Modification Of Traits Research Articles

Transgenic insertion of the cyanobacterial membrane protein ictB increases grain yield in Zea mays through increased photosynthesis and carbohydrate production.

The C4 crop maize (Zea mays) is the most widely grown cereal crop worldwide and is an essential feedstock for food and bioenergy. Improving maize yield is important to achieve food security and agricultural sustainability in the 21st century. One potential means to improve crop productivity is to enhance photosynthesis. ictB, a membrane protein that is highly conserved across cyanobacteria, has been shown to improve photosynthesis, and often biomass, when introduced into diverse C3 plant species. Here, ictB from Synechococcus sp. strain PCC 7942 was inserted into maize using Agrobacterium-mediated transformation. In three controlled-environment experiments, ictB insertion increased leaf starch and sucrose content by up to 25% relative to controls. Experimental field trials in four growing seasons, spanning the Midwestern United States (Summers 2018 & 2019) and Argentina (Winter 2018 & 2019), showed an average of 3.49% grain yield improvement, by as much as 5.4% in a given season and up to 9.4% at certain trial locations. A subset of field trial locations was used to test for modification of ear traits and ФPSII, a proxy for photosynthesis. Results suggested that yield gain in transgenics could be associated with increased ФPSII, and the production of longer, thinner ears with more kernels. ictB localized primarily to the microsome fraction of leaf bundle-sheath cells, but not to chloroplasts. Extramembrane domains of ictB interacted in vitro with proteins involved in photosynthesis and carbohydrate metabolism. To our knowledge, this is the first published evidence of ictB insertion into a species using C4 photosynthesis and the largest-scale demonstration of grain yield enhancement from ictB insertion in planta. Results show that ictB is a valuable yield gene in the economically important crop maize, and are an important proof of concept that transgenic manipulation of photosynthesis can be used to create economically viable crop improvement traits.

Bidirectional plant‐mediated interactions between rhizobacteria and shoot‐feeding herbivorous insects: a community ecology perspective

Plants interact with various organisms, aboveground as well as belowground. Such interactions result in changes in plant traits with consequences for members of the plant‐associated community at different trophic levels. Research thus far focussed on interactions of plants with individual species. However, studying such interactions in a community context is needed to gain a better understanding. Members of the aboveground insect community induce defences that systemically influence plant interactions with herbivorous as well as carnivorous insects. Plant roots are associated with a community of plant‐growth promoting rhizobacteria (PGPR). This PGPR community modulates insect‐induced defences of plants. Thus, PGPR and insects interact indirectly via plant‐mediated interactions. Such plant‐mediated interactions between belowground PGPR and aboveground insects have usually been addressed unidirectionally from belowground to aboveground. Here, we take a bidirectional approach to these cross‐compartment plant‐mediated interactions. Recent studies show that upon aboveground attack by insect herbivores, plants may recruit rhizobacteria that enhance plant defence against the attackers. This rearranging of the PGPR community in the rhizosphere has consequences for members of the aboveground insect community. This review focusses on the bidirectional nature of plant‐mediated interactions between the PGPR and insect communities associated with plants, including (a) effects of beneficial rhizobacteria via modification of plant defence traits on insects and (b) effects of plant defence against insects on the PGPR community in the rhizosphere. We discuss how such knowledge can be used in the development of sustainable crop‐protection strategies.

Changes in Nkx2.1, Sox2, Bmp4, and Bmp16 expression underlying the lung-to-gas bladder evolutionary transition in ray-finned fishes.

