Regeneration Of Somatic Embryos Research Articles

Effect of Salicylic Acid in Inhibiting Fungal Contamination in in vitro Cultures of Date Palm (Phoenix dactylifera L.) and Enhancing Embryogenesis and Plantlet Development

Abstract In this study, we evaluated the role of salicylic acid in diminishing fungal contamination in in vitro cultures of date palm and the effect of salicylic acid on the regeneration of somatic embryos from callus formed on shoot tips. The most prevalent fungi were Alternaria alternata (37%), Fusarium solani (25%), Aspergillus fumigatus (18%), and Penicillium expansum (6%). Salicylic acid limited and at higher concentrations retarded mycelial growth using potato dextrose agar. Salicylic acid at concentrations of 1.5 and 2.0 mM added to MS medium with 2iP and NAA significantly increased the embryogenesis rate of calli explants to 64.9% and 56.7%, respectively, compared with the control (12.3%). Salicylic acid also increased plantlet development from embryos by about 27% compared with the control. Salicylic acid caused better shoot and root growth and increased chlorophyll content. The results showed that the addition of salicylic acid at 1.5 mM to the MS medium resulted in a significant increase in the concentrations of IAA and ABA, as well as a decrease in the concentration of IBA in leaves.

The use of auxin to regenerate embryogenic callus of Indonesian local garlic varieties

Abstract Garlic is a national priority commodity with regards to reducing imports. One of the obstacles in its national production is the limitation of seed quality. This study aimed to investigate how auxin impacts the regeneration of embryogenic callus in three local garlic varieties. The experiment employed a two-factor Complete Randomized Design, involving varieties (Lumbu Putih, Geol, and Sangga Sembalun) and auxin types: A (IAA 1 ppm), B (IAA 3 ppm), C (IAA 5 ppm), D (IBA 1 ppm), E (IBA 3 ppm), and F (IBA 5 ppm). Each treatment was repeated three times so that the total treatment was 54 experimental units. Embryogenic calli, weighing about 0.2 g, were cultivated on the treatment medium. The observed variables were the diameter and texture of the callus, as well as the number of green spots on the callus. The results showed no significant interaction between variety and auxin treatment, but variety had a significant effect on callus diameter. The largest callus diameter was shown by the Sangga Sembalun variety under treatment C (2.75 mm) with a friable texture, yellowish color, and rooted structure, while the smallest callus diameter was produced by the Geol variety in treatment E (1.20 mm) with a non-friable texture and white color. The highest number of green spots was also produced from Sangga Sembalun in treatment D (7 green spots). It was concluded that auxin plays a role in the regeneration of somatic embryos in garlic, but its effectiveness depends on the genotype.

Effects of Plant Growth Regulators on Somatic Embryo Regeneration of Liriope spicata

Effects of Plant Growth Regulators on Somatic Embryo Regeneration of Liriope spicata

Enhancing the regeneration of TIS-derived somatic embryos of oil palm (Elaeis guineensis Jacq.) with CaCl2 and GA3

Micropropagation of oil palm through somatic embryogenesis (SE) technique provides clonal and uniform seedlings as high-quality planting materials for plantation. However, a problem associated with oil palm SE is the low regeneration rate of the somatic embryos. It was revealed that nutrient balance played a vital role in the success of SE regeneration. Therefore, a study was conducted to determine the balance between a macronutrient, calcium, and the germination-inducing hormone, Gibberellin (GA3) in enhancing the regeneration of the oil palm somatic embryos derived from the Temporary Immersion System (TIS). Treatments consist of various concentrations of CaCl2 (440, 880, or 1320 mg L-1) and enrichment of GA3 (2 or 4 mg L-1) applied into SE regeneration media, followed by the observation of regeneration rate and shoot tip necrosis after five weeks of culture. The study revealed that CaCl2 in the concentration of 880 mg L-1 was the best in stimulating oil palm TIS-derived SE regeneration. A higher concentration of GA3 (4 mg L-1) was needed in the first transition of SE from TIS into SE regeneration media in solid culture, while further SE-derived shoots development needed a lower concentration of GA3.

