Sunday Evening News 390 - Week 35 - 2024
Weekly report on genetic engineering, genome editing, biotechnology and legal regulations.
August 2024-26-08 - 2024-01-09
Ein weiser Spruch von Ex-Kanzlerin A. Merkel: „Es gibt einen großen Unterschied zwischen Erwarten und Erleben“
Kollege Nellen hat ein Glossar zur Thematik „CRISPR/Cas“ zusammengestellt: https://www.biowisskomm.de/wp-content/uploads/2024/08/BioWissKomm_Glossar.pdf
Es ist umfassend und nützlich. Ich möchte es Ihnen nicht vorbehalten.
Am 03.09.2024 berät der Berufungsausschuss über den Kommissionsvorschlag zur Zulassung von Mais MON 89034 × 1507 × MON 88017 x 59122 und acht Unterkombinationen*, Mais MON 89034 × 1507 × NK603*, Mais DP202216 sowie Baumwolle COT102. Wie traditionell üblich, werden die Mitgliedsstaaten sich zu keiner Entscheidung durchringen. Sie überlassen die Entscheidung der Kommission. Eine Zulassung dieser gv-Pflanzen ist noch dieses Jahr zu erwarten.
Die ► Debatten auf dem Weg zum Trilogverfahren wurden aktualisiert und um die beratenden Ausschüsse erweitert.
A wise saying from former Chancellor A. Merkel: “There is a big difference between expecting and experiencing”
On 03.09.2024, the Appeal Committee will discuss the Commission proposal for the approval of maize MON 89034 × 1507 × MON 88017 x 59122 and eight sub-combinations*, maize MON 89034 × 1507 × NK603*, maize DP202216 and cotton COT102. As is traditionally the case, the member states will not come to a decision. They leave the decision to the Commission. These GM plants are expected to be approved this year.
The ► Debates on the way to the trilogue procedure have been updated and expanded to include the advisory committees
Meetings - Tagungen
VLOG: Internationale Konferenz zur Zukunft der Ohne-Gentechnik-Wirtschaft
7-8 October 2024, Frankfurt/Main, Germany
Navigating The Future of Non-GMO Production: Challenges, Regulatory Outlook, and Market Potential
….und eine Pressemeldung dazu: Manzanaro S.S.: Fragwürdige Neutralität: Ungarischer Minister eröffnet Ohne-Gentechnik-
Konferenz
….and a corresponding press release: Hungarian Presidency minister to open annual non-GMO summit
VBIO-Vortragsreihe: „Epigenetik: Was wir von Pflanzen darüber gelernt haben“
Press Releases -Media / Presse- und Medienberichte
National Geographic: Streit um Genfood: Wie viel Gentechnik darf ins Essen?
AGDAILY: USDA clears path for GM wheat, yet global market uncertain
https://www.agdaily.com/crops/usda-clears-path-for-gm-wheat/
Briere K.: GM wheat moves closer in U.S.
https://www.producer.com/news/gm-wheat-moves-closer-in-u-s/
Hill C.: Gene-edited wheat harvested in Norfolk ahead of farm trials
https://www.edp24.co.uk/news/24545783.gene-edited-wheat-harvested-norfolk-ahead-farm-trials/
Only some selected press releases or media reports are listed here. The daily up-date of the press releases and
media reports are ►here: August week 35
Publications – Publikationen
Zhang H., Zhu J.K. (2024): Epigenetic gene regulation in plants and its potential applications in crop improvement.
Nat Rev Mol Cell Biol | https://doi.org/10.1038/s41580-024-00769-1
DNA methylation, also known as 5-methylcytosine, is an epigenetic modification that has crucial functions in plant growth, development and adaptation. The cellular DNA methylation level is tightly regulated by the combined action of DNA methyltransferases and demethylases. Protein complexes involved in the targeting and interpretation of DNA methylation have been identified, revealing intriguing roles of methyl-DNA binding proteins and molecular chaperones. Structural studies and in vitro reconstituted enzymatic systems have provided mechanistic insights into RNA-directed DNA methylation, the main pathway catalysing de novo methylation in plants. A better understanding of the regulatory mechanisms will enable locus-specific manipulation of the DNA methylation status. CRISPR–dCas9-based epigenome editing tools are being developed for this goal. Given that DNA methylation patterns can be stably transmitted through meiosis, and that large phenotypic variations can be contributed by epimutations, epigenome editing holds great promise in crop breeding by creating additional phenotypic variability on the same genetic material.
