scholarly journals Long-Term Maintainable Somatic Embryogenesis System in Alfalfa (Medicago sativa) Using Leaf Explants: Embryogenic Sustainability Approach

Plants ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 278 ◽  
Author(s):  
Ankush Sangra ◽  
Lubana Shahin ◽  
Sarwan K. Dhir

Alfalfa (Medicago sativa) is one of the most important forage legume crops because of its mass production and high feeding value. It originated in Asia and is one of the most ancient plants cultivated throughout the world as a fodder. Despite the well-studied somatic embryogenesis of alfalfa, there is a lack of a long-term maintainable somatic embryogenic system. Every time an embryogenic callus culture must be started from new explants, which is laborious, costly and time consuming. In addition to this, endogenous microorganisms present in ex vitro explants of alfalfa can often cause contamination, reducing the efficiency of callus culture. An attempt was made to establish long-term continuous somatic embryogenesis system in alfalfa using cultivar Regen-SY. Nine somatic embryogenesis pathways were studied and evaluated for embryo yield, plant conversion rate and embryogenic sustainability. Somatic embryos passed through the same stages (globular, heart-shaped, torpedo and cotyledonary) as characteristic of the zygotic embryo and secondary somatic embryogenesis was also observed. B5H-B5 system showed the highest embryo yield and plant conversion rate whereas SH4K-BOi2Y system demonstrated the highest embryogenic sustainability and maintained the embryogenic potential even after six subculture cycles. Scanning electron microscopy was applied to study the morphology of the somatic embryos and secondary somatic embryogenesis. Therefore, long-term maintainable somatic embryogenesis system protocol was developed through this study, which will help to enhance and accelerate the alfalfa biotechnology research.

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jingli Yang ◽  
Songquan Wu ◽  
Chenghao Li

Embryogenic callus was obtained from mature seed explants on medium supplemented with 2,4-dichlorophenoxyacetic acid. Primary somatic embryos (SEs) can only develop into abnormal plants. Well-developed SEs could be obtained through secondary somatic embryogenesis both in solid and liquid cultures. Temperature strongly affected induction frequency of secondary embryogenesis. Relatively high temperature (30∘C) and germinated SEs explants were effective for induction of secondary somatic embryos, and low temperature (20∘C) was more suitable for further embryo development, plantlet conversion, and transplant survival. Somatic embryos formed on agar medium had larger cotyledons than those of embryos formed in liquid medium. Supplementing 0.1 mg L−16-benzyladenine (BA) was effective for plant conversion; the rate of plant conversion was 43.3% in somatic embryos from solid culture and 36.5% in embryos from liquid culture.In vitroplants were successfully acclimatized in the greenhouse. The protocol established in this study will be helpful for large-scale vegetative propagation of this medicinal tree.


HortScience ◽  
2004 ◽  
Vol 39 (6) ◽  
pp. 1378-1380 ◽  
Author(s):  
C.K. Kim ◽  
J.Y. Oh ◽  
J.D. Chung ◽  
A.M. Burrell ◽  
D.H. Byrne

Somatic embryogenesis was initiated from in vitro-grown leaf explants of rose using an induction period of 4 weeks on MS basal medium supplemented with auxin followed by several subcultures on MS basal medium with cytokinin. `4th of July' showed the highest regeneration frequency (24.4%) on 5.3 μm NAA followed by culture on medium containing 18.2 μm zeatin. `Tournament of Roses' produced somatic embryos when cultured for 4 weeks on medium containing dicamba, 2.3 μm followed by three subcultures on medium containing 18.2 μm zeatin. Embryogenic callus matured on MS media containing 0.5 μm NAA, 6.8 μm zeatin, and 2.9 μm GA3. Long-term cultures were established for both cultivars. Somatic embryos germinated on MS medium containing IBA and BA. Silver nitrate (58.8 μm) enhanced shoot formation and germination of somatic embryos. Plants derived from somatic embryos were acclimatized and successfully established in the greenhouse.


