Phenotypic and genomics-assisted breeding of soybean for Central Europe : from environmental adaptation to tofu traits

Soybean (Glycine max Merr.) is one of the major crops in the world providing an important source of protein and oil for food and feed; however it is still a minor crop in Central Europe. Soybean cultivation can play an important role in a more sustainable agricultural system by increasing local and regional protein production in Europe. The demand for locally produced soybean products is still growing in Europe. The key for a successful establishment of soybean cultivation in Europe is adaptation of soybean varieties to the Central European growing conditions. For the latitudinal adaptation to long-day conditions in Central to Northern Europe, an adapted early flowering and maturity time is of crucial importance for a profitable cultivation. The key traits flowering and maturity are quantitatively inherited and mainly affected by photoperiod responsiveness and temperature sensitivity. The most important loci for an early flowering and maturity are E1-E4 and the various allelic combinations condition soybean flowering and maturity time and therefore strongly contribute to the wide adaptability (Jiang et al., 2014; Tsubokura et al., 2014; M. Xu et al., 2013). Besides the main usage as protein source for animal feeding, soybean is also a very valuable source for human consumption. Tofu is enjoying ever greater popularity in Europe, as it is one of the best sources of plant protein with additional health benefits, rich in essential amino acids, beneficial lipids, vitamins, and minerals, as well as other bioactive compounds, such as isoflavones, soyasaponin, and others, (Lima et al., 2017; Zhang et al., 2018). Thus, plant breeding has to provide not only well-adapted varieties with good agronomic and quality properties, but also provide varieties well-suited to the further processing into soymilk and tofu. Therefore, a good knowledge about the breeding target, how to assess it and how it is inherited is crucial. The conducted studies covered a broad range of aspects relevant to improve a soybean breeding program. By combining environmental analysis, E-gene analysis, genomic approaches (QTL mapping and genomic prediction), and tofu phenotyping, breeder decisions become more accurate and targeted in the way of selection thereby increasing the genetic gain. In addition, combining the results of the different aspects helps to optimize the resources of a breeding program. Increasing the knowledge about the different aspects from environment to tofu QTL enables a breeder to be more precise and focused. But the more targeted and specific, the more complex a breeding program gets, which requires adequate tools to handle all the different information in a meaningful and efficient way to enable a quick and precise breeding decision.Die Sojabohne (Glycine max Merr.) ist eine der wichtigsten Nutzpflanzen der Welt und stellt eine wichtige Protein- und Ölquelle für Lebens- und Futtermittel dar; in Mitteleuropa spielt die Sojabohne jedoch immer noch eine untergeordnete Rolle im Anbau. Der Sojabohnenanbau kann eine wichtige Rolle in einem nachhaltigeren Agrarsystem spielen, indem er die lokale und regionale Proteinproduktion in Europa steigert. Die Nachfrage nach lokal produzierten Sojabohnenprodukten wächst in Europa weiter. Der Schlüssel für eine erfolgreiche Etablierung des Sojaanbaus in Europa ist die Anpassung der Sojasorten an die mitteleuropäischen Anbaubedingungen. Für die Breitenanpassung an Langtagbedingungen in Mittel- bis Nordeuropa ist eine angepasste frühe Blüte- und Reifezeit von entscheidender Bedeutung für einen ertragreichen Anbau. Die Schlüsselmerkmale Blüte und Reife werden quantitativ vererbt und hauptsächlich durch die Photoperioden- und Temperaturempfindlichkeit beeinflusst. Die wichtigsten Genorte für eine frühe Blüte und Reife sind E1-E4. Die verschiedenen Allelkombinationen bedingen die Sojabohnenblüte und Reifezeit und tragen daher stark zur breiten Anpassungsfähigkeit bei (Jiang et al., 2014; Tsubokura et al., 2014; M. Xu et al., 2013). Neben der Hauptverwendung als Proteinquelle für die Tierfütterung ist Soja auch eine sehr wertvolle Quelle für die menschliche Ernährung. Lebensmittel auf Sojabasis spielen eine zentrale Rolle in der asiatischen Küche, die sehr unterschiedliche Produkte anbietet, wobei Tofu das wichtigste Produkt ist. Tofu erfreut sich in Europa immer größerer Beliebtheit, da er eine der besten pflanzlichen Proteinquellen mit zusätzlichem Gesundheitsnutzen ist, reich an essentiellen Aminosäuren, nützlichen Lipiden, Vitaminen und Mineralstoffen sowie anderen bioaktiven Verbindungen wie Isoflavonen, Sojasaponin und andere (Lima et al., 2017; Zhang et al., 2018). Daher muss die Pflanzenzüchtung nicht nur gut angepasste Sorten mit guten agronomischen und qualitativen Eigenschaften liefern, sondern auch Sorten, die sich für die Weiterverarbeitung zu Sojamilch und Tofu gut eignen. Gute Kenntnisse über das Zuchtziel, wie es zu beurteilen ist und wie es vererbt wird, sind daher entscheidend. Die durchgeführten Studien deckten ein breites Spektrum von Aspekten ab, die für die Verbesserung eines Sojabohnenzuchtprogramms relevant sind. Durch die Kombination von Umweltanalyse, E-Gen-Analyse, genomischen Ansätzen (QTL-Mapping und genomische Vorhersage) und Tofuphänotypisierung werden Züchterentscheidungen genauer und zielgerichteter in der Selektion, wodurch der Zuchtfortschritt erhöht wird. Darüber hinaus hilft die Kombination der Ergebnisse der verschiedenen Aspekte, die Ressourcen eines Zuchtprogramms zu optimieren. Die Erweiterung des Wissensstands über die verschiedenen Aspekte von der Umwelt bis zum Tofu-QTL ermöglicht es einem Züchter, präziser und fokussierter zu sein. Doch je gezielter und spezifischer, desto komplexer wird ein Zuchtprogramm, das adäquate Werkzeuge benötigt, um mit all den unterschiedlichen Informationen sinnvoll und effizient umzugehen, um damit dann eine schnelle und präzise Zuchtentscheidung zu ermöglichen