Browning prevention of oil palm somatic embryos in the temporary immersion system with antioxidant mixture and modification of basal media

Browning on in vitro culture is one of the problems in somatic embryo regeneration that leads to growth inhibition and death of explants. This study aimed to prevent and control browning of oil palm somatic embryos (SE) in the Temporary Immersion System (TIS). The research was conducted in two stages; the first stage was applying an antioxidant mixture at concentrations of 20, 50, and 100 mg L-1 on the browning palm oil SE in TIS. The second stage was carried out by modification of the basal media, namely DF (control), MS, SM, and SMT. The explants used in experiment 2 were browning and fresh SE. The results showed that using 50 ppm antioxidants mixture increased the formation of new SE by up to 15 embryos per flask. Applying SMT basal media on browning SE could decrease browning rate sharply after two cycle cultures by up to 60% browning rate reduction. In this media, it was also seen that the number of new SE increased by up to 250 embryos and produced 15 germinants, while in control, only 60 SE and five germinants were formed. Whereas using SMT basal medium on fresh embryos could prevent browning and increase the formation of new embryos and germinants. In conclusion, using 50 ppm antioxidants can stimulate the formation of new embryos. Using SMT basal media could prevent browning and overcome the occurrence of browning in embryos by increasing the formation of new embryos and germinants.

Proper doses of brassinolide enhance somatic embryogenesis in different competent Korean pine cell lines during embryogenic callus differentiation.

Somatic embryogenesis of Korean pine (Pinus koraiensis Sieb. Et Zucc.), an ecologically and econimically very important conifer species, was hindered by the gradually weakens and fast runaway of the embryogenicity and embryo competence of the embryogenic callus. Brassinolide (BL) has shown the enhancing capability of somatic embryo regeneration. For checking the function of BL in this issue, we applied different concentrations of BL to Korean pine callus materials exhibiting different embryogenic capacities and subsequently monitored the physiological alterations and hormone dynamics of the embryogenic callus. Our study revealed that calli with different embryogenic strengths responded differently to different concentrations of BL, but the effect after the addition of BL was very uniform. The addition of BL during the proliferation phase of embryogenic callus may help to stimulate the biological activity of callus during the proliferation process and improve the level of cell metabolism, which is accompanied by a reduction in storage substances. BL could reduce the level of endogenous auxin IAA in embryogenic callus and increase the level of abscisic acid to regulate cell division and differentiation. In addition, the MDA content in the callus was significantly decreased and the activity of antioxidant enzymes was significantly increased after the addition of BL. During the proliferation of embryogenic callus, BL was added to participate in the metabolism of phenylpropane in the cells and to increase the activity of phenylalanine ammonia-lyase and the content of lignin in the cells. We deduced that the proper doses of BL for Korean pine embryogenic callus culture were as follow: calli with low, high and decreasing embryogenicity were subcultured after the addition of 0.75 mg/L, 0.35 mg/L, 2.00 mg/L BL, respectively, during proliferation culture stage.

Suplementação do silício aumenta a regeneração in vitro de embriões somáticos de palma de óleo (Elaeis guineensis Jacq.)

ABSTRACT The use of silicates in plant tissue culture has resulted in positive effects regarding the morphological, anatomical and physiological characteristics of in vitro plants. However, biological responses to this mineral are dose and genotype dependent. The objective of the present study was to evaluate the influence of silicon supplementation on the somatic embryogenesis of oil palm (Elaeis guineensis Jacq.). The study was carried out in three stages of the cloning process, namely: Regeneration (i) and germination (ii) of somatic embryos and during ex vitro acclimatization (iii) of regenerated plantlets. The culture media were supplemented with four doses (0.0, 0.5, 1.0 and 1.5 g L-1) of calcium silicate (CaSiO3). The resulting plantlets were transplanted and acclimatized in a greenhouse. The regression analysis showed that the dose of 0.63g L-1 of CaSiO3 induced a higher rate of regeneration, which would allow a 58% increase in the number of somatic embryos formed. However, the germination of the plantlets, as well as their morphometric characters, were not affected by the different doses of CaSiO3, although the presence of this compound promoted an increase in the thickness of the epidermis and a reduction in the amount of epicuticular wax. Overall, silicon does contribute to the cloning of E. guineensis.

