Cryopreservation of Arachis Hypogaea L. Varieties, from the INIAP-Ecuador Germplasm Bank

The peanut (Arachis hypogaea L.) is recognized as one of the most important legume crops globally for its use in human food; it is widely distributed and cultivated in tropical and subtropical regions. The purpose of this study was to evaluate the cryopreservation of five peanut varieties conserved in the INIAP Germplasm Bank, testing cryopreservation methods, evaluating the germination percentage of whole seeds and embryonic shoots. Subsequently, two quantitative variables, shoot length and root, were evaluated. The average germination percentage of varieties and treatments was higher when embryonic axes were isolated with 99.31% than 86.06% seeds. The best germination percentage of the five varieties for seeds and embryonic shoots was obtained by the Peruvian variety with 88.13% and 92.50%. The best treatments by variety for the germination of whole seeds and embryonic axes were obtained by the treatment (desiccation and NL) for whole seeds (GS2) with 95.42% and embryonic axes with 92.83%. Ageing and cryopreservation treatments positively affected germination and seedling vigor in whole seeds and embryonic axes. The two quantitative variables, shoot and root length showed variability between the five varieties; significant differences were observed between the four treatments evaluated for whole seeds and embryonic axes. The three treatments for whole seeds (GS1, GS2 GS3) and the non-cryopreserved control treatment (GSC), as well as the treatments for embryonic axes (GEA1, GEA2 GEA3) and the non-cryopreserved control treatment (GEAC), obtained good survival. They germinate whole seeds and embryonic axes with sprout development (aerial part) and root formation. With the most effective treatments for whole seeds (GS2) and embryonic axes (GEA2), the cryopreservation of the national peanut collection of the INIAP Germplasm Bank could be started.

NAD(P)H Drives the Ascorbate–Glutathione Cycle and Abundance of Catalase in Developing Beech Seeds Differently in Embryonic Axes and Cotyledons

European beech is an important component of European lowland forests in terms of ecology, and produces irregular seeds categorized as intermediate due to their limited longevity. Removal of the excess of reactive oxygen species is crucial for redox homeostasis in growing plant tissues. Hydrogen peroxide (H2O2) is detoxified via the plant-specific ascorbate-glutathione cycle, and enzymatically, mainly by catalase (CAT). The reduced and oxidized (redox) forms of ascorbate (AsA, DHA) and glutathione (GSH, GSSG) decreased during maturation as the content of redox forms of nicotinamide adenine dinucleotide (NADH, NAD+) phosphate (NADPH, NADP+), cofactors of ascorbate–glutathione enzymes, declined and limited this cycle. The degree of oxidation of glutathione peaked at approximately 80%, at the exact time when the NADP content was the lowest and the NADPH/NADP+ ratio reached the highest values. The glutathione pool was reflected in changes in the NADP pool, both in embryonic axes (R2 = 0.61) and in cotyledons (R2 = 0.98). A large excess of NADPH was reported in embryonic axes, whereas cotyledons displayed more unified levels of NADP redox forms. As a result, anabolic redox charge and reducing power were higher in embryonic axes. CAT was recognized as two proteins, and the abundance of the 55 kDa protein was correlated with all redox forms of ascorbate, glutathione, NAD, and NADP, whereas the 37 kDa protein was oppositely regulated in embryonic axes and cotyledons. Here, we discuss the role of NAD(P) in the regulation of the ascorbate–glutathione cycle, catalase, and seed longevity concerning a putative role of NAD(P)H as a redox biomarker involved in predefining seed quality, because NAD(P)H-derived redox homeostasis was found to be better controlled in embryonic axes than cotyledons.

Sustainable and efficient protocols for in vitro germination and antioxidants production from seeds of the endangered species Araucaria araucana

Background The Pehuén or Monkey puzzle tree (Araucaria araucana) is an evergreen coniferous tree, which has been historically used for social, medicinal, and nutritional purposes. We have recently showed the value of A. araucana seeds as a rich source of micronutrients and antioxidants. This endemic species present in a reduced area in Argentina and Chile is endangered because of the low germination rate and the overexploitation of its edible seeds. Thus, the massive extraction of its seeds is ecologically non-viable resulting in limited availability of its active metabolites. However, biotechnological approaches are attractive strategies of production of valuable metabolites and healthy specimens of endangered plants. The aim of this work was to develop a protocol for in vitro production of antioxidants derived from A. araucana seeds and to obtain healthy plants by optimized seed germination. Results Calli of Pehuén seeds were induced in Murashige and Skoog medium with different combinations of auxins and cytokinins, in light and dark conditions. Callus from embryonic axes developed in medium with 1 mg/l α-naphthaleneacetic acid and 1.5 mg/l 6-benzylaminopurine in light conditions had efficient biomass production, antioxidant activity, high phenolic, and flavonoid content and no cytotoxicity on mammalian cells. Additionally, 100 % germination was obtained in vitro and healthy plants were acclimatized to non-sterile conditions. Conclusion In conclusion, in vitro culture of A. araucana could provide new and sustainable options for production of its valuable metabolites with possible therapeutic and nutritional uses. Also, optimized plant germination and acclimatization of endangered species can contribute to the preservation of pristine environments.

Hecw controls oogenesis and neuronal homeostasis by promoting the liquid state of ribonucleoprotein particles

Specialised ribonucleoprotein (RNP) granules are a hallmark of polarized cells, like neurons and germ cells. Among their main functions is the spatial and temporal modulation of the activity of specific mRNA transcripts that allow specification of primary embryonic axes. While RNPs composition and role are well established, their regulation is poorly defined. Here, we demonstrate that Hecw, a newly identified Drosophila ubiquitin ligase, is a key modulator of RNPs in oogenesis and neurons. Hecw depletion leads to the formation of enlarged granules that transition from a liquid to a gel-like state. Loss of Hecw activity results in defective oogenesis, premature aging and climbing defects associated with neuronal loss. At the molecular level, reduced ubiquitination of the Fmrp impairs its translational repressor activity, resulting in altered Orb expression in nurse cells and Profilin in neurons.

