Thunen Institute of Forest Genetics

Großhansdorf, Germany

Thunen Institute of Forest Genetics

Großhansdorf, Germany

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Luttschwager D.,Leibniz Center for Agricultural Landscape Research | Ewald D.,Thunen Institute of Forest Genetics | Atanet Alia L.,Leibniz Center for Agricultural Landscape Research
Acta Physiologiae Plantarum | Year: 2015

The establishment of short-rotation poplar plantations for the sustainable production of raw material and energy is often limited by low precipitation and poor soil conditions. Breeding research must therefore focus on combining performance with drought tolerance. Eight poplar clones were generated by tissue culture. Three times during seasonal development, photosynthesis and transpiration were measured in fully developed leaves under controlled conditions in a climate chamber. Light response curves were modelled based on these data. The efficiency of water use was analysed for all clones under well-watered conditions, and partly significant differences were observed with regard to intrinsic water use efficiency (WUE). Moreover, at the end of the season, the plants were considerably different in their biometrics, particularly in the shoot–root relationship, which might substantially influence drought resistance. A general ranking of the performance of the clones is difficult because certain physiological parameters turn over during the course of the season. However, certain “strategies” that could be divided into “generalist” and “specialist” stand out for individual clones. The aspen clone Großdubrau 1 (“specialist”) showed the maximum height, the greatest seasonal differences in WUE and the most weakly developed root system. By contrast, the poplar clone Max 2 (“generalist”) had the lowest height increase but a well-developed root system and lower volatility in WUE. Thus, drought tolerance under stress conditions may exhibit a degree of predictability. Therefore, a dry stress experiment is planned to test the two contrasting clones. © 2015, Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków.

Kersten B.,Thunen Institute of Forest Genetics | Ghirardo A.,Helmholtz Center Munich | Schnitzler J.-P.,Helmholtz Center Munich | Kanawati B.,Helmholtz Center Munich | And 3 more authors.
BMC Genomics | Year: 2013

Background: The interaction between insect pests and their host plants is a never-ending race of evolutionary adaption. Plants have developed an armament against insect herbivore attacks, and attackers continuously learn how to address it. Using a combined transcriptomic and metabolomic approach, we investigated the molecular and biochemical differences between Quercus robur L. trees that resisted (defined as resistant oak type) or were susceptible (defined as susceptible oak type) to infestation by the major oak pest, Tortrix viridana L.Results: Next generation RNA sequencing revealed hundreds of genes that exhibited constitutive and/or inducible differential expression in the resistant oak compared to the susceptible oak. Distinct differences were found in the transcript levels and the metabolic content with regard to tannins, flavonoids, and terpenoids, which are compounds involved in the defence against insect pests. The results of our transcriptomic and metabolomic analyses are in agreement with those of a previous study in which we showed that female moths prefer susceptible oaks due to their specific profile of herbivore-induced volatiles. These data therefore define two oak genotypes that clearly differ on the transcriptomic and metabolomic levels, as reflected by their specific defensive compound profiles.Conclusions: We conclude that the resistant oak type seem to prefer a strategy of constitutive defence responses in contrast to more induced defence responses of the susceptible oaks triggered by feeding. These results pave the way for the development of biomarkers for an early determination of potentially green oak leaf roller-resistant genotypes in natural pedunculate oak populations in Europe. © 2013 Kersten et al.; licensee BioMed Central Ltd.

PubMed | Thunen Institute of Forest Genetics and University of Gottingen
Type: | Journal: Forensic science international. Genetics | Year: 2017

During the past decade, the use of DNA for forensic applications has been extensively implemented for plant and animal species, as well as in humans. Tracing back the geographical origin of an individual usually requires genetic assignment analysis. These approaches are based on reference samples that are grouped into populations or other aggregates and intend to identify the most likely group of origin. Often this grouping does not have a biological but rather a historical or political justification, such as country of origin. In this paper, we present a new nearest neighbour approach to individual assignment or classification within a given but potentially imperfect grouping of reference samples. This method, which is based on the genetic distance between individuals, functions better in many cases than commonly used methods. We demonstrate the operation of our assignment method using two data sets. One set is simulated for a large number of trees distributed in a 120km by 120km landscape with individual genotypes at 150 SNPs, and the other set comprises experimental data of 1221 individuals of the African tropical tree species Entandrophragma cylindricum (Sapelli) genotyped at 61 SNPs. Judging by the level of correct self-assignment, our approach outperformed the commonly used frequency and Bayesian approaches by 15% for the simulated data set and by 5-7% for the Sapelli data set. Our new approach is less sensitive to overlapping sources of genetic differentiation, such as genetic differences among closely-related species, phylogeographic lineages and isolation by distance, and thus operates better even for suboptimal grouping of individuals.

