Special Issue "Application of Biotechnology Techniques on Tree Species"

A special issue of Forests (ISSN 1999-4907). This special issue belongs to the section "Genetics and Molecular Biology".

Deadline for manuscript submissions: closed (25 February 2022) | Viewed by 17146

Special Issue Editors

Dr. Jorge Canhoto
E-Mail Website
Guest Editor
Department of Life Sciences, Centre for Functional Ecology, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal
Interests: plant breeding; plant biotechnology; in vitro culture; genomics; plant anatomy; somatic embryogenesisinterests; plant development; forestry
Special Issues, Collections and Topics in MDPI journals
Dr. Paloma Moncaleán
E-Mail Website
Guest Editor
Dr. Sandra Correia
E-Mail Website
Guest Editor
Department of Life Sciences, Centre for Functional Ecology, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal
Interests: plant biotechnology; plant molecular biology; plant stress biology; proteomics; transcriptomics
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Trees are dominant species in many land ecosystems and their economic relevance is well known, not only for the production of wood and other products, but also because they deliver a variety of ecosystem services, including temperature regulation, mitigation of soil erosion, and managing and filtering rainwater, and are habitats for other organisms. Due to their long reproductive and life cycles, trees require specific strategies for breeding and large-scale propagation. In recent years, biotechnology is assuming an increasingly important role in tree breeding and cloning, through the application of techniques such as somatic embryogenesis, propagation in bioreactors, genetic transformation, proteomics, genomics, and production of synthetic seeds, among many others. Based on these tools, improved trees displaying new features are now in the field assuring higher productivities and helping to preserve natural forests while contributing to fix CO2 and to avoid desertification, both from an ecological and human perspective. This Special Issue will keep researchers and other stakeholders on the cutting edge of the latest developments in the field of tree biotechnology. Those interested in tree biotechnology are welcome to collaborate and share their more recent results in this field.

Prof. Dr. Jorge Canhoto
Dr. Paloma Moncaleán
Dr. Sandra Correia
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Forests is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • acclimatization
  • bioreactors
  • breeding
  • cloning
  • genetic transformation
  • in vitro
  • molecular biology
  • omics
  • rooting

Published Papers (11 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Article
Somatic Embryogenesis of Pinus sylvestris L. from Parent Genotypes with High- and Low Stilbene Content in Their Heartwood
Forests 2022, 13(4), 557; https://doi.org/10.3390/f13040557 - 31 Mar 2022
Viewed by 1162
Abstract
The increasing concern about ecological impacts of wood preservation chemicals has raised the interest in the natural durability of Scots pine (Pinus sylvestris L.) heartwood. Phenolic compounds—stilbenes—have been found to inhibit fungal growth, making heartwood more resistant to decay. There is a [...] Read more.
The increasing concern about ecological impacts of wood preservation chemicals has raised the interest in the natural durability of Scots pine (Pinus sylvestris L.) heartwood. Phenolic compounds—stilbenes—have been found to inhibit fungal growth, making heartwood more resistant to decay. There is a strong genetic component in the stilbene content of the heartwood in Scots pine, with a positive correlation between stilbene content in the heartwood of mother trees and their progenies. Vegetative propagation, i.e., somatic embryogenesis (SE) of Scots pine genotypes with high content of stilbenes could provide a way to produce more durable timber, assuming that there is no trade-off between SE propagation and capacity for high stilbene synthesis. To study this, we made SE initiations from parent genotypes with high and low content of stilbenes in their heartwood, using seed embryos from both open-pollinations and controlled crossings as explants. The success of SE was followed from initiation to embling acclimatization, together with measurements of stilbene content in the explants and the established SE lines. The results show that SE can be induced and emblings regenerated from trees with both high and low content of stilbene. Content of stilbenes was generally low in SE cultures and varied widely among the lines. Following the successful initiation, the later phases of SE propagation proceeded with no connection to the parent genotypes or the stilbene level of the ECs and had large variation among SE-lines. Full article
(This article belongs to the Special Issue Application of Biotechnology Techniques on Tree Species)
Show Figures