The key to understanding the evolutionary origin and modification of phenotypic traits is revealing the responsible underlying developmental genetic mechanisms. An important organismal trait of ray-finned fishes is the gas bladder, an air-filled organ that, in most fishes, functions for buoyancy control, and is homologous to the lungs of lobe-finned fishes. The critical morphological difference between lungs and gas bladders, which otherwise share many characteristics, is the general direction of budding during development. Lungs bud ventrally and the gas bladder buds dorsally from the anterior foregut. We investigated the genetic underpinnings of this ventral-to-dorsal shift in budding direction by studying the expression patterns of known lung genes (Nkx2.1, Sox2, and Bmp4) during the development of lungs or gas bladder in three fishes: bichir, bowfin, and zebrafish. Nkx2.1 and Sox2 show reciprocal dorsoventral expression patterns during tetrapod lung development and are important regulators of lung budding; their expression during bichir lung development is conserved. Surprisingly, we find during gas bladder development, Nkx2.1 and Sox2 expression are inconsistent with the hypothesis that they regulate the direction of gas bladder budding. Bmp4 is expressed ventrally during lung development in bichir, akin to the pattern during mouse lung development. During gas bladder development, Bmp4 is not expressed. However, Bmp16, a paralogue of Bmp4, is expressed dorsally in the developing gas bladder of bowfin. Bmp16 is present in the known genomes of Actinopteri (ray-finned fishes excluding bichir) but absent from mammalian genomes. We hypothesize that Bmp16 was recruited to regulate gas bladder development in the Actinopteri in place of Bmp4.

Genome Editing for Resistance to Insect Pests: An Emerging Tool for Crop Improvement.

Plants are challenged incessantly by several biotic and abiotic stresses during their entire growth period. As with other biotic stress factors, insect pests have also posed serious concerns related to yield losses due to which agricultural productivity is at stake. In plants, trait modification for crop improvement was initiated with breeding approaches followed by genetic engineering. However, stringent regulatory policies for risk assessment and lack of social acceptance for genetically modified crops worldwide have incited researchers toward alternate strategies. Genome engineering or genome editing has emerged as a new breeding technique with the ability to edit the genomes of plants, animals, microbes, and human beings. Several gene editing strategies are being executed with continuous emergence of variants. The scientific community has unraveled the utility of various editing tools from endonucleases to CRISPR/Cas in several aspects related to plant growth, development, and mitigation of stresses. The categorical focus on the development of tools and techniques including designing of binary vectors to facilitate ease in genome engineering are being pursued. Through this Review, we embark upon the conglomeration of various genome editing strategies that can be and are being used to design insect pest resistance in plants. Case studies and novel crop-based approaches that reiterate the successful use of these tools in insects as well as in plants are highlighted. Further, the Review also provides implications for the requirement of a specific regulatory framework and risk assessment of the edited crops. Genome editing toward insect pest management is here to stay, provided uncompromising efforts are made toward the identification of amiable target genes.

The APOA5-rs662799 Polymorphism Is a Determinant of Dyslipidemia in Vietnamese Primary School Children.

Apolipoprotein A-V encoded by apolipoprotein 5 (APOA5) gene plays an important role in lipid metabolism, especially in the regulation of plasma triglycerol levels. The study aimed to evaluate the association of the APOA5-rs662799 polymorphism with dyslipidemia in Vietnamese children and the potential modification of obesity-related traits (body mass index, waist circumference, hip circumference, and waist-to-hip ratio) on this association. A case-control study was conducted with a total of 154 dyslipidemia cases and 389 controls at the age of 6 to 10 recruited at 31 primary schools in Hanoi city of Vietnam. Genotype for APOA5-rs662799 polymorphism was determined by the restriction fragment length polymorphism analysis. The association of APOA5-rs662799 polymorphism with dyslipidemia adjusting for age, sex, residence, and obesity-related traits was analyzed by binary logistic regression analysis. The results showed that in comparison with T/T and T/C carriers, the C/C carriers had a higher concentration of serum TAG in cases (p =0.049). Carriers of the C allele (C/C + T/C) had higher risk for developing dyslipidemia and hypertriglyceridemia than subjects with T/T genotype (odds ratio, OR = 1.7, p =0.0062 and OR = 1.6, p = 0.026, respectively). The association remained significant after adjusting for age, gender, residence, and obesity status (OR = 1.75, p = 0.006 and OR = 1.53, p = 0.049, respectively) or other obesity-related traits. The study suggested that the APOA5-rs662799 polymorphism may be a determinant of dyslipidemia and hypertriglyceridemia in Vietnamese children, independent of obesity-related traits.

A "Population Dynamics" Perspective on the Delayed Life-History Effects of Environmental Contaminations: An Illustration with a Preliminary Study of Cadmium Transgenerational Effects over Three Generations in the Crustacean Gammarus.