Study on rapid multiplication of two hybrid Arabica coffee varieties F1 Centroamericano (H1) and Mundo Maya (H16) through somatic embryogenesis and Bioreactor technology

In this paper, the research focuses on determining some components and culture conditions in order to optimise the 4 main steps of somatic embryogenesis and embryo regeneration by Bioreactor of two Arabica F1 coffee varieties H1 and H16, including: (1) formation of embryogenic callus, (2) multiplication of embryogenic cells, (3) embryonic differentiation, and (4) regeneration of somatic embryo using the temporary immersion Bioreactor RITA 1L. The results showed that on the medium supplemented with Kinetin 2 mg/ll and Phytagel 4 g/l, the callus formation rate reached 94.2 and 92.1% for 2 varieties H1 and H16, respectively. Besides, the addition of Glycine 20 mg/l to the culture medium increased the embryogenic callus rate by 58.1% in both varieties. Adding Trichostatin A 0.03 mg/l in the embryo differentiation medium in the first 7 days of culture showed that the number of torpedo embryos was scored from 1g of initial callus up to 1287 in H1 and 1635 in H16. Finally, using Bioreactor 1L-RITA, soaking for 1 min every 6 hours, the regeneration efficiency reached 75.02% in H1 and 82.03% in H16.

Somatic Embryogenesis of Myrciaria dubia (Kunth.) McVaugh

Myrciaria dubia (caçari or camu-camu) is a species with great relevance because of its high levels of bioactive compounds and antioxidant activity. The species is propagated mainly by seed, which leads to high genetic diversity. Producing plants that maintain their characteristics on a large scale at a low cost is a challenge for fruit species, especially in the Myrtaceae family. Therefore, this study aimed at assessing the effects of different plant growth regulators at various concentrations for the induction of somatic embryogenesis from caçari nodal segments and leaf disk explants. Two independent experiments were performed using nodal segments and leaf disks from plants grown in the greenhouse. In the first experiment, the combined effect of auxin and cytokinin at different concentrations was evaluated: 2,4-dichlorophenoxyacetic acid at 0, 1, 2, and 4 mg⋅L–1; and benzylaminopurine at 0, 0.25, 0.5, and 1 mg⋅L–1). In the second experiment, the application of different plant growth regulators (benzylaminopurine, kinetin, thidiazuron, and isopentenyl adenine) and their concentrations (0, 2, 4, and 6 mg⋅L–1) were evaluated. In both experiments, the basic culture medium was woody plant medium. Callus formation via nodal segments and leaf disks occurred in the first 30 d from cultivation and proved to be responsive to induction by 2,4-dichlorophenoxyacetic acid and benzylaminopurine. Auxin proved to be essential for somatic embryogenesis induction in nodal segments using 1 and 4 mg⋅L–1 of 2,4-dichlorophenoxyacetic acid alone. The results of this experiment will help advancing protocols for regeneration of somatic embryos and elucidating the physiological, molecular, and genetic mechanisms involved in the process of somatic embryogenesis for M. dubia. The development of an efficient protocol for in vitro clonal propagation of this species also lays the groundwork for further optimization of the system for genetic transformation.