Graphical abstract

Article
Variation of Morphological Traits and Quality Indices of Micropropagated Melia volkensii Gürke Clones before Field Planting
Forests 2022, 13(2), 337; https://doi.org/10.3390/f13020337 - 18 Feb 2022
Cited by 1 | Viewed by 1587
Abstract
The quality of acclimatized in vitro cultivated plants is essential to ensure good survival and growth after planting in field conditions. After two months of acclimatization, this study revealed a significant variation in survival rate, shoot characteristics, root traits, and biomass features between [...] Read more.
The quality of acclimatized in vitro cultivated plants is essential to ensure good survival and growth after planting in field conditions. After two months of acclimatization, this study revealed a significant variation in survival rate, shoot characteristics, root traits, and biomass features between 13 clones of Melia volkensii Gürke. A number of quality indices such as the Dickson Quality Index (DQI), shoot dry weight: root dry weight ratio (S:R), and sturdiness quotient (SQ) also showed a large variation. The survival rate was genotype-dependent, with an average of 85%. Extreme genotypes were tall, had long internodes, a lot of leaves, and a large leaf area. At the other side of the spectrum, there were small clones with short internodes and a reduced number of leaves and leaf areas. The high S:R values (>2) of the evaluated clones indicate an imbalance between the shoot and root system, negatively influencing the quality of the in vitro produced M. volkensii plants. The SQ for all clones was below the threshold value of 6, implying a good and expected survival rate. This study illustrates that some clones might systematically score better for SQ, S:R, plant volume, and DQI after acclimatization and that these factors could form the basis for selection. Full article
(This article belongs to the Special Issue Application of Biotechnology Techniques on Tree Species)
Show Figures

Figure 1

Article
Differences in Environmental and Hormonal Regulation of Growth Responses in Two Highly Productive Hybrid Populus Genotypes
Forests 2022, 13(2), 183; https://doi.org/10.3390/f13020183 - 26 Jan 2022
Viewed by 1366
Abstract
Phenotypic plasticity, in response to adverse conditions, determines plant productivity and survival. The aim of this study was to test if two highly productive Populus genotypes, characterised by different in vitro etiolation patterns, differ also in their responses to hormones gibberellin (GA) and [...] Read more.
Phenotypic plasticity, in response to adverse conditions, determines plant productivity and survival. The aim of this study was to test if two highly productive Populus genotypes, characterised by different in vitro etiolation patterns, differ also in their responses to hormones gibberellin (GA) and abscisic acid (ABA), and to a GA biosynthesis inhibitor paclobutrazol (PBZ). The experiments on shoot cultures of ‘Hybrida 275′ (abbr. H275; Populus maximowiczii × P. trichocarpa) and IBL 91/78 (Populus tremula × P. alba) were conducted by either modulating the physical in vitro environment or by adding specific chemicals to the nutrient medium. Our results revealed two main sets of differences between the studied genotypes in environmental and hormonal regulation of growth responses. First, the genotype H275 responded to darkness with PBZ-inhibitable shoot elongation; in contrast, the elongation of IBL 91/78 shoots was not affected either by darkness or PBZ treatment. Secondly, the explants of H275 were unable to recover their growth if it was inhibited with ABA; in contrast, those of IBL 91/78 recovered so well after the temporal inhibition by ABA that, when rooted subsequently, they developed longer shoots and roots than without a previous ABA treatment. Our results indicate that GA catabolism and repressive signalling provide an important pathway to control growth and physiological adaptation in response to immediate or impending adverse conditions. These observations can help breeders define robust criteria for identifying genotypes with high resistance and productivity and highlight where genotypes exhibit susceptibility to stress. Full article
(This article belongs to the Special Issue Application of Biotechnology Techniques on Tree Species)
Show Figures

Figure 1

Article
Micropropagation, Characterization, and Conservation of Phytophthora cinnamomi-Tolerant Holm Oak Mature Trees
Forests 2021, 12(12), 1634; https://doi.org/10.3390/f12121634 - 25 Nov 2021
Cited by 7 | Viewed by 1174
Abstract
Holm oak populations have deteriorated drastically due to oak decline syndrome. The first objective of the present study was to investigate the use of axillary budding and somatic embryogenesis (SE) to propagate asymptomatic holm oak genotypes identified in disease hotspots in Spain. Axillary [...] Read more.
Holm oak populations have deteriorated drastically due to oak decline syndrome. The first objective of the present study was to investigate the use of axillary budding and somatic embryogenesis (SE) to propagate asymptomatic holm oak genotypes identified in disease hotspots in Spain. Axillary budding was achieved in two out of six tolerant genotypes from the south-western region and in two out of four genotypes from the Mediterranean region. Rooting of shoots cultured on medium supplemented with 3 mg L−1 of indole-3-acetic acid plus 0.1 mg L−1 α-naphthalene acetic acid was achieved, with rates ranging from 8 to 36%. Shoot cultures remained viable after cold storage for 9–12 months; this procedure is therefore suitable for medium-term conservation of holm oak germplasm. SE was induced in two out of the three genotypes tested, by using nodes and shoot tips cultured in medium without plant growth regulators. In vitro cloned progenies of the tolerant genotypes PL-T2 and VA5 inhibited growth of Phytophthora cinnamomi mycelia when exposed to the oomycete in vitro. Significant differences in total phenol contents and in the expression profiles of genes regulating phenylpropanoid biosynthesis were observed between in vitro cultured shoots derived from tolerant trees and cultures established from control genotypes. Full article
(This article belongs to the Special Issue Application of Biotechnology Techniques on Tree Species)
Show Figures