An accurate measurement of electron beam induced displacement cross sections for single-layer graphene

We present an accurate measurement and a quantitative analysis of electron-beam induced displacements of carbon atoms in single-layer graphene. We directly measure the atomic displacement ("knock-on") cross section by counting the lost atoms as a function of the electron beam energy and applied dose. Further, we separate knock-on damage (originating from the collision of the beam electrons with the nucleus of the target atom) from other radiation damage mechanisms (e.g. ionization damage or chemical etching) by the comparison of ordinary (12C) and heavy (13C) graphene. Our analysis shows that a static lattice approximation is not sufficient to describe knock-on damage in this material, while a very good agreement between calculated and experimental cross sections is obtained if lattice vibrations are taken into account.Comment: 10 pages including supplementary inf

Effect of the disorder in graphene grain boundaries: A wave packet dynamics study

Chemical vapor deposition (CVD) on Cu foil is one of the most promising methods to produce graphene samples despite of introducing numerous grain boundaries into the perfect graphene lattice. A rich variety of GB structures can be realized experimentally by controlling the parameters in the CVD method. Grain boundaries contain non-hexagonal carbon rings (4, 5, 7, 8 membered rings) and vacancies in various ratios and arrangements. Using wave packet dynamic (WPD) simulations and tight-binding electronic structure calculations, we have studied the effect of the structure of GBs on the transport properties. Three model GBs with increasing disorder were created in the computer: a periodic 5-7 GB, a "serpentine" GB, and a disordered GB containing 4, 8 membered rings and vacancies. It was found that for small energies (E = EF ± 1 eV) the transmission decreases with increasing disorder. Four membered rings and vacancies are identified as the principal scattering centers. Revealing the connection between the properties of GBs and the CVD growth method may open new opportunities in the graphene based nanoelectronics. © 2013 Elsevier B.V. All rights reserved