We explore the delayed consequences of parental exposure to environmentally relevant cadmium concentrations on the life-history traits throughout generations of the freshwater crustacean Gammarus fossarum. We report the preliminary results obtained during a challenging one-year laboratory experiment in this environmental species and propose the use of population modeling to interpret the changes in offspring life-history traits regarding their potential demographic impacts. The main outcome of this first long-term transgenerational assay is that the exposure of spawners during a single gametogenesis cycle (3 weeks) could result in severe cascading effects on the life-history traits along three unexposed offspring generations (one year). Indeed, we observed a decrease in F1 reproductive success, an early onset of F2 offspring puberty with reduced investment in egg yolk reserves, and finally a decrease in the growth rate of F3 juveniles. However, the analysis of these major transgenerational effects by means of a Lefkovitch matrix population model revealed only weak demographic impacts. Population compensatory processes mitigating the demographic consequences of parental exposure seem to drive the modification of life-history traits in offspring generations. This exploratory study sheds light on the role of population mechanisms involved in the demographic regulation of the delayed effects of environmental toxicity in wild populations.

Review on Somatic Hybridization and Its Role in Crop Improvement

Somatic hybridization is one of the most important uses of protoplast culture. This is particularly significant for hybridization between species or genera, which cannot be made to cross by conventional methods of sexual hybridization. The aim of somatic hybridization is to transfer traits which are desired and generate a beneficial crop plants without genetic engineering and as well as facilitate conventional breeding through providing novel crop lines. Somatic hybridization broadens the base of accessible germplasm and offers additional opportunities for introgression of desirable traits into cultivars. Plant protoplasts can be fused and the fusion products cultured to produce somatic hybrid plants. This technique has been used to produce germplasm previously unavailable to the plant breeder. Several researchers have emphasized production of hybrids between distantly related, sexually incompatible species, but many of these hybrids are sterile, precluding incorporation into a breeding program. Hence, to transfer traits such as disease and herbicide resistance, emphasis has shifted to production of hybrids between more closely related species. Novel variation has been observed in such somatic hybrids due to segregation of mixed organelles, cytoplasmic and nuclear gene recombination, and somaclonal variation. The unique gene combinations made possible by protoplast fusion ensure that new plant varieties will soon be derived from somatic hybridization. Even though measurable success of somatic hybridization in terms of cultivar release may still be limited, the potential for their use in plant breeding remains great. In general, somatic hybridization provides excellent opportunities for research on plant improvement, first by exploring genetic variations among the existing crops and then by attempting to transfer the available genetic information from one species to another through fusion of protoplasts isolated from somatic tissues of these crops. Somatic hybridization is contributing to plant breeding in overcoming common crossing barriers among plant species. Some of the problems could be overcome by somatic hybridization are: sexual incompatibility, nucellar embryogenesis, male or female sterility, transfer of resistance genes for biotic and abiotic stresses, to create novel hybrids with increased yields. Several steps are involved in the somatic hybridization process. Some of them are: identification of the source of protoplasts, isolation of protoplasts, planting of protoplasts, regeneration of plants, fusion of protoplasts, selection procedures, identification and characterization of somatic hybrid plants. Generally somatic hybridization is playing a key role in the production of novel interspecific and intergeneric hybrids and transfer of genes for diseases resistance, abiotic stress resistance, herbicide resistance and many other quality characters. Besides being of value for the transfer of unidentified genes, somatic hybridization is a tool for the modification and improvement of polygenic traits. Furthermore, the modification of organellar genetic material is possible via somatic hybridization since a mixture of the two fusion partners is obtained in the hybrid cell Production of hybrid plants through the fusion of protoplasts of two different plant species/varieties. Keywords: Somatic; Hybridization; Protoplast; Fusion. DOI: 10.7176/JBAH/10-11-04 Publication date: June 30 th 2020

Gene editing: an instrument for practical application of gene biology to plant breeding.