Figure 1

Article
Plant Regeneration and In Vitro Growth Performance of Male-Sterile Somatic Plantlets of Sugi (Japanese Cedar, Cryptomeria japonica) Derived from Different Embryogenic Cell Lines
Forests 2021, 12(11), 1592; https://doi.org/10.3390/f12111592 - 18 Nov 2021
Cited by 1 | Viewed by 1090
Abstract
With the spread of pollinosis caused by sugi (Japanese cedar, Cryptomeria japonica) pollen, the use of pollen-free somatic seedlings of sugi is expected in Japan. However, there is a lack of knowledge on the relationship between the abilities during somatic embryogenesis, initial [...] Read more.
With the spread of pollinosis caused by sugi (Japanese cedar, Cryptomeria japonica) pollen, the use of pollen-free somatic seedlings of sugi is expected in Japan. However, there is a lack of knowledge on the relationship between the abilities during somatic embryogenesis, initial in vitro growth traits, and subsequent growth of somatic seedlings. In the present study, we provide the first basic information on somatic embryo maturation efficiency, somatic embryo germination, and plantlet conversion frequencies, as well as on in vitro growth performance of pollen-free somatic plantlets derived from different embryogenic cell lines (ECLs). Somatic embryo maturation efficiency varied from 34 to 514 cotyledonary embryos per plate and the average for the 19 ECLs tested was 244 embryos per plate. Subsequently, the overall average rates of somatic embryo germination and conversion among ECLs were 87.8% and 85.3%, respectively. The results of in vitro growth performance of pollen-free somatic plantlets showed significant differences in growth rate among ECLs. Full article
(This article belongs to the Special Issue Application of Biotechnology Techniques on Tree Species)
Show Figures

Graphical abstract

Article
The Effect of Sucrose Supplementation on the Micropropagation of Salix viminalis L. Shoots in Semisolid Medium and Temporary Immersion Bioreactors
Forests 2021, 12(10), 1408; https://doi.org/10.3390/f12101408 - 15 Oct 2021
Cited by 5 | Viewed by 1120
Abstract
The effect of sucrose concentration on the micropropagation of axillary shoots of willow was investigated. The following factors were examined: the culture system (semisolid medium in glass jars versus liquid medium in temporary immersion bioreactors), the type of explant (apical and basal sections), [...] Read more.
The effect of sucrose concentration on the micropropagation of axillary shoots of willow was investigated. The following factors were examined: the culture system (semisolid medium in glass jars versus liquid medium in temporary immersion bioreactors), the type of explant (apical and basal sections), the frequency of immersion, and CO2 enrichment. Shoots and leaf growth were significantly higher in RITA® bioreactors than in the jars for all the sucrose treatments. Apical or basal sections of willow cultured in bioreactors under high light intensity (150 µmol m−2 s−1) and ventilated six times a day with CO2-enriched air were successfully proliferated without sucrose, whereas shoots cultured in jars did not proliferate well if sucrose concentration was 0.5% or lower. More roots were formed when sucrose was added to the medium. Shoots cultured in bioreactors were successfully acclimatized irrespective of the sucrose treatment and the root biomass when transferred to ex vitro conditions. This is the first report of photoautotrophic willow micropropagation, our results confirm the importance of proper gaseous exchange to attain autotrophy during in vitro propagation. Full article
(This article belongs to the Special Issue Application of Biotechnology Techniques on Tree Species)
Show Figures