Functional Analysis of Glucose-6-Phosphate Translocator PoGPT1 in Embryogenic Callus Formation of Tree Peony

Tree peony (Paeonia ostii) is an ornamental flowering plant that is generally recalcitrant to establishment of a mature somatic embryo regeneration system in vitro. Glucose-6-phosphate translocator (GPT) plays an important regulatory role in embryogenesis of plants. In this study, PoGPT1 was cloned, and a bioinformatic analysis and functional verification of the gene were performed. The results showed that PoGPT1 encoded a polypeptide of 392 amino acids, which was a basic non-secreted hydrophobic transmembrane protein, and was mainly localized in the plastids. PoGPT1 was highly expressed in tree peony leaves, and its transcript abundance increased with the progression of zygotic embryo development. Overexpression of PoGPT1 caused up-regulation of leafy cotyledon 1 (PoLEC1), somatic embryogenesis receptor-like kinase (PoSERK), and agamous-like15 (PoAGL15) in tree peony callus. In addition, PoGPT1 overexpression promoted the increase in indole-3-acetic acid (IAA), 5-deoxystrigol (5DS), and brassinolide (BL) contents, especially of IAA, but reduced the contents of abscisic acid (ABA), 6-benzyladenosine (BARP), and 1-aminocyclopropanecarboxylic acid (ACC). The present research showed that PoGPT1 synergistically regulated the contents of endogenous hormones and expression levels of embryogenesis-related genes to promote the embryonic development of tree peony. The results provide theoretical and technical support for the establishment of a tree peony embryogenic callus formation and subsequent research on somatic embryogenesis.

Different Cell Types Affect the Transition from Juvenile to Mature Phase in Citrus Plants Regenerated through Somatic Embryogenesis.

Robust protocols for the regeneration of somatic embryos in vitro are essential for the efficient use of the most modern biotechnologies. Unfortunately, in perennial trees such as Citrus, plants regenerated from juvenile tissues usually exhibit strong, undesirable juvenile characters such as thorny habit and delayed flowering and fruit production. In this work, we tested whether the cell types (nucellar and stigma/style) used to regenerate Citrus plants through somatic embryogenesis affected the transition from the juvenile to mature phase. The results show that regenerants from nucellar cells presented persistent juvenile characters, whereas plants originating from stigma/style explants transited to the mature phase more rapidly. Our observations support the hypothesis that the totipotent cells originated from different cell types are not equivalent, possibly by maintaining memory of their previously differentiated state.

Optimization of Somatic Embryo Regeneration of <i>Larix olgensis</i> Through Multiple Media

To establish a stable and efficient  Larix olgensis  somatic embryo regeneration system. In this study, immature zygotic embryos of  Larix olgensis  were used as explant materials for embryogenic callus induction, and embryogenic callus with good growth were selected to induce somatic embryo formation by liquid medium A, semi-solid medium B, and solid medium C. The callus induction medium is S medium+2,4-D 1.0 mg/L + 6-BA 0.5 mg/L + KT 0.3 mg/L, sucrose 20 g/L, agar 3 g/L; the subculture medium is S medium+2, 4-D 0.15 mg/L + 6-BA 0.05 mg/L + KT 0.05 mg/L, sucrose 30 g/L, agar 6 g/L. Mature medium A is S medium + PEG4000 100 g/L + ABA 15 mg/L + AgNO 3  10 mg/L, sucrose 45 g/L liquid medium. Mature medium B and C are mature medium A supplemented with 2 g/L and 10 g/L agar, respectively. The maturation time of this method is about 32 days, the synchronization rate is 78.0%, and the proportion of somatic embryos in normal morphology is 83.0%. Somatic embryo formation efficiency in normal morphology can reach 223.0 embryos/g embryogenic callus, somatic embryo germination rate can reach 47.2%. Compared with a single maturation medium, the maturation time is shortened, somatic embryo generation is more synchronized, and high somatic embryo yield and quality are improved. It provides a way for the commercialization of somatic embryo regeneration of  Larix olgensis , brings great convenience to large-scale breeding and reproduction, physiological and biochemical research, and genetic modification, and has great practical application value.