Plant breeding is well recognized as one of the most important means to meet food security challenges caused by the ever-increasing world population. During the past three decades, plant breeding has been empowered by both new knowledge on trait development and regulation (e.g., functional genomics) and new technologies (e.g., biotechnologies and phenomics). Gene editing, particularly by clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) and its variants, has become a powerful technology in plant research and may become a game-changer in plant breeding. Traits are conferred by coding and non-coding genes. From this perspective, we propose different editing strategies for these two types of genes. The activity of an encoded enzyme and its quantity are regulated at transcriptional and post-transcriptional, as well as translational and post-translational, levels. Different strategies are proposed to intervene to generate gene functional variations and consequently phenotype changes. For non-coding genes, trait modification could be achieved by regulating transcription of their own or target genes via gene editing. Also included is a scheme of protoplast editing to make gene editing more applicable in plant breeding. In summary, this review provides breeders with a host of options to translate gene biology into practical breeding strategies, i.e., to use gene editing as a mechanism to commercialize gene biology in plant breeding.

Growth Spectrum Complexity Dictates Aromatic Intensity in Coriander (Coriandrum sativum L.).

Advancements in availability and specificity of light-emitting diodes (LEDs) have facilitated trait modification of high-value edible herbs and vegetables through the fine manipulation of spectra. Coriander (Coriandrum sativum L.) is a culinary herb, known for its fresh, citrusy aroma, and high economic value. Studies into the impact of light intensity and spectrum on C. sativum physiology, morphology, and aroma are limited. Using a nasal impact frequency panel, a selection of key compounds associated with the characteristic aroma of coriander was identified. Significant differences (P < 0.05) were observed in the concentration of these aromatics between plants grown in a controlled environment chamber under the same photosynthetic photon flux density (PPFD) but custom spectra: red (100%), blue (100%), red + blue (RB, 50% equal contribution), or red + green + blue (RGB, 35.8% red: 26.4% green: 37.8% blue) wavelengths. In general, the concentration of aromatics increased with increasing numbers of wavelengths emitted alongside selective changes, e.g., the greatest increase in coriander-defining E-(2)-decenal occurred under the RGB spectrum. This change in aroma profile was accompanied by significant differences (P < 0.05) in light saturated photosynthetic CO2 assimilation, water-use efficiency (Wi), and morphology. While plants grown under red wavelengths achieved the greatest leaf area, RB spectrum plants were shortest and had the highest leaf:shoot ratio. Therefore, this work evidences a trade-off between sellable commercial morphologies with a weaker, less desirable aroma or a less desirable morphology with more intense coriander-like aromas. When supplemental trichromatic LEDs were used in a commercial glasshouse, the majority of compounds, with the exception of linalool, also increased showing that even as a supplement additional wavelength can modify the aromatic profile increasing its complexity. Lower levels of linalool suggest these plants may be more susceptible to biotic stress such as herbivory. Finally, the concentration of coriander-defining aromatics E-(2)-decenal and E-(2)-hexenal was significantly higher in supermarket pre-packaged coriander leaves implying that concentrations of aromatics increase after excision. In summary, spectra can be used to co-manipulate aroma profile and plant form with increasing spectral complexity leading to greater aromatic complexity and intensity. We suggest that increasing spectral complexity progressively stimulates signaling pathways giving rise to valuable economic traits.

Has Technology Increased Agricultural Yield Risk? Evidence from the Crop Insurance Biotech Endorsement

The conventional wisdom that technological advances in seed breeding and genetic modification of corn traits have lowered yield risk has recently been challenged by research that argues that the converse is true. The implications of this research have been applied to models of climate change and have led to the conclusion that these advances have actually increased agronomic risk, such that climate change is asserted to raise important concerns regarding the stability and viability of agricultural output in the future. In a large body of empirical work, the argument is based upon assertions that corn yields have become more sensitive to weather stresses. This increased sensitivity has coincided with the introduction of a variety of genetically engineered (GE) crops in the 1990s and 2000s. We use corn yields and data from the US federal crop insurance program to evaluate these claims. An initial examination of yield responses to droughts in 1988 and 2012 suggests more robust yields in the latter period, in spite of very comparable weather stresses. We next consider side‐by‐side data collected under the Biotech Endorsement (BE) to the federal crop insurance program between 2008 and 2011. This endorsement provided substantial discounts for growers using certain GE hybrids, reflecting policymakers' beliefs that these hybrids had lower yield risk. We find that risk, as measured by the rate of indemnities paid per units insured, was significantly lower for crops insured under the BE. We also find that the difference in risk tends to be greater when growing conditions are less favorable.

