Evaluation of drought resistance-related traits in durum wheat somaclonal lines selected in vitro

2004 ◽  
Vol 44 (1) ◽  
pp. 27 ◽  
Author(s):  
M. Bajji ◽  
P. Bertin ◽  
S. Lutts ◽  
J-M. Kinet

Somaclonal variation associated with in vitro selection has been used as a source of variability to improve drought resistance of 3 durum wheat (Triticum durum Desf.) cultivars (Selbera, Sebou, and Kyperounda). In a previous study, R0 plants with improved drought resistance-related characters were regenerated after selection on culture media containing polyethylene glycol (PEG). This improvement was transmitted to the R1 progeny. The present study analysed the behaviour of the selected tissue culture-derived lines in subsequent R2, R3 and R4�generations. Differences in electrolyte leakage, chlorophyll fluorescence (Fv/Fm), stomatal conductance and days to heading were found between the parental cultivars and most of their in vitro-derived lines. The changes may differ from one cultivar to another. Many promising somaclonal lines still presented improvement for at least 3 of the 4�parameters measured comparatively to initial cultivars. Somaclonal variation thus appears to induce a wide range of modifications among individual components of drought-resistance mechanisms. These improved traits could be valuable if shown to be inherited and to give enhanced agronomic performances in future field studies.

2004 ◽  
Vol 22 (2) ◽  
pp. 300-304 ◽  
Author(s):  
Patricia N. Bordallo ◽  
Derly H. Silva ◽  
José Maria ◽  
Cosme D. Cruz ◽  
Elizabeth P. Fontes

Synthetic seeds can be an alternative for those species in which botanical seeds are not viable. One of the major problems of in vitro plant cultivation is the high level of somaclonal variation. The most common factors affecting somaclonal variation are genotype, explant source, in vitro period and cultivation conditions in which the culture is established. In this work, calli were induced using leaf and stem explants of the commercial potato cultivars Achat, Baraka, Baronesa, Bintje, and Contenda in MS culture media supplemented with 1.65 mM of picloram and 11.5 mM of 2,4-D. Seventy and 90 days after induction, DNA samples of 40 calli were compared concerning the effects of the two explant (leaf and stem) and two growth regulator sources on five potatoes cultivars. A total of 20 arbitrary sequence primers were evaluated. The RAPD pattern generated by these primers suggested a high percentage of polymorphic fragments among the five genotypes, indicating a high level of genetic variation among cultivars. Cultivar Baronesa showed the highest number of polymorphic fragments for all treatments. The cultivar Contenda showed the smallest somaclonal variation, for most of the treatments, except for the treatment which consisted of stem explants, picloram (1.65 mM) application, and a 70-day period of callus formation. 'Contenda' is, therefore, the most suitable cultivar for synthetic seed production.


Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1671
Author(s):  
Ráchel Sgallová ◽  
Edward A. Curtis

Methods of artificial evolution such as SELEX and in vitro selection have made it possible to isolate RNA and DNA motifs with a wide range of functions from large random sequence libraries. Once the primary sequence of a functional motif is known, the sequence space around it can be comprehensively explored using a combination of random mutagenesis and selection. However, methods to explore the sequence space of a secondary structure are not as well characterized. Here we address this question by describing a method to construct libraries in a single synthesis which are enriched for sequences with the potential to form a specific secondary structure, such as that of an aptamer, ribozyme, or deoxyribozyme. Although interactions such as base pairs cannot be encoded in a library using conventional DNA synthesizers, it is possible to modulate the probability that two positions will have the potential to pair by biasing the nucleotide composition at these positions. Here we show how to maximize this probability for each of the possible ways to encode a pair (in this study defined as A-U or U-A or C-G or G-C or G.U or U.G). We then use these optimized coding schemes to calculate the number of different variants of model stems and secondary structures expected to occur in a library for a series of structures in which the number of pairs and the extent of conservation of unpaired positions is systematically varied. Our calculations reveal a tradeoff between maximizing the probability of forming a pair and maximizing the number of possible variants of a desired secondary structure that can occur in the library. They also indicate that the optimal coding strategy for a library depends on the complexity of the motif being characterized. Because this approach provides a simple way to generate libraries enriched for sequences with the potential to form a specific secondary structure, we anticipate that it should be useful for the optimization and structural characterization of functional nucleic acid motifs.


Author(s):  
Deep Chhavi Anand ◽  
Rishikesh Meena ◽  
Vidya Patni

Objective: The aim of the present study was to develop a callus induction protocol and comparative study of therapeutic phytochemicals present in in vivo leaf and in vitro callus extracts through Gas Chromatography-Mass Spectrometry analysis.Methods: Murashige and Skoog media was used as culture media for callus induction. In vitro callus induction protocol was developed by studying the effects of various plant growth regulators like auxin, 2, 4-D (2,4-dichlorophenoxyacetic acid), NAA (naphthalic acetic acid), alone and in combination with cytokinin BAP (benzyl aminopurine), on leaf and stem explants. The GC-MS analysis of Ampelocissus latifolia was carried out on Shimadzu QP-2010 plus with thermal desorption system TD 20 to study the phytochemical profile.Results: In vitro callus induction protocol was developed for the plant and callusing was done from leaf and stem explants of Ampelocissus latifolia. The best result for callus induction was obtained using leaf explant, and callus production were maximum in Murashige and Skoog medium fortified with BAP (0.5 mg/l) and NAA (1.0 mg/l). Major compounds identified in the GC-MS analysis were Campesterol, Stigmasterol, Beta-Sitosterol, Docosanol, Dodecanoic acid, etc., in in vitro extract and Beta Sitosterol, Tocopherol, Squalene, Bergamot oil, Margarinic acid, Hexadecanoic acid, etc., in in vivo extract. The different active phytochemicals identified have been found to possess a wide range of biological activities, thus this analysis forms a basis for the biological characterization and importance of the compounds identified for human benefits.Conclusion: This is the first report on callus induction in Ampelocissus latifolia. From the results obtained through the in vitro callus induction and its comparative GCMS analysis with in vivo extract, it is revealed that Ampelocissus latifolia contains various bioactive compounds that are of importance for phytopharmaceutical uses. The GCMS analysis revealed that the amount of Beta-sitosterol and 5-Hydroxymethylfurfural (HMF) was very high in in vitro extract as compared to in vivo extract.


HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 458E-458
Author(s):  
Carol D. Robacker ◽  
Betty Robicheaux

Micropropagation is a useful technique to propagate species such as deciduous azaleas, which are difficult to root from cuttings. To develop a micropropagation protocol that would be effective with a wide range of species and cultivars of native azalea, two culture media, Woody Plant Medium (WPM) (Lloyd and McCown, 1980) and ER medium (Economou and Read, 1994) were evaluated for ability to support growth of 11 species and four cultivars of deciduous azalea. Shoot tips were obtained from the first flush of growth in the spring on plants growing in the greenhouse or field. Following disinfection, the terminal and basal ends were removed from each explant. The explants were placed in culture tubes containing either WPM or ER medium with 12 mg/L 2iP and solidified with agar. Cultures were transferred to fresh medium every 4 to 6 weeks. Initial evaluations were made in 1996, and the experiment was repeated in 1997. In 1998, six of the taxa were evaluated for a third year. For most of the taxa evaluated, growth was superior on ER medium. On WPM, many of the cultures browned and died. R. canescens, R. viscosum, R. prunifolium, and R. austrinum are examples of species that preferred ER medium. R. alabamense, R. arborescens, and `My Mary' performed similarly on either medium.


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