Electron beam controlled covalent attachment of small organic molecules to graphene

Markevich A, Kurasch S, Lehtinen O, et al. Electron beam controlled covalent attachment of small organic molecules to graphene. NANOSCALE. 2016;8(5):2711-2719.The electron beam induced functionalization of graphene through the formation of covalent bonds between free radicals of polyaromatic molecules and C=C bonds of pristine graphene surface has been explored using first principles calculations and high-resolution transmission electron microscopy. We show that the energetically strongest attachment of the radicals occurs along the armchair direction in graphene to carbon atoms residing in different graphene sub-lattices. The radicals tend to assume vertical position on graphene substrate irrespective of direction of the bonding and the initial configuration. The "standing up" molecules, covalently anchored to graphene, exhibit two types of oscillatory motion bending and twisting - caused by the presence of acoustic phonons in graphene and dispersion attraction to the substrate. The theoretically derived mechanisms are confirmed by near atomic resolution imaging of individual perchlorocoronene (C24Cl12) molecules on graphene. Our results facilitate the understanding of controlled functionalization of graphene employing electron irradiation as well as mechanisms of attachment of impurities via the processing of graphene nanoelectronic devices by electron beam lithography

Electronic states of disordered grain boundaries in graphene prepared by chemical vapor deposition

Perturbations of the two dimensional carbon lattice of graphene, such as grain boundaries, have significant influence on the charge transport and mechanical properties of this material. Scanning tunneling microscopy measurements presented here show that localized states near the Dirac point dominate the local density of states of grain boundaries in graphene grown by chemical vapor deposition. Such low energy states are not reproduced by theoretical models which treat the grain boundaries as periodic dislocation-cores composed of pentagonal-heptagonal carbon rings. Using ab initio calculations, we have extended this model to include disorder, by introducing vacancies into a grain boundary consisting of periodic dislocation-cores. Within the framework of this model we were able to reproduce the measured density of states features. We present evidence that grain boundaries in graphene grown on copper incorporate a significant amount of disorder in the form of two-coordinated carbon atoms. © 2013 Elsevier Ltd. All rights reserved

Atomistic dynamics of sulfur-deficient high-symmetry grain boundaries in molybdenum disulfide

As a common type of structural defect, grain boundaries (GBs) play an important role in tailoring the physical and chemical properties of bulk crystals and their two-dimensional (2D) counterparts such as graphene and molybdenum disulfide (MoS2). In this study, we explore the atomic structures and dynamics of three kinds of high-symmetry GBs (α, β and γ) in monolayer MoS2. Atomic-resolution transmission electron microscopy (TEM) is used to characterize their formation and evolutionary dynamics, and atomistic simulation based analysis explains the size distribution of α-type GBs observed under TEM and the inter-GB interaction, revealing the stabilization mechanism of GBs by pre-existing sulfur vacancies. The results elucidate the correlation between the observed GB dynamics and the migration of sulfur atoms across GBs via a vacancy-mediated mechanism, offering a new perspective for GB engineering in monolayer MoS2, which may be generalized to other transition metal dichalcogenides

Direct imaging of structural disordering and heterogeneous dynamics of fullerene molecular liquid

Structural rearrangements govern the various properties of disordered systems and visualization of these dynamical processes can provide critical information on structural deformation and phase transformation of the systems. However, direct imaging of individual atoms or molecules in a disordered state is quite challenging. Here, we prepare a model molecular system of C70 molecules on graphene and directly visualize the structural and dynamical evolution using aberration-corrected transmission electron microscopy. E-beam irradiation stimulates dynamics of fullerene molecules, which results in the first-order like structural transformation from the molecular crystal to molecular liquid. The real-time tracking of individual molecules using an automatic molecular identification process elucidates the relaxation behavior of a stretched exponential functional form. Moreover, the directly observed heterogeneous dynamics bear similarity to the dynamical heterogeneity in supercooled liquids near the glass transition. Fullerenes on graphene can serve as a new model system, which allows investigation of molecular dynamics in disordered phases