Substantial Equivalence of a Transgenic Lemon Fruit Showing Postharvest Fungal Pathogens Resistance.

The development of genetically modified (GM) crops speeds up the obtainment of novel varieties with improved agronomic characteristics. However, the risk evaluation of the use of GMs is mandatory before their release in the market. In this paper, an untargeted and comprehensive nuclear magnetic resonance-based metabolomic study was carried out on the peel and flesh of a transgenic lemon clone (E23) expressing the chit42 gene and exhibiting an increased tolerance to some pathogenic fungi and on its wild type. Results highlighted a substantial equivalence of the metabolomics profile of the transgenic clone compared to the wild type. In addition, an enhanced response of the E23 clone toward fungal pathogens affecting the postharvest management in lemon was evidenced. These results confirm the potential of genetic engineering for the punctual modification of specific agronomic traits without altering the whole pattern of metabolites and open new perspectives for a more sustainable and effective management of specific postharvest diseases in citrus.

Change of soil physicochemical properties, bacterial community and aggregation during desertification of grasslands in the Tibetan Plateau

AbstractThe aim of this study was to evaluate the relationships among changes in the soil microstructure, soil physicochemical traits and microbial communities during desertification. Soil samples were collected from grasslands at different stages of desertification, from an area of the Tibetan Plateau. Soil aggregate fractionation and soil physicochemical properties were analysed using standard methods, and the abundance and diversity of bacteria associated with different aggregate fractions were estimated by quantitative PCR and Illumina Miseq amplicon sequencing. Sequential changes in response to desertification stages were detected in the analysed features. For instance, soil nutrients, microbial biomass C and N, water content and pH initially changed during the light desertification stage; then, the soil aggregation decreased during the intermediate stages; and finally, bacterial abundance and diversity decreased during heavy and severe desertification stages. During grassland desertification, vegetation coverage positively influenced soil aggregation by affecting soil properties (e.g., pH and SOC), whereas bacterial communities in FMi (free microaggregates) and FSC (free silt and clay) were negatively related to soil aggregation. This study reports novel information concerning the desertification process and the sequential modification of soil traits and interactions among soil physical properties (aggregate composition), soil nutrients and the soil microbial community in the grasslands of the Tibetan Plateau.Highlights Bacterial community was more sensitive in macroaggregates than in microaggregates. Composition of small macroaggregates and associated bacteria changed during desertification. Bacterial community in microaggregates, silt and clay negatively affected aggregation. Vegetation coverage affected aggregation by changing soil traits and bacterial community.

Review on Somatic Hybridization and its Role in Crop Improvement

Somatic hybridization is one of the most important uses of protoplast culture. This is particularly significant for hybridization between species or genera, which cannot be made to cross by conventional methods of sexual hybridization. The aim of somatic hybridization is to transfer traits which are desired and generate a beneficial crop plants without genetic engineering and as well as facilitate conventional breeding through providing novel crop lines. Somatic hybridization broadens the base of accessible germplasm and offers additional opportunities for introgression of desirable traits into cultivars. Plant protoplasts can be fused and the fusion products cultured to produce somatic hybrid plants. This technique has been used to produce germplasm previously unavailable to the plant breeder. Several researchers have emphasized production of hybrids between distantly related, sexually incompatible species, but many of these hybrids are sterile, precluding incorporation into a breeding program. Hence, to transfer traits such as disease and herbicide resistance, emphasis has shifted to production of hybrids between more closely related species. Novel variation has been observed in such somatic hybrids due to segregation of mixed organelles, cytoplasmic and nuclear gene recombination, and somaclonal variation. The unique gene combinations made possible by protoplast fusion ensure that new plant varieties will soon be derived from somatic hybridization. Even though measurable success of somatic hybridization in terms of cultivar release may still be limited, the potential for their use in plant breeding remains great. In general, somatic hybridization provides excellent opportunities for research on plant improvement, first by exploring genetic variations among the existing crops and then by attempting to transfer the available genetic information from one species to another through fusion of protoplasts isolated from somatic tissues of these crops. Somatic hybridization is contributing to plant breeding in overcoming common crossing barriers among plant species. Some of the problems could be overcome by somatic hybridization are: sexual incompatibility, nucellar embryogenesis, male or female sterility, transfer of resistance genes for biotic and abiotic stresses, to create novel hybrids with increased yields. Several steps are involved in the somatic hybridization process. Some of them are: identification of the source of protoplasts, isolation of protoplasts, planting of protoplasts, regeneration of plants, fusion of protoplasts, selection procedures, identification and characterization of somatic hybrid plants. Generally somatic hybridization is playing a key role in the production of novel interspecific and intergeneric hybrids and transfer of genes for diseases resistance, abiotic stress resistance, herbicide resistance and many other quality characters. Besides being of value for the transfer of unidentified genes, somatic hybridization is a tool for the modification and improvement of polygenic traits. Furthermore, the modification of organellar genetic material is possible via somatic hybridization since a mixture of the two fusion partners is obtained in the hybrid cell Production of hybrid plants through the fusion of protoplasts of two different plant species/varieties. Keywords: Somatic; Hybridization; Protoplast; Fusion. DOI: 10.7176/JBAH/10-11-04 Publication date: June 30 th 2020