Callogenesis and Embryogenic Potential of New Superior Cocoa (Theobroma cacao L.) Genotypes Treated with Ascorbic Acid

Clonal propagation is an alternative method of maintaining the genetic purity of superior cocoa plants (Theobroma cacao L.). The somatic embryogenesis technique is likely the most effective and efficient method for plant propagation. This study aimed at investigating the callogenesis and embryogenic potential of new superior cocoa clones on culture media added with various concentrations of antioxidants and variation in the concentration of auxin hormone combined with ascorbic acid. The superior clones used in this study were MCC 01, MCC 02, Sulawesi 3, ICCRI 07, and ICCRI 09. The parameters observed in this study were percentage of embryogenic callus formation, number of secondary somatic embryos, and percentage of embryo somatic cells that develop into planlets. The addition of 2,4,5-T combined with ascorbic acid affected the initiation of cocoa secondary somatic embryogenesis. Treatment combination of ascorbic acid 100 mg.L-1 and 2,4,5-T 1 mg.L-1 had a significant effect on the initiation of secondary somatic embryogenesis of cocoa in the embryogenic callus phase (4.73%), globular embryos (2.53%), torpedo embryos (4.67%) and sprouts (0.47%). Three clones i.e ICCRI 07, Sulawesi 3 and ICCRI 09 clones showed a higher percentage (3.0%, 2.10%, and 1.80%, respectively) of embryogenic callus growth than the other clones. Meanwhile, on MCC 01 clone, all treatments did not affect the regeneration of embryogenic callus. The combination treatment of organic acid and adenine showed a low embryogenic callus response in MCC 01 and MCC 02 clones. However, MCC 02 clone also did not show a response in form of globular, torpedo, and germination phase somatic embryo regenerations. This indicates that different plant cultivars show different responses to the addition of organic acids. Treatment combinations of adenine 0.0125 mg.L-1 + ascorbic acid 100 mg.L-1 gave the best response to the regeneration of somatic embryos for the globular, torpedo, and g

Genomic Methylated Cytosine Level during the Dedifferentiation and Cellular Competence in Coffea arabica Lines: Insights about the Different In Vitro Responses

Coffea arabica genotypes present distinct responses in vitro, and somaclonal variation occurrence has been reported. Global cytosine methylation is one of the epigenetic mechanisms that influences the Coffea in vitro responses. We aimed to establish the indirect somatic embryogenesis in C. arabica ‘Catuaí Vermelho’, ‘Caturra’ and ‘Oeiras’, associate the distinct responses to the methylated cytosine genomic level, and check the ploidy stability. Leaf explants were cultured in callus induction and proliferation medium. The resulted calli were transferred to the regeneration medium, and the mature cotyledonary somatic embryos were transferred to the seedling medium. ‘Oeiras’ exhibited the highest number of responsive leaf explants, followed by ‘Caturra’ and ‘Catuaí Vermelho’. Global methylated cytosine level increased over time in the ‘Catuaí Vermelho’ and ‘Caturra’ friable calli, remaining constant in ‘Oeiras’. ‘Oeiras’ did not regenerate somatic embryos, while ‘Catuaí Vermelho’ exhibited the highest number. Somatic embryo regeneration was associated with the increase of the methylated cytosine level. However, the ‘Catuaí Vermelho’ embryogenic calli showed a lower methylated cytosine level than ‘Caturra’. Recovered plantlets exhibited the same 2C value and chromosome number to the explant donors. Therefore, cytosine hypermethylation occurred during C. arabica indirect somatic embryogenesis, influencing cell competence and somatic embryos regeneration.

Shallot haploid breeding for sustainable production-callus induction from shallot anther tissues

Shallot is an essential vegetable crop in Indonesia, and its cultivation requires labor and capital intensive. Availability of high yielding and disease resistant shallot varieties will ensure its sustainable production. Haploid breeding should be beneficial for supporting the shallot breeding program. This study aims to identify suitable media for inducing callus growth and subsequent shoots or somatic embryo (SE) regeneration from anther tissues. In this study, successful callus induction was obtained from shallot anther but not for shoots or SE regeneration. The three different flower-sized responses were also investigated, and large flowers (5mm x 3mm) with an average anther length of 1.44 ± 0.04 mm were the best for callus induction. The microscopic observation indicated that large and medium flowers contain most bicellular pollen developmental stages, while small flowers are mostly tetrad stage. It also showed that the bicellular stage was more responsive to callus induction than the tetrad one. Moreover, the C1 medium consisted of MS basal medium supplemented with 3 mg L−1 BAP, 3 mg L−1 NAA, and 30 g/L sucrose was the best medium for inducing callus from anther explant.