Graphical abstract

Article
Explant, Medium, and Plant Growth Regulator (PGR) Affect Induction and Proliferation of Callus in Abies koreana
Forests 2021, 12(10), 1388; https://doi.org/10.3390/f12101388 - 11 Oct 2021
Cited by 3 | Viewed by 1211
Abstract
Korean fir (Abies koreana E.H. Wilson) is a unique Pinaceae tree species endemic in Korea. In recent years, it is believed that climate change has caused many of them to die. Therefore, it has become extremely important to protect and preserve this [...] Read more.
Korean fir (Abies koreana E.H. Wilson) is a unique Pinaceae tree species endemic in Korea. In recent years, it is believed that climate change has caused many of them to die. Therefore, it has become extremely important to protect and preserve this tree species. In this study, the possibility of callus induction using different explants, media, and plant growth regulators (PGRs) was studied. After the dormancy period in May 2020, needles and stem segments that grew from the leaf buds as the explants were collected from one-year-old shoots. The explants were disinfected and subsequently transferred to culture media supplemented with different combinations of auxins and cytokinins. These explants were cultured in the dark in a culture room with a 16 h photoperiod, day/night temperature of 24/18 °C, and 80% relative humidity. After 8 weeks, significant differences were observed in the callus induction and proliferation, as affected by the explant type, basic medium, and PGR. The stem segments were more suitable as the explants for callus induction than needles were. Furthermore, fluffy calli suitable for differentiating the regeneration buds were observed on the calli induced from stem segments. The Murashige and Skoog (MS) medium was the most effective of the three media used in this study, namely MS, Douglas fir cotyledon revised (DCR), and Quoirin and Lepoivre (LP) media, with the highest callus induction ratio of stem segments being 100.0%. The highest fresh callus weight was also observed on the MS medium (819.3 mg). Moreover, the PGR combinations of α-naphthaleneacetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D), and 6-benzylaminopurine (6-BA) consistently exerted a positive influence on callus induction throughout this study. In addition, the advantages of these two kinds of PGR were reflected in callus proliferation. The callus proliferation ratio reached 1147.6% as compared to the initial fresh weight, with a high concentration of 2,4-D (3.0 mg·L−1). In conclusion, the MS medium was optimal for callus induction on the stem segment explants, and 2,4-D promoted callus induction as well as an increased proliferation ratio of callus in A. koreana. Full article
(This article belongs to the Special Issue Application of Biotechnology Techniques on Tree Species)
Show Figures

Figure 1

Article
Experimental Examination of Vegetative Propagation Methods of Nothofagus antarctica (G. Forst.) Oerst. for Restoration of Fire-Damaged Forest in Torres del Paine National Park, Chile
Forests 2021, 12(9), 1238; https://doi.org/10.3390/f12091238 - 13 Sep 2021
Cited by 1 | Viewed by 1266
Abstract
Nothofagus antarctica (Antarctic beech) is one of the main woody plants in the temperate deciduous forests and anti-boreal forests of the southern hemisphere. Since colonization of the Andean-Patagonian region by European settlers, however, stands of this species have been severely affected by fires [...] Read more.
Nothofagus antarctica (Antarctic beech) is one of the main woody plants in the temperate deciduous forests and anti-boreal forests of the southern hemisphere. Since colonization of the Andean-Patagonian region by European settlers, however, stands of this species have been severely affected by fires caused by human activities, considerably reducing their area. To restore these forests to their area occupied before the fires, it is necessary to use artificial regeneration, relying on production of transplants in forest nurseries. Due to the low capacity for seed propagation, we focus on possibilities of producing seedlings by vegetative propagation. In a trial, we collected cuttings during three sets of dates, and attempted to root them using three combinations of substrate and ten combinations of stimulators. Using the most favorable combination of collection period, substrate and stimulator tested resulted in rooting of 23% of the cuttings, which exceeds the documented germination rates for this species. Full article
(This article belongs to the Special Issue Application of Biotechnology Techniques on Tree Species)
Show Figures

Graphical abstract

Article
Regeneration of Pinus halepensis (Mill.) through Organogenesis from Apical Shoot Buds
Forests 2021, 12(3), 363; https://doi.org/10.3390/f12030363 - 19 Mar 2021
Cited by 6 | Viewed by 1656
Abstract
Organogenesis and somatic embryogenesis have been widely applied as the two main regeneration pathways in plant tissue cultures. However, recalcitrance is still the main restriction in the clonal propagation of many woody species, especially in conifers. They undergo a “phase change” that leads [...] Read more.
Organogenesis and somatic embryogenesis have been widely applied as the two main regeneration pathways in plant tissue cultures. However, recalcitrance is still the main restriction in the clonal propagation of many woody species, especially in conifers. They undergo a “phase change” that leads to significant loss of vegetative propagation capacity, reducing the aptitude of tissues and organs to be regenerated in vitro beyond this point. In line with this, the in vitro regeneration of mature conifer trees has been a long-cherished goal in many laboratories worldwide. Based on previous works in Pinus species regeneration from adult trees, we now present data about the culture of apical shoot buds in an attempt to induce organogenesis and somatic embryogenesis to clone mature trees of Aleppo pine (Pinus halepensis). Reinvigorated axillary shoots were submitted to conditions usually applied to induce somatic embryogenesis through the manipulation of culture media, including the use of auxins such as 2,4-Dichlorophenoxyacetic acid and 1-Naphthaleneacetic acid, cytokinins (6-benzyladenine and kinetin), and phytosulfokine (50, 100, and 200 nM). Although somatic embryos could not be obtained, an embryogenic-like tissue was produced, followed by the emergence of actively proliferating non-embryogenic calli. Variations in the consistence, texture, and color of non-embryogenic calli were observed; especially those arising in the media containing phytosulfokine. Reinvigorated shoots, induced by 22 or 44 µM 6-benzyladenine, were obtained through organogenesis and acclimatized, and phenotypically normal plants were obtained. Full article
(This article belongs to the Special Issue Application of Biotechnology Techniques on Tree Species)
Show Figures