Can dynamic network modelling be used to identify adaptive microbiomes?

Abstract In recent times, interest has grown in understanding how microbiomes – the collection of microorganisms in a specific environment – influence the survivability or fitness of their plant and animal hosts. The profound diversity of bacterial and fungal species found in certain environments, such as soil, provides a large pool of potential microbial partners that can interact in ways that reveal patterns of associations linking host–microbiome traits developed over time. However, most microbiome sequence data are reported as a community fingerprint, without analysis of interaction networks across microbial taxa through time. To address this knowledge gap, more robust tools are needed to account for microbiome dynamics that could signal a beneficial change to a plant or animal host. In this paper, we discuss applying mathematical tools, such as dynamic network modelling, which involves the use of longitudinal data to study system dynamics and microbiomes that identify potential alterations in microbial communities over time in response to an environmental change. In addition, we discuss the potential challenges and pitfalls of these methodologies, such as handling large amounts of sequencing data and accounting for random processes that influence community dynamics, as well as potential ways to address them. Ultimately, we argue that components of microbial community interactions can be characterized through mathematical models to reveal insights into complex dynamics associated with a plant or animal host trait. The inclusion of interaction networks in microbiome studies could provide insights into the behaviour of complex communities in tandem with host trait modification and evolution. A free Plain Language Summary can be found within the Supporting Information of this article.

Dissection of complex traits of tomato in the post-genome era.

We present the main advances of dissection of complex traits in tomato by omics, the genes identified to control complex traits and the application of CRISPR/Cas9 in tomato breeding. Complex traits are believed to be under the control of multiple genes, each with different effects and interaction with environmental factors. Advance development of sequencing and molecular technologies has enabled the recognition of the genomic structure of most organisms and the identification of a nearly limitless number of markers that have made it to accelerate the speed of QTL identification and gene cloning. Meanwhile, multiomics have been used to identify the genetic variations among different tomato species, determine the expression profiles of genes in different tissues and at distinct developmental stages, and detect metabolites in different pathways and processes. The combination of these data facilitates to reveal mechanism underlying complex traits. Moreover, mutants generated by mutagens and genome editing provide relatively rich genetic variation for deciphering the complex traits and exploiting them in tomato breeding. In this article, we present the main advances of complex trait dissection in tomato by omics since the release of the tomato genome sequence in 2012. We provide further insight into some tomato complex traits because of the causal genetic variations discovered so far and explore the utilization of CRISPR/Cas9 for the modification of tomato complex traits.

Genetic modification in Malaysia and India: current regulatory framework and the special case of non-transformative RNAi in agriculture.

