin biology.

Effects of Ozone Application on Microbiological Stability and Content of Sugars and Bioactive Compounds in the Fruit of the Saskatoon Berry (Amelanchier alnifolia Nutt.)

Saskatoon berry fruits are a valuable source of micro- and macronutrients, sugars, and compounds with health-promoting properties, the properties of which change during storage. This study presents the effects of applied gaseous ozone at 10 ppm for 15 and 30 min on microbiological stability, sugar content, and bioactive compounds for three cultivars and three clones of Saskatoon berry fruit. The ozonation process had a positive effect on reducing the microbial load of the fruit, which was observed on day 7 of storage for the two variants of ozonation time of 15 and 30 min compared to the control and also on the sugar profile of the “Thiessen” fruit, as well as clones no 5/6 and type H compared to the control sample, which was non-ozonated fruit. In the Saskatoon berry fruits analyzed, 21 polyphenolic compounds were identified, of which four belonged to the anthocyanin group whose main representative was the 3-O-glucoside cyanidin. The ascorbic acid content and antioxidant activity (determined by DPPH· and ABTS⁺· methods) varied according to the cultivar and clone of the Saskatoon berry fruits analyzed and the ozone exposure time.

Effects of Post-Harvest Ozone Treatment on Some Molecular Stability Markers of Amelanchier alnifolia Nutt. Fruit during Cold Storage

Fruits of Amelanchier alnifolia Nutt. ex M. Roem. (Nutt.) are a good source of bioactive compounds and vitamins. Due to the fact that the berries are a soft fruit, they require special procedures to increase their molecular and mechanical stability during cold storage. The study investigated the effects of ozone treatment applied cyclically (every 24 h) on selected chemical and mechanical parameters of saskatoon berries kept in storage. For this purpose, measurements were performed to assess changes in some molecular markers such as antioxidant potential, content of vitamin C, and total polyphenols, as well as microbial stress and maximum destructive force under uniaxial compression of samples. The effectiveness of the storage process was also assessed in relation to the conditions used by determining the proportion of fruit affected by diseases occurring in storage. The findings show that ozone treatment led to increased content of bioactive compounds at the initial stages of storage and resulted in decreased loss of water and bioactive compounds at the later stages. Ultimately, irrespective of the conditions applied during ozone treatment, it was observed that the growth of micro-organisms on the fruit surface was inhibited, and as a result, storage losses during the relevant period were significantly reduced.

Optimization of the micropropagation of elite adult trees of Sequoia sempervirens: forest species of interest in the Basque Country, Spain

Forest trees are renewable sources of timber and other valuable non-timber products. Nowadays, the increase in population and demand for forestry products results in overexploitation of forestry. Therefore, there is an urgent need to produce elite plants with higher productivity under stress derived from climate change to have available to afforestation. For this reason, propagation methods should be improved to be more efficient in terms of quality and productivity. The main species planted in the Basque Country is Pinus radiata; during the last three years, Pinus radiata plantations have suffered a fungus attack affecting mainly needles until the tree's death. This crisis is caused by the combined action of two fungi of the genus Dothistroma and Lecanosticta acicola, whose expansion seems to have been enhanced by weather-related factors, such as humid and hot summers. Although we have evidence of this disease's presence in our mountains since 1942, the disease has had a speedy expansion with an aggressive effect for reasons that are not scientifically known today. For the above, Basque Country forestry sector is looking for alternative species to be used in its plantations. Part of the forestry sector considers that Sequoia sempervirens could be a good choice for plantations. Besides, its high-quality wood and its tolerance to the attack of several pathogens and other diseases derived from climate change are characteristics that could confer some advantage over other forest species. The main goal of this study was to optimize the micropropagation of adult elite trees of Sequoia sempervirens. The effect of 6-benzylaminopurine, meta-Topolin and Kinetin, and 4 types of explant in the multiplication stage were analyzed to carry out this objective. Furthermore, the effect of two types of auxins: 1-naphthalene acetic acid, indole-3-butyric acid, and a mixture of both, were evaluated on the induction of roots and their subsequent effect on the acclimatization process. The best multiplication index was obtained when 4.4 µM 6-benzylaminopurine and apical explants longer than 1.5 cm of length were used. The root induction percentage was 75% in the most responsive genotype analyzed when 4.4 µM 6-benzylaminopurine was used on the induction stage, and 50 µM of 1-naphthalene acetic acid was used for rooting. Finally, after 3 months in the greenhouse, the explants cultured with Kinetin and rooted in a culture medium with indole-3-butyric acid showed the highest acclimatization success (94%).

Applications of Cytokinins in Horticultural Fruit Crops: Trends and Future Prospects

Cytokinins (CKs) are a chemically diverse class of plant growth regulators, exhibiting wide-ranging actions on plant growth and development, hence their exploitation in agriculture for crop improvement and management. Their coordinated regulatory effects and cross-talk interactions with other phytohormones and signaling networks are highly sophisticated, eliciting and controlling varied biological processes at the cellular to organismal levels. In this review, we briefly introduce the mode of action and general molecular biological effects of naturally occurring CKs before highlighting the great variability in the response of fruit crops to CK-based innovations. We present a comprehensive compilation of research linked to the application of CKs in non-model crop species in different phases of fruit production and management. By doing so, it is clear that the effects of CKs on fruit set, development, maturation, and ripening are not necessarily generic, even for cultivars within the same species, illustrating the magnitude of yet unknown intricate biochemical and genetic mechanisms regulating these processes in different fruit crops. Current approaches using genomic-to-metabolomic analysis are providing new insights into the in planta mechanisms of CKs, pinpointing the underlying CK-derived actions that may serve as potential targets for improving crop-specific traits and the development of new solutions for the preharvest and postharvest management of fruit crops. Where information is available, CK molecular biology is discussed in the context of its present and future implications in the applications of CKs to fruits of horticultural significance.

Bioactive Components and Health Benefits of Saskatoon Berry

In response to the recent rise in numbers of diabetes patients, many treatments have been developed; but currently, oral antihyperglycemic agents and insulin are still the main clinical treatments. Since current drugs have limitations and harmful side effects, research in alternative treatments has been sought. This article reviews recent research updates of Saskatoon berries (SB), covering its background information, its main active ingredients, its structure, and its function. Flavonoid compounds in Saskatoon berries, in particular flavanol, anthocyanin, and proanthocyanin, possess anti-inflammatory, antitumor, and antidiabetes impacts. The current review synthesizes the latest research on the health benefits of Saskatoon berry in a variety of domains. With further research, SB has the potential to help treat and prevent diabetes in the future.