Melatonin Application Modifies Antioxidant Defense and Induces Endoreplication in Maize Seeds Exposed to Chilling Stress

The aim of the study was to demonstrate the biostimulating effect of exogenous melatonin (MEL) applied to seeds via hydroconditioning. It was indicated that only well-chosen application technique and MEL dose guarantees success concerning seed germination and young seedlings growth under stress conditions. For maize seed, 50 μM of MEL appeared to be the optimal dose. It improved seed germination and embryonic axes growth especially during chilling stress (5 °C/14 days) and during regeneration after its subsided. Unfortunately, MEL overdosing lowered IAA level in dry seeds and could disrupt the ROS-dependent signal transduction pathways. Very effective antioxidant MEL action was confirmed by low level of protein oxidative damage and smaller quantity of lipid oxidation products in embryonic axes isolated from seeds pre-treated with MEL and then exposed to cold. The stimulatory effects of MEL on antioxidant enzymes: SOD, APX and GSH-PX and on GST-a detoxifying enzyme, was also demonstrated. It was indicated for the first time, that MEL induced defence strategies against stress at the cytological level, as appearing endoreplication in embryonic axes cells even in the seeds germinating under optimal conditions (preventive action), but very intensively in those germinating under chilling stress conditions (intervention action), and after stress removal, to improve regeneration.

Short-term Storage of Seeds and Cryopreservation of Embryonic Axes of Lepisanthes fruticosa

Aims: This work highlights short-term storage of recalcitrant Lepisanthes fruticosa seeds and long-term conservation attempts of its embryonic axes (EAs) through cryopreservation. Study design: This study adopted the Completely Randomized Design (CRD). Ten samples were used for each experiment and replicated for 3 – 5 times. Place and Duration of Study: Cryopreservation Laboratory, Agrobiodiversity and Environment Research Centre, MARDI Headquarters, Malaysia, in 2017 and 2018. Methodology: Short-term storage was carried out using fresh seeds at 54% moisture content and stored at 8±1 °C and 25±2 °C for 7 weeks. Three variations to sterilization were attempted to optimize survival while keeping contamination low. Cryopreservation using two different methods were tested, namely vitrification and the encapsulation vitrification method. Vitrification technique involved the pre-culturing of EAs overnight in different sucrose pre-culture concentrations (0, 0.2, 0.4 and 0.6 M) prior to, loading, dehydration with vitrification solution (PVS2), rapid immersion into liquid nitrogen (-196°C), rapid warming, unloading and recovery. While, encapsulation vitrification involved encapsulation of the EAs using 3% sodium alginate followed by exposure to different duration (0, 10, 20, 30, 40 and 50 minutes) of vitrification solution (PVS2) prior to cryopreservation. Results: L. fruticosa seeds can be safely stored for short-term up to 7 weeks of storage either at 8±1 °C or 25±2 °C with no loss in germination. This study also showed that EA was amenable to cryopreservation and 13.33 – 66.67% of viability was obtained when the EAs were cryopreserved using the vitrification technique. The best result was obtained with 66.67% viability, when the EAs were pre-cultured with 0.4M sucrose prior to exposure to PVS2 and liquid nitrogen. Cryopreservation of EAs using the encapsulation-vitrification method was unsuccessful. Conclusion: Seeds of L. fruticosa can be stored for short-term (up to 7 weeks) using hydrated/non-dried seeds where they can be successfully stored at 8±1 °C and 25±2 °C for up to 7 weeks. For long-term (cryopreservation), EAs can be cryopreserved upon pre-culture with 0.4M sucrose prior to exposure to PVS2 and liquid nitrogen through vitrification technique.

Short-term storage of seeds and cryopreservation of embryonic axes of Lepisanthes fruticosa

This work highlights short-term storage of recalcitrant Lepisanthes fruticosa seeds and long-term conservation attempts of its embryonic axes (EAs) through cryopreservation. Short-term storage was carried out using fresh seeds at 54 % moisture content and stored at 8 ±1 °C and 25 ±2 °C for 7 weeks. Three variations to sterilization were attempted to optimize survival while keeping contamination low for cryopreservation. Cryopreservation using two different methods were tested, namely vitrification and the encapsulation vitrification method. Vitrification technique involved the pre-culturing of EAs overnight in different sucrose pre-culture concentrations (0, 0.2, 0.4 and 0.6 M) prior to, loading, dehydration with plant vitrification solution (PVS2), rapid immersion into liquid nitrogen (-196 °C), rapid warming, unloading and recovery. While, encapsulation vitrification involved encapsulation of the EAs using 3 % sodium alginate followed by exposure to different duration (0, 10, 20, 30, 40 and 50 minutes) of PVS2 prior to cryopreservation. L. fruticosa seeds can be safely stored for short-term with no loss in germination up to 7 weeks of storage either at 8 ±1 °C or 25 ±2 °C. This study also showed that EA of L. fruticosa was amenable to cryopreservation, 13.0 – 66.67% of viability was obtained when the EAs were cryopreserved using the vitrification technique while the best result was obtained (66.67 % viability) when the EAs were pre-cultured with 0.4 M sucrose prior to exposure to PVS2 and liquid nitrogen. Cryopreservation of EAs using the encapsulation-vitrification method was unsuccessful.