Recent developments in modern biotechnology such as the use of RNA interference (RNAi) have broadened the scope of crop genetic modification. RNAi strategies have led to significant achievements in crop protection against biotic and abiotic stresses, modification of plant traits, and yield improvement. As RNAi-derived varieties of crops become more useful in the field, it is important to examine the capacity of current regulatory systems to deal with such varieties, and to determine if changes are needed to improve the existing frameworks. We review the biosafety frameworks from the perspective of developing countries that are increasingly involved in modern biotechnology research, including RNAi applications, and make some recommendations. Malaysia and India have approved laws regulating living modified organisms and products thereof, highlighting that the use of any genetically modified step requires regulatory scrutiny. In view of production methods for exogenously applied double-stranded RNAs and potential risks from the resulting double-stranded RNA-based products, we argue that a process-based system may be inappropriate for the non-transformative RNAi technology. We here propose that the current legislation needs rewording to take account of the non-transgenic RNAi technology, and discuss the best alternative for regulatory systems in India and Malaysia in comparison with the existing frameworks in other countries.

What is the available evidence for the range of applications of genome-editing as a new tool for plant trait modification and the potential occurrence of associated off-target effects: a systematic map

BackgroundWithin the last decades, genome-editing techniques such as CRISPR/Cas, TALENs, Zinc-Finger Nucleases, Meganucleases, Oligonucleotide-Directed Mutagenesis and base editing have been developed enabling a precise modification of DNA sequences. Such techniques provide options for simple, time-saving and cost-effective applications compared to other breeding techniques and hence genome editing has already been promoted for a wide range of plant species. Although the application of genome-editing induces less unintended modifications (off-targets) in the genome compared to classical mutagenesis techniques, off-target effects are a prominent point of criticism as they are supposed to cause unintended effects, e.g. genomic instability or cell death. To address these aspects, this map aims to answer the following question: What is the available evidence for the range of applications of genome-editing as a new tool for plant trait modification and the potential occurrence of associated off-target effects? This primary question will be considered by two secondary questions: One aims to overview the market-oriented traits being modified by genome-editing in plants and the other explores the occurrence of off-target effects.MethodsA literature search in nine bibliographic databases, Google Scholar, and 47 web pages of companies and governmental agencies was conducted using predefined and tested search strings in English language. Articles were screened on title/abstract and full text level for relevance based on pre-defined inclusion criteria. The relevant information of included studies were mapped using a pre-defined data extraction strategy. Besides a descriptive summary of the relevant literature, a spreadsheet containing all extracted data is provided.ResultsAltogether, 555 relevant articles from journals, company web pages and web pages of governmental agencies were identified containing 1328 studies/applications of genome-editing in model plants and agricultural crops in the period January 1996 to May 2018. Most of the studies were conducted in China followed by the USA. Genome-editing was already applied in 68 different plants. Although most of the studies were basic research, 99 different market-oriented applications were identified in 28 different crops leading to plants with improved food and feed quality, agronomic value like growth characteristics or increased yield, tolerance to biotic and abiotic stress, herbicide tolerance or industrial benefits. 252 studies explored off-target effects. Most of the studies were conducted using CRISPR/Cas. Several studies firstly investigated whether sites in the genome show similarity to the target sequence and secondly analyzed these potential off-target sites by sequencing. In around 3% of the analyzed potential off-target sites, unintended mutations were detected. Only a few studies conducted off-target analyses using unbiased detection methods (e.g. whole genome sequencing). No off-target effects that could be correlated to the genome-editing process were identified in these studies.ConclusionsThe rapid adoption in plant breeding was demonstrated by a considerable number of market oriented applications (crops and traits) described in publications worldwide. Studies investigating off-target effects are very heterogeneous in their structure and design. Therefore, an in-depth assessment regarding their weight of evidence is mandatory.

A Post-domestication Mutation, Dt2, Triggers Systemic Modification of Divergent and Convergent Pathways Modulating Multiple Agronomic Traits in Soybean