1970 ◽  
Vol 19 (1) ◽  
pp. 89-99
Author(s):  
K. Choudhary ◽  
M. Singh ◽  
M. S. Rathore ◽  
N. S. Shekhawat

This long term study demonstrates for the first time that it is possible to propagate embryogenic Vigna trilobata and to subsequently initiate the differentiation of embryos into complete plantlets. Initiation of callus was possible on 2,4-D. Somatic embryos differentiated on modified MS basal nutrient medium with 1.0 mg/l  of 2,4-D and 0.5 mg/l  of Kn. Sustained cell division resulted in globular and heart shape stages of somatic embryos. Transfer of embryos on to a fresh modified MS basal medium with 0.5 mg/l of Kn and 0.5 mg/l of GA3 helped them to attain maturation and germination. However, the propagation of cells, as well as the differentiation of embryos, were inhibited by a continuous application of these growth regulators. For this reason, a long period on medium lacking these growth regulators was necessary before the differentiation of embryos occurred again. The consequences for improving the propagation of embryogenic cultures in Vigna species are discussed. Key words: Pasture  legume, Vigna trilobata, Globular, Heart shape, somatic embryogenesis D.O.I. 10.3329/ptcb.v19i1.4990 Plant Tissue Cult. & Biotech. 19(1): 89-99, 2009 (June)


Plants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 70
Author(s):  
Ana D. Simonović ◽  
Milana M. Trifunović-Momčilov ◽  
Biljana K. Filipović ◽  
Marija P. Marković ◽  
Milica D. Bogdanović ◽  
...  

Centaurium erythraea (centaury) is a traditionally used medicinal plant, with a spectrum of secondary metabolites with confirmed healing properties. Centaury is an emerging model in plant developmental biology due to its vigorous regenerative potential and great developmental plasticity when cultured in vitro. Hereby, we review nearly two decades of research on somatic embryogenesis (SE) in centaury. During SE, somatic cells are induced by suitable culture conditions to express their totipotency, acquire embryogenic characteristics, and eventually give rise to somatic embryos. When SE is initiated from centaury root explants, the process occurs spontaneously (on hormone-free medium), directly (without the callusing phase), and the somatic embryos are of unicellular origin. SE from leaf explants has to be induced by plant growth regulators and is indirect (preceded by callusing). Histological observations and culture conditions are compared in these two systems. The changes in antioxidative enzymes were followed during SE from the leaf explants. Special focus is given to the role of arabinogalactan proteins during SE, which were analyzed using a variety of approaches. The newest and preliminary results, including centaury transcriptome, novel potential SE markers, and novel types of arabinogalactan proteins, are discussed as perspectives of centaury research.


1995 ◽  
Vol 43 (4) ◽  
pp. 385-390 ◽  
Author(s):  
S. Kulothungan ◽  
A. Ganapathi ◽  
A. Shajahan ◽  
K. Kathiravan

Embryogenic callus was induced from seedling leaf explants of cowpea (Vigna unguiculata (L.) Walp. cv. C152 on Murashige and Skoog (MS) medium containing 2.0 mg 1−1 2,4-dichlorophenoxyacetic acid (2,4-D). The maximum frequency of somatic embryogenesis was noticed when this callus was transferred to MS liquid medium supplemented with 2 mg 1−1 2,4-D. Further studies on ontogeny of somatic embryos showed that the cells destined to become somatic embryos divided into spherical or filamentous proembryos. Subsequent divisions in the proembryo led to globular, heart, torpedo-shaped, and cotyledonary-stage somatic embryos. Tiny plantlets were obtained by transferring the cotyledonary-stage somatic embryos to MS liquid medium containing 0.5 mg 1−1 2,4-D.


2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Dipasree Roychowdhury ◽  
Binay Chaubey ◽  
Sumita Jha

The fate of integrated Ri T-DNA rol genes during regeneration via indirect somatic embryogenesis and stability of its effect on morphology and tylophorine content of Ri-transformed plants have been studied in Tylophora indica. Integration and expression of Ri T-DNA genes in transformed embryogenic callus lines derived from transformed root lines, 300 Ri-transformed somatic embryos, and 23 Ri-transformed plant lines were analysed. Fifty root lines studied showed integration and expression of four rol genes of TL-DNA. Spontaneous regeneration via indirect somatic embryogenesis was obtained from root lines that were TL+/TR−. Stable integration and expression of rol genes were observed in root lines, embryogenic callus lines, and the spontaneously induced somatic embryos. Nineteen out of the 23 Ri-transformed plant lines and their clones showed phenotypic and genetic stability over the period of 3 years. Four Ri-transformed plants were morphologically similar to nontransformed plants but showed variation with the integration and expression of the rolA gene and absence of other rol genes. Variant Ri-transformed plant line A428#1-V showed highest tylophorine content (2.93±0.03 mg gDW−1) among plant lines studied. The effects of T-DNA genes on growth, morphology, and tylophorine content of the Ri-transformed plants were stable in the long term culture.