Development and regeneration of somatic embryos from leaves-derived calli of Coffea liberica

Abstract. Ardiyani F, Utami ESW, Purnobasuki H, Paramita SA. 2020. Development and regeneration of somatic embryos from leaves-derived calli of Coffea liberica. Biodiversitas 21: 5829-5834. Coffea liberica is an important and potentially commercial plant with a high economic value from the Coffea genus. Therefore, the availability of planting material is needed to increase productivity and ensure the sustainability of its farming. Somatic embryogenesis is a powerful propagation method used to produce clonal plants from limited genetic material. In the present research, we have shown that C. liberica could be successfully regenerated in vitro via somatic embryogenesis from leaves derived embryogenic callus. These calli were cultured on Murashige Skoog (MS) medium added with 1 mgL-1 BAP or in combination with 2.4 D (0.5, 1.0, 1.5 and 2 mgL-1) for embryo development induction. Furthermore, the medium containing only BAP was best for embryo development induction after culturing for 12 weeks, with the highest number of cotyledonary stage embryos (17.8%) and producing a total of embryo (20.2). Following cotyledonary stage embryo were cultured on new MS medium containing 0.5 mgL-1 BAP, 0.5 mgL-1 IAA, 0.5 mgL-1 NAA only, and 0.5 mgL-1 BAP in combination with 0.5 mgL-1 IAA or 0.5 mgL-1 NAA. Interestingly, the results showed that cotyledonary stage embryos were converted into complete plants at all treatment, but the MS medium containing 0.5 mgL-1 BAP was found to be the most effective in promoting regeneration with 2.6 leaves per-plantlet and height of 5.2 mm. Based morphological analysis confirm that the development of somatic embryo from leaves-derived calli of Coffea liberica started with the formation of embryo globular, heart, torpedo, cotyledonary stages, and finally conversion of cotyledonary embryo into complete plant.

Global 5-methylcytosine and physiological changes are triggers of indirect somatic embryogenesis in Coffea canephora.

Indirect somatic embryogenesis (ISE) establishment for Coffea species started in the 1970s. Since then, intraspecific variations in the morphogenic pathway have been reported, even in the common environmental condition in vitro. Several authors have suggested that these variations are the result of genetic, epigenetic, and/or physiological events, highlighting the need for investigations to know the causes. Along these lines, this study aimed to investigate and describe, for the first time, the global 5-methylcytosine and physiological changes that occur in the cells of the aggregate suspensions of Coffea canephora during proliferation and somatic embryo regeneration steps. The cell proliferation step was characterized by increase in cell mass in all subcultures; relatively low mean values of global 5-methylcytosine (5-mC%), abscisic acid (ABA), and indole-3-acetic acid (IAA); high mean value of 1-aminocyclopropane-1-carboxylic acid (ACC, an ethylene precursor); and increase followed by decrease in spermidine (Spd, a polyamine) level. Therefore, these epigenetic and physiologic aspects promoted the cell proliferation, which is fundamental for ISE. In turn, the somatic embryo regeneration was correlated with global 5-mC% and physiological changes. The competence acquisition, determination, and cell differentiation steps were marked by increases in mean values of 5-mC%, IAA and ABA, and decreases in ACC and Spd, evincing that these changes are the triggers for regeneration and maturation of somatic embryos. Therefore, dynamic and coordinated epigenetic and physiologic changes occur in the cells of the aggregate suspensions during the C. canephora ISE in liquid system.