The semi-determinate stem growth habit in leguminous crops, similar to the “green revolution” semi-dwarf trait in cereals, is a key plant architecture trait that affects several other traits determining grain yield. In soybean semi-determinacy is modulated by a post-domestication gain-of-function mutation in the gene, Dt2, which encodes an MADS-box transcription factor. However, its role in systemic modification of stem growth and other traits is unknown. In this study, we show that Dt2 functions not only as a direct repressor of Dt1, which prevents terminal flowering, but also as a direct activator of putative floral integrator/identity genes including GmSOC1, GmAP1, and GmFUL, which likely promote flowering. We also demonstrate that Dt2 functions as a direct repressor of the putative drought-responsive transcription factor gene GmDREB1D, and as a direct activator of GmSPCH and GmGRP7, which are potentially associated with asymmetric division of young epidermal cells and stomatal opening, respectively, and may affect the plant's water-use efficiency (WUE). Intriguingly, Dt2 was found to be a direct activator or repressor of the precursors of eight microRNAs targeting genes potentially associated with meristem maintenance, flowering time, stomatal density, WUE, and/or stress responses. This study thus reveals the molecular basis of pleiotropy associated with plant productivity, adaptability, and environmental resilience.

Interactive role of epibrassinolide and hydrogen peroxide in regulating stomatal physiology, root morphology, photosynthetic and growth traits in Solanum lycopersicum L. under nickel stress

Nickel (Ni) is a fundamental component that assumes a vital role in managing plant growth and development. Its acquisition in soil is presently viewed as a consequential ecological issue imperilling crop productivity globally. Brassinosteroid and low concentration of H2O2 as signalling molecule could modify stomatal movement, root morphology, photosynthetic effectiveness and generation of antioxidants and finally growth traits to make the tomato plants more tolerant to Ni stress. Therefore, a study was conducted to study the effect of exogenously applied epibrassinolide (EBL; foliar spray) and H2O2 (root dipping) to nickel (Ni) stressed plants. EBL and H2O2 applied through different modes modified stomatal movement, root morphology, photosynthetic effectiveness and growth traits of Solanum lycopersicum L. plants grown under stress free and surplus Ni. The increased Ni- tolerance of tomato plants caused by EBL and H2O2 could be attributed to its capability to restrict Ni uptake, reduce Ni- inflicted oxidative burst as illustrated by lower levels of hydrogen peroxide, superoxide and electrolyte leakage in Ni- stressed plants. In addition, EBL and H2O2 increased the antioxidant capability in Ni stressed plants by sustaining increased activities of enzymes for ROS-detoxification, particularly catalase (CAT), guaiacol peroxidase (GPOX) and superoxide dismutase (SOD) and proline accumulation. These improved activities of antioxidant enzymes and accumulation of proline (osmolyte) elicited by the blend of EBL and H2O2, would have retained the ability to confer resilience to Solanum lycopersicum plants exposed to higher doses of Ni. This study further affirms that the combined application of EBL and H2O2 in various ways proved very effective to ameliorate the effects of Ni toxicity in tomato plants through modification of stomatal movement, root morphology, photosynthetic effectiveness and growth traits.

Mindfulness-based emotional eating awareness training: taking the emotional out of eating

PurposeEmotional eating is important to study and address because it predicts poor outcome in weight loss interventions. Interventions have only touched the surface in terms of addressing emotional eating. Mindfulness approaches can address emotional eating by modification of emotion regulation and appetitive traits. The current study involved development of an emotional eating-specific mindfulness intervention and assessment of its effect on appetitive traits associated with emotional eating.MethodsParticipants (n = 14; age M = 29 years; 90% female) completed baseline and end-of-intervention self-report measures of emotional eating, food-cue reactivity, mindfulness, intuitive eating, emotional impulse regulation, stress, and a behavioural measure of inhibitory control. During the 6-week intervention, mindfulness meditation skills were taught weekly embedded in a psycho-educational curriculum about emotional eating.ResultsPaired t tests, controlled for type 1 error, revealed significant improvements in food-cue reactivity, intuitive eating, emotional impulse regulation, inhibitory control and stress (ps < 0.05; d: 0.58–1.54). Changes in emotional eating approached significance (p = 0.075, d = 0.66).ConclusionThe intervention purposefully did not focus on weight loss and recruited participants who had self-declared difficulties with emotional eating. The positive outcomes suggest that intervening with mindfulness training before weight loss is attempted has the potential to change psychological factors that underpin overeating and undermine weight loss efforts. The study provides proof of principle as a basis to design a randomized control trial to assess rigorously the effectiveness of the intervention as a precursor to a weight loss intervention.Level of evidenceLevel IV, uncontrolled trial.