2018 ◽  
Vol 14 (4) ◽  
pp. 661-671
Author(s):  
Nguyen Thi Kim Loan ◽  
Do Dang Giap ◽  
Tran Trong Tuan ◽  
Nguyen Thi Thanh Hien ◽  
Nguyen Phuc Huy ◽  
...  

An efficient method for plant regeneration in Jatropha curcas L. via primary and secondary somatic embryogenesis culture from ex vitro leaves of 6-month-old plants was presented in this study. Leaves were cut into transverse thin cell layers (tTCLs) and cultured on MS medium supplemented with kinetin (KIN) at 0.5, 1.0, 1.5, and 2.0 mg/l in combination with indole-3-butyric acid (IBA) at 0.1, 0.5, and 1.0 mg/l or 2,4-dichlorophenoxyacetic acid (2,4-D) at 1.0, 1.5 and 2.0 mg/l . The highest embryogenic callus formation rate (89.3%) was obtained on medium supplemented with 1.0 mg/l KIN and 1.5 mg/l 2,4-D. The calli were selected for the study of primary somatic embryogenesis on MS medium containing 2,4-D (0.01, 0.03, 0.05, and 0.07 mg/l) or KIN (0.5, 1.0, 1.5, and 2.0 mg/l). The highest primary somatic embryos formation rate (76.67%) was achieved on MS medium supplemented with 1.0 mg/l KIN. The primary embryos were cultured on medium supplemented with KIN (0.1, 0.5, 1.0, 1.5, and 2.0 mg/l) combined with 0.2 mg/l indole-3-butyric acid (IBA) or 0.05 mg/l 2,4-D. The combination of 1.5 mg/l KIN and 0.05 mg/l 2,4-D was suitable for secondary embryos formation. Embryos proliferated rapidly, and the highest number of secondary embryos (77.5 embryos) wasobtained from a single primary embryos inoculated. Results also showed that the addition of proline (0.75 g/l) or spermidine (0.15 mM) to the culture medium increased the number of secondary embryos considerably. The fully developed plantlets exhibiting healthy roots and shoots were obtained when somatic embryos were sub-cultured onto B5 medium containing 1.5 mg/l IBA.


2018 ◽  
pp. 7-20
Author(s):  
Maria Daniela Artigas Ramirez ◽  
Rafael Fernandez Da Silva

Background and Aims: Meliaceae species are extremely recalcitrant during germination and in vitro processes. Therefore, this research focuses on characterization and optimization of a highly efficient system by secondary somatic embryogenesis in Azadirachta indica, which is an important step for enhancing secondary metabolite production and regeneration in recalcitrant species.Material and Methods: Leaf and cotyledon sections were induced in MS medium supplemented with benzylaminopurine (BAP) alone, or combined with 1-naphthaleneacetic acid (NAA) and, abscisic acid (BA) with thidiazuron (TDZ).Key results: Azadirachta indica developed primary somatic embryos with BAP. Shoot and root formation occurred at low concentrations of BAP, while somatic embryogenesis was favored under high levels of BAP or TDZ. Primary and secondary somatic embryos were evidenced continuously and asynchronously. The highest amount of somatic embryos was obtained with cytokinins. However, the concentration might be significant to differentiate between primary and secondary embryos. Moreover, the auxins are key for inducing histodifferentiation in embryos. Shoot induction occurred after transfer of the embryos to hormone-free MS medium. The shoots were rooted in MS1/2.Conclusions: The secondary somatic embryos were distinguished and characterized during the whole process and the efficient system was established with cotyledon sections at short term, which offers several advantages such as the production of metabolites.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1068b-1068
Author(s):  
R. A. Hoyos ◽  
G. L. Hosfield

Opaque globules formed on bean callus induced on primary leaf explants cultured on induction media (IM) containing 10 to 30 mg/l 2,4-D. Calli with globules produce structures reminiscent of somatic embryos (embryoids) after subculture in a liquid challenge medium (LCM). Calli maintained on IM for 2, 3, 4, and 5 weeks produced significantly more (26 to 34/callus) embryoids in LCM than calli maintained on IM for one week (12/callus). Well developed embryoids only occurred after calli were subculture in liquid B5 with 0.1 to 1.0 mg/l IBA. Calli subculture in LCM with > 10 mg/l IBA turned necrotic and died. Embryoids produced in B5 with 2,4-D and NAA (0.1 to 1.0 mg/l) proliferated roots and formed “frosty” appearing structures, respectively. No differences were detected in number or quality of embryoids produced in LCM from callus maintained on IM in continuous light or darkness regardless of the induction time. Ethylene accumulation in IM cultures inhibited globule formation.


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