| 1. |
- Dobrowolska, Izabela, et al.
(författare)
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Histological analysis reveals the formation of shoots rather than embryos in regenerating cultures of Eucalyptus globulus
- 2017
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Ingår i: Plant Cell, Tissue and Organ Culture. - : Springer Science and Business Media LLC. - 0167-6857 .- 1573-5044. ; 128, s. 319-326
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Tidskriftsartikel (refereegranskat)abstract
- Eucalyptus globulus is an important species in international forestry in regions with Mediterranean climates and comprises 65 % of the plantation hardwood in Australia. Propagation by somatic embryogenesis would offer many advantages and its development has received much attention. Structures regenerating on explants from hypocotyls of mature zygotic embryos of E. globulus cultured on medium with NAA, reported previously to be effective for embryogenic regeneration, were analyzed morphologically and histologically to clarify their pathway of development. Analysis of series of sections revealed organogenic, rather than embryogenic, pathways of regeneration in this system. We show that protocols for propagation of E. globulus must be carefully evaluated by microscopic examination of adequate numbers of serial sections.
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| 2. |
- Liu, Meng, et al.
(författare)
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Characterization of a trichome-specific promoter of the aldehyde dehydrogenase 1 (ALDH1) gene in Artemisia annua
- 2016
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Ingår i: Plant Cell Tissue and Organ Culture. - : Springer Science and Business Media LLC. - 0167-6857 .- 1573-5044. ; 126:3, s. 469-480
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Tidskriftsartikel (refereegranskat)abstract
- Artemisinin is a frequently used anti-malaria drug extracted from glandular trichomes (GSTs) in Artemisia annua L. In this study, we report on the characterization of the promoter of aldehyde dehydrogenase 1 (ALDH1) involved in the biosynthesis of artemisinin. A 1620-bp promoter fragment was cloned upstream of the ALDH1 start codon. Putative regulatory cis-acting elements are predicted by software, revealing that this gene is affected by complex factors. The activity of the ALDH1 promoter was analyzed using a reporter gene GUS. GUS expression showed a spatial difference in leaves at different ages. In young leaves, GUS staining was exclusively discovered in GSTs. In older leaves, both GSTs and T-shaped trichomes (TSTs) showed GUS signals. Only TSTs showed GUS staining in lower leaves. No GUS staining was detected in the bottom leaves. The result demonstrates that the ALDH1 promoter is trichome-specific. The RT-Q-PCR analysis revealed that both wild-type and recombinant promoters showed similar activity in A. annua. After application of exogenous 100 μM methyl jasmonate, 100 μM gibberellin and 100 μM salicylic acid separately, the transcript levels were increased significantly, indicating that ALDH1 may play an important role in the response to hormones in A. annua.
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| 3. |
- Slazak, Blazej, et al.
(författare)
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Micropropagation of Viola uliginosa (Violaceae) for endangered species conservation and for somaclonal variation-enhanced cyclotide biosynthesis
- 2015
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Ingår i: Plant Cell Tissue and Organ Culture. - : Springer Science and Business Media LLC. - 0167-6857 .- 1573-5044. ; 120:1, s. 179-190
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Tidskriftsartikel (refereegranskat)abstract
- Viola uliginosa Besser is a European violet having its main distribution range in the Baltic Sea region. Today it is considered endangered and threatened. Species of Violaceae from different genera and sections are known to produce cyclotides, cyclic polypeptides of much interest due to their medicinal properties and chemical structure. The present study introduced a rare species of violet (V. uliginosa) to in vitro culture for biodiversity protection and as a model for cyclotide biosynthesis research in the Violaceae. Leaf and petiole fragments were cultured on MS medium solidified with agar and supplemented with different concentrations of plant growth regulators: TDZ, KIN and 2,4-D. Direct and indirect (via callus) organogenesis was induced on MS supplemented with TDZ (0.5 or 1 mg l(-1)) or with equal concentrations (2 mg l(-1)) of KIN and 2,4-D, followed by callus transfer on 1 mg l(-1) TDZ. Shoots were rooted on MS with 2 % sucrose and 0.5 mg l(-1) IBA and acclimatized. AFLP marker polymorphism was low but flow cytometry revealed that a large share of the obtained regenerants were tetraploid (2C = 4x = 2.7-2.8 pg), unlike the maternal diploid plants (2C = 2x = 1.4 pg). Eleven different cyclotides were distinguished in the aerial parts of maternal plants. Cyclotide production was significantly higher in tetraploid than in diploid plants regenerated in vitro.
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| 4. |
- Viljamaa, Sonja
(författare)
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Cryopreservation of the Norway spruce tissue culture line able to produce extracellular lignin
- 2018
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Ingår i: Plant Cell, Tissue and Organ Culture. - : Springer Science and Business Media LLC. - 0167-6857 .- 1573-5044. ; 133, s. 225-235
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Tidskriftsartikel (refereegranskat)abstract
- A cryopreservation method was developed for a Norway spruce (Picea abies L. Karst.) cell line characterised by highly vacuolated cells and ability to produce natural-like extracellular lignin in a cell suspension culture. Spruce callus cultured in a photoperiod of 16 h light, 8 h dark contained two types of callus morphologies. Soft callus was composed of loosely bound cells that dispersed into single cells and small cell aggregates when transferred into liquid medium. The callus with hard morphology had also cells that were more tightly attached to each other; this callus formed bigger cell aggregates in liquid medium in addition to single cells and small cell aggregates. The hard callus contained higher concentration of intracellular phenolic compounds as compared to soft callus. For cryopreservation, a vitrification method with plant vitrification solution 2 (PVS2) was used. To reduce cellular water content, spruce calli were pre-cultured on a culture medium with increasing sucrose concentration (0.2 and 0.4 M; one day on each). The cryopreservation survival rate of callus with hard morphology was significantly higher than that with soft morphology (45 +/- 8% and 5 +/- 5%, respectively). Pre-culturing in continuous light for several weeks led exclusively to formation of a hard-type callus, which had a survival rate of 48 +/- 16% in cryopreservation. Expression of candidate genes of the monolignol biosynthesis pathway, Fourier transform infrared spectra and pyrolysis breakdown products of extracellular lignin were similar in control cultures and those originating from cryopreserved cells suggesting that cryopreservation is a feasible method for long-term storage of the lignin-forming cell line.
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