In vitro somatic embryogenesis of superior clones of robusta coffee from Lampung, Indonesia: Effect of genotypes and callus induction media

Abstract. Hapsoro D, Hamiranti R, Yusnita Y. 2020. In vitro somatic embryogenesis of superior clones of robusta coffee from Lampung, Indonesia: Effect of genotypes and callus induction media. Biodiversitas 21: 3811-3817. This study aimed to investigate the effects of genotypes and primary callus induction media on somatic embryogenesis of superior robusta coffee clones of Lampung. Leaf explants of clones Tugusari, Komari, Tugino, and Wanto were cultured on two types of primary callus induction media (PCIM). PCIM1 consisted of half-strength MS salts, 30 gL-1 sucrose, added with (mgL-1) 0.1 thiamine-HCl, 0.5 nicotinic acids, 0.5 pyridoxine-HCl, 100 Myo-inositol, 200 ascorbic acids, 150 citric acids, and 1 benzyl adenine. PCIM2 consisted of NPCM salts, 30 gL-1 sucrose, added with (mgL-1) 15 thiamine-HCl, 1 nicotinic acid, 1 pyridoxine-HCl, 2 glycines, 130 Myo-inositol, 200 ascorbic acids, 150 citric acids, 1 2,4-dichlorophenoxyacetic acid, and 2 thidiazuron. The highest percentage (100%) of primary callus formation was found in Komari and Wanto clones. PCIM2 resulted in more primary calli than PCIM1. When subcultured to embryogenic callus induction medium, primary calli of clone Komari and Wanto developed into a high percentage of embryogenic calli, while those of the other two turned brown and died. PCIM2-derived primary calli developed into more embryogenic calli. When subcultured on somatic embryo (SE) regeneration medium, these calli underwent the formation of SE of various stages. When subcultured to plant regeneration medium, these SEs developed into plantlets.

Gibberellins and light synergistically promote somatic embryogenesis from the in vitro apical root sections of spinach

Gibberellins (GAs) play a pivotal role in the induction of somatic embryogenesis from in vitro root apices of spinach plants. With the aim to understand the role of GAs in this process and to improve somatic embryo (SE) regeneration efficiency, the impact of light and GAs on SE initiation from the in vitro root apices was studied. The root sections were isolated from in vitro-grown SE-derived plants and placed on medium containing 20 µM α-naphthaleneacetic acid (NAA) and 0–10 µM GA3 or GA1, and cultivated under light conditions or in darkness. The most efficient SE regeneration response (100% regenerating SEs and 40.73 SEs per root apices) was achieved only in the presence of both light and GAs, with GA3 always exhibiting much stronger effect than GA1. Considering that light enhances GAs biosynthesis and the necessity of GAs for SE initiation, the expression levels of genes encoding the key enzymes involved in the final steps of GAs synthesis (SoGA20-ox1 and SoGA3-ox1) and deactivation (SoGA2-ox1, SoGA2-ox2 and SoGA2-ox3) were analyzed. Light enhanced the expression of all five GA-ox genes, while exogenously supplied NAA + GA3 provoked downregulation of SoGA20-ox1 and SoGA3-ox1 and upregulation of SoGA2ox-2 and SoGA2ox-3 expression. The expression of SoGA2ox-1 only slightly decreased. The results indicated the capability of isolated spinach roots to perceive the light and autonomously produce GAs. The expression levels of genes encoding key enzymes involved in GA biosynthesis suggest that lower levels of GAs favor SE initiation. Light and gibberellins (GA) synergistically promote somatic embryogenesis in spinach. Expression levels of genes encoding key enzymes for GA metabolism suggest that lower levels of GAs may favor somatic embryogenesis.

Effect of desiccation on somatic embryo regeneration in date palm (Phoenix dactyliferaL.) cultured in vitro

ISHS XXX International Horticultural Congress IHC2018: II International Symposium on Micropropagation and In Vitro Techniques Effect of desiccation on somatic embryo regeneration in date palm (Phoenix dactylifera L.) cultured in vitro