Taeger S.,TU Munich | Zang C.,TU Munich | Liesebach M.,Thunen Institute of Forest Genetics | Schneck V.,Thunen Institute of Forest Genetics | Menzel A.,TU Munich
Forest Ecology and Management | Year: 2013

We explored the growth response of Scots pine to temperature, precipitation, and drought focusing on eleven provenances from the IUFRO 1982 international provenance trial. At two macroclimatically different sites in Germany we measured chronologies of tree-ring widths and annual height increment. We estimated general climate/growth relationships and examined the growth response, based on tolerance indices of resistance, recovery, resilience and relative resilience, to the most severe drought event per site. Using multivariate benchmarking of provenance archetypes, we established a ranking of the individual provenances in terms of general performance. In addition to considerable differences in overall growth between provenances, growth metrics differed between sites which were mostly attributable to climate. Basal area increment depended mainly on water availability from May to July, whereas annual height growth was influenced by moisture deficit during May of the current year.The reaction to drought events was shown to depend on the timing and duration of the drought event. Differences between provenances in resistance were modest, but more pronounced for recovery and especially for resilience and relative resilience. The results indicate a better adaptation to drought of the provenance from Bosnia Herzegovina and of local German provenances compared to other provenances. We summarized the findings by aligning the eleven provenances between two multivariately defined archetypes, one of which represented best general performance defined by good overall growth, low climate sensitivity and high resilience to drought. This approach confirmed the superior performance of the local German populations. Provenances from France and Poland were ranked above average whereas northern provenances and that from Bosnia Herzegovina were found to be least suitable at the sites under investigation. Our results clearly demonstrate the importance of considering provenance in the discussion about future adaptedness and adaptability of tree species under climate change scenarios. © 2013.

Schroeder H.,Thunen Institute of Forest Genetics | Fladung M.,Thunen Institute of Forest Genetics
IForest | Year: 2015

About 30 species within the genus Populus are classified in six sections. Several species belonging to different sections are cross-compatible, resulting in a high number of naturally occurring interspecific hybrids. Additionally, an even higher number of hybrids has been produced in huge breeding programs during the last 100 years. Hence, determination of poplar species used for the production of “multi-species-hybrids” is often difficult, and a challenge for the development of molecular markers aimed at species identification. Moreover, 14 of the 30 poplar species known are often used for the production of artificial hybrids and clones. In this study, over 20 regions of the chloroplast genome of poplars were analyzed by the use of 23 primer combinations already established for “barcoding” purposes, and 17 new primer combinations previously designed, with the aim of testing their suitability to differentiate 14 poplar species. Only about half of the established barcoding primer combinations yielded PCR amplification products, while new primer combinations had a much higher amplification success. Species-specific SNPs or Indels were detected in 11 out of the 14 poplar species analyzed. In order to set up a low-cost and fast method for species identification, we developed PCR-RFLPs applicable to seven of the species-specific SNPs. Overall, a high variability was found in the chloroplast intergenic spacers, as much as four primer combinations were needed to differentiate 11 species. Based on our results, the use of multi-locus combinations is recommended in barcoding analyses. © SISEF.

Pakull B.,Thunen Institute of Forest Genetics | Kersten B.,Thunen Institute of Forest Genetics | Luneburg J.,Thunen Institute of Forest Genetics | Fladung M.,Thunen Institute of Forest Genetics
Plant Biology | Year: 2015

The genus Populus features a genetically controlled sex determination system, located on chromosome 19. However, different Populus species vary in the position of the sex-linked region on the respective chromosome and the apparent heterogametic sex, and the precise mechanism of sex determination in Populus is still unknown. Using next generation sequencing of pooled samples of male and female aspens, we identified the aspen homologue of the P. trichocarpa gene Potri.019G047300 ('TOZ19') to be male-specific. While in P. tremuloides, the complete gene is missing in the genome of female plants, a short fragment of the 3′-part of the gene is still present in P. tremula females. The male-specific presence and transcription of TOZ19 was further verified using PCR in various different aspen individuals and RT-PCR expression analysis. TOZ19 is potentially involved in early steps of flower development, and represents an interesting candidate gene for involvement in sex determination in aspen. Regardless of its role as candidate gene, TOZ19 represents an ideal marker for determination of the sex of non-flowering aspen individuals or seedlings. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