Figure 1

Article
Hybridization Assays in Strawberry Tree toward the Identification of Plants Displaying Increased Drought Tolerance
Forests 2021, 12(2), 148; https://doi.org/10.3390/f12020148 - 27 Jan 2021
Cited by 5 | Viewed by 1569
Abstract
Arbutus unedo L. is a small Ericaceae tree with a circum-Mediterranean distribution. It has a huge ecological impact on southern Europe forests and a great economic importance as a source of phytochemicals with bioactive properties and for fruit production. On the foreseen climate [...] Read more.
Arbutus unedo L. is a small Ericaceae tree with a circum-Mediterranean distribution. It has a huge ecological impact on southern Europe forests and a great economic importance as a source of phytochemicals with bioactive properties and for fruit production. On the foreseen climate change context, breeding toward drought tolerance is necessary in order to ameliorate plant performance. Therefore, the aim of this work was to study the reproduction mechanisms of the strawberry tree, obtain new genetic combinations by hybridization, and select genotypes more tolerant to drought stress. A morphological analysis of flowers and pollen was carried out, and controlled pollinations were performed both in vitro and ex vitro. The very first approach on strawberry tree breeding by means of hybridization is also presented. Several physiological parameters were evaluated on 26 genotypes submitted to a water-deficit regime. Plant behavior under drought greatly varied among genotypes, which showed high phenotype plasticity. Three genotypes that were able to cope with water restriction without compromising net CO2 assimilation were identified as highly tolerant to drought stress. The results obtained elucidate the reproduction mechanisms of the strawberry tree and open the way for a long-term breeding program based on the selection of drought-tolerant plants. Full article
(This article belongs to the Special Issue Application of Biotechnology Techniques on Tree Species)
Show Figures

Graphical abstract

Article
Hybrid Pine (Pinus attenuata × Pinus radiata) Somatic Embryogenesis: What Do You Prefer, Mother or Nurse?
Forests 2021, 12(1), 45; https://doi.org/10.3390/f12010045 - 31 Dec 2020
Cited by 2 | Viewed by 1674
Abstract
Development of hybrid pines of Pinus radiata D. Don for commercial forestry presents an opportunity to diversify the current resource of plant material. Climate change and different land uses pose challenges, making alternative species necessary to guarantee wood and non-wood products in the [...] Read more.
Development of hybrid pines of Pinus radiata D. Don for commercial forestry presents an opportunity to diversify the current resource of plant material. Climate change and different land uses pose challenges, making alternative species necessary to guarantee wood and non-wood products in the future. Pinus radiata var. cedrosensis × Pinus attenuata hybrid possesses different attributes, such as tolerance to drought conditions, better growth and resistance to snow damage at higher altitudes, and more importantly, different wood quality characteristics. Embryogenic cell lines were successfully initiated reciprocal hybrids using as initial explants megagametophytes, excised zygotic embryos and excised zygotic embryos plus nurse culture. However, the questions raised were: does the initiation environment affect the conversion to somatic plantlets months later? Does the mother tree or the cross have an effect on the conversion to somatic plantlets? In the present work we analysed the maturation rate, number of somatic embryos, germination rate, and the ex-vitro growth in cell lines derived from different initiation treatments, mother tree species, and crosses. Differences were not observed for in vitro parameters such as maturation and germination. However, significant differences were observed due to the mother tree species in relation with the ex-vitro growth rates observed, being higher those in which P. radiata acted as a mother. Moreover, embryogenic cell lines from these hybrids were stored at −80 °C and regenerated after one and five years. Full article
(This article belongs to the Special Issue Application of Biotechnology Techniques on Tree Species)
Show Figures

Figure 1

Back to TopTop