https://www.nature.com/articles/s41580-024-00769-1
Noack F., Engist D., Gantois J., Gaur V., Hyjazie B.F., Larsen A. et al. (2024): Environmental impacts of genetically modified
crops. Science 385, Issue 6712 | DOI: 10.1126/science.ado9340
INTRODUCTION: In recent decades, genetically modified (GM) crops have been widely adopted by some of the world’s leading agricultural nations, but the full extent of their environmental impacts remains largely unknown. Initial studies conducted in controlled environments provided valuable insights into the mechanisms that relate GM crops to the environment but offered an incomplete picture of their indirect environmental consequences. Adopting GM crops often leads to changes in other agricultural practices, such as pesticide use, cropping, and tillage patterns, with profound environmental implications (see figure). Furthermore, with widespread adoption, these changes become large in scale and can lead to substantial economic and ecological spillovers through markets and ecological interactions, influencing the environmental outcomes of nonadopting regions. These spillovers can also lead to opposing outcomes in adopting and nonadopting regions. For example, increased profits from GM crop adoption can incentivize agricultural expansion and intensification in adopting countries with potentially negative environmental impacts. However, the increased global supply from these changes in adopting countries can reduce expansion and intensification in nonadopting countries through market effects with potentially positive environmental implications. The goal of our review is to synthesize the recent understanding of the environmental implications of GM crop adoption, with a particular focus on indirect effects and spatial spillovers.
Much of the existing literature focuses on the direct effects of GM crop adoption on agricultural outcomes and, to a lesser extent, its implications for the environment and human health. Recent studies employing causal inference methods have contributed to our understanding of the combined direct and indirect impacts of GM crop adoption through environmental management changes, including effects on yields, deforestation, biodiversity, and human health. Their findings paint a nuanced picture of GM crop adoption, with mostly positive impacts on yields and mixed effects on pesticide use, biodiversity, deforestation, and human health. These studies also find negative health effects from increased glyphosate use, possibly counteracted by reduced toxicity of insecticide applications due to the adoption of insect-resistant GM crops. However, the few studies that evaluate long-term consequences suggest that short-term benefits may decrease if pest resistance is not well managed. In addition, new results show that GM crop adoption increases deforestation locally, in contrast to previous studies that found a land-sparing global effect of GM crop adoption. Lastly, the evidence for the impacts of GM crop adoption on biodiversity is mixed. For example, a recent study found that although the overall impact of GM crops on bird diversity is small, the overall effect is composed of positive effects on insectivorous species and negative effects on plant and seed-eating species. While these studies greatly advance our understanding of the direct and indirect environmental effects of GM crops, they still do not fully assess the spillover effects on areas and regions that have not adopted GM crops.
OUTLOOK: To date, large-scale GM crop adoption has been limited to just two traits with different environmental and human health effects: herbicide tolerance and insect resistance. New GM crops and gene-edited versions with different traits, such as drought resistance, would likely have different environmental and human health impacts. Therefore, improving regulations and resistance management, providing incentives for the development and commercialization of new traits that align with social goals and human welfare, and gathering more comprehensive and detailed environmental data, especially on biodiversity, are critical for guiding agricultural innovations toward greater sustainability and allowing an accurate assessment of their impacts.
https://www.science.org/doi/10.1126/science.ado9340
Guo, J., Gong, L., Yu, H. et al. (2024): Engineered minimal type I CRISPR-Cas system for transcriptional activation and
base editing in human cells. Nat Commun 15, 7277 | https://doi.org/10.1038/s41467-024-51695-x
Type I CRISPR-Cas systems are widespread and have exhibited high versatility and efficiency in genome editing and gene regulation in prokaryotes. However, due to the multi-subunit composition and large size, their application in eukaryotes has not been thoroughly investigated. Here, we demonstrate that the type I-F2 Cascade, the most compact among type I systems, with a total gene size smaller than that of SpCas9, can be developed for transcriptional activation in human cells. The efficiency of the engineered I-F2 tool can match or surpass that of dCas9. Additionally, we create a base editor using the I-F2 Cascade, which induces a considerably wide editing window (~30 nt) with a bimodal distribution. It can expand targetable sites, which is useful for disrupting functional sequences and genetic screening. This research underscores the application of compact type I systems in eukaryotes, particularly in the development of a base editor with a wide editing window.
https://www.nature.com/articles/s41467-024-51695-x
Nishio H., Cano-Ramirez D.L., Muranaka T., +4, Dodd A.N. (2024): Circadian and environmental signal integration in a natural
population of Arabidopsis. PNAS 121 (35) e2402697121 | https://doi.org/10.1073/pnas.2402697121
Plants sense and respond to environmental cues during 24 h fluctuations in their environment. This requires the integration of internal cues such as circadian timing with environmental cues such as light and temperature to elicit cellular responses through signal transduction. However, the integration and transduction of circadian and environmental signals by plants growing in natural environments remains poorly understood. To gain insights into 24 h dynamics of environmental signaling in nature, we performed a field study of signal transduction from the nucleus to chloroplasts in a natural population of Arabidopsis halleri. Using several modeling approaches to interpret the data, we identified that the circadian clock and temperature are key regulators of this pathway under natural conditions. We identified potential time-delay steps between pathway components, and diel fluctuations in the response of the pathway to temperature cues that are reminiscent of the process of circadian gating. We found that our modeling