Ahuja M.R.,Thunen Institute of Forest Genetics | Fladung M.,Thunen Institute of Forest Genetics
Tree Genetics and Genomes | Year: 2014

Transgene integration and inheritance have been investigated in a number of crop plants and few tree species. Transgene integration is predominantly a random process, whether mediated by Agrobacterium or particle bombardment. Depending on the genomic position of the integrated transgene and structure of the integration site as well as copy number of the transgene in the genome, its expression may be stable or variable. Therefore, integration patterns would affect the mode of transgene inheritance in plants, regardless of the method of gene transfer. So far, both Mendelian and non-Mendelian inheritance of transgenes has been reported across several generations (T1-T3) of crop plants. In few tree species (apple, poplar, plum, and American chestnut), mostly Mendelian inheritance of the transgenes has been observed in the T1 or BC1 generations. However, detailed studies in the transgenic papaya trees showed Mendelian segregation of the transgene in the T1 generation but non-Mendelian inheritance in the T2 generation. Variation in transgene inheritance was also detected in transgenic apple and plum trees. Long generation cycles in many economically important tree species preclude investigation of inheritance of transgenes in the tree progeny. Production of early flowering trees, either by genetic modification or by environmental modulation, would facilitate the study of transgene inheritance across generations of transgenic trees. In order to overcome problems of randomness of transgene integration, targeted transgene insertions by homologous or site-specific recombination or by designer recombinases or nucleases offer prospects for stable integration of transgenes in predetermined locations in the plant genome. And perhaps, that might provide a platform for stable expression and Mendelian inheritance of transgenes in plants. © 2014 Springer-Verlag Berlin Heidelberg.

Ewald D.,Thunen Institute of Forest Genetics | Naujoks G.,Thunen Institute of Forest Genetics
Dendrobiology | Year: 2015

Over the last 15 years, shoot material from wavy grain sycamore maples (Acer pseudoplatanus L.) was collected from crowns of trees which were harvested and the stems then sold for very high values. Starting with grafts from this material, cutting propagation was tested and a tissue culture method was elaborated. However, the question of whether the wavy grain structure is expressed after vegetative propagation still remained unsolved. Recently, one of the oldest cuttings (11 years) and two grafts (17 years) were cut to look for structures of wavy grain expression. Veneer was produced from the log of the cutting- derived tree. Staining experiments were carried out using veneer sheets to improve the appearance of the structures. Based on these experiments, and in using morphological comparisons with veneer from adult wavy grain sycamore, we present the first evidence for the appearance of undulating fibre structures and the beginnings of wavy grain formation even in material at around ten years of age. A hypothesis related to the formation of wavy grain in deciduous trees is discussed. © 2015, Polska Akademia Nauk. All rights reserved.

Blanc-Jolivet C.,Thunen Institute of Forest Genetics | Degen B.,Thunen Institute of Forest Genetics
Tree Genetics and Genomes | Year: 2014

Conservation of forest genetic resources has drawn much attention in the last decades, as it prevents negative effects of genetic erosion on adaptability potential of material used for afforestation. According to the German Act on Forest Reproductive Material, seed harvesting must occur in certified stands. Seed lots must stem from a minimum number of seed-trees, although the effect of this limit on genetic diversity has not been addressed. In this study, we aimed at understanding the effect of seed harvesting strategies on genetic diversity. We used the simulation model Eco-Gene and real molecular data to disentangle the effects of number of seed-trees and harvesting method in three wild cherry (Prunus avium) stands. Our results outline the importance of harvesting genetically different or distant seed-trees in maintaining genetic diversity. Besides optimal sampling strategy, we also recommend minimum harvesting of 25 seed-trees to reach 90 % of genetic diversity available within the stand. The outcomes of these results for the practice are also discussed. © 2014 Springer-Verlag Berlin Heidelberg.

Liesebach H.,Thunen Institute of Forest Genetics | Schneck V.,Thunen Institute of Forest Genetics
Silvae Genetica | Year: 2012

Black locust (Robinia pseudoacacia L.), native in mountainous regions in USA, is increasing in importance for forestry in many countries as a "multi-purpose tree" associated with breeding efforts at the family and clonal levels. A few population genetic studies exist with nuclear, codominantly inherited markers. Here we present an additional marker type, the maternally inherited chloroplast haplotypes. The studied material included samples from the natural range and from artificial stands from three European countries as well as samples from a clone collection. Eleven haplotypes belonging to two clearly separated groups of related haplotypes were found using the PCR-RFLP method. The variation pattern of chloroplast haplotypes in artificial stands is strongly influenced by the local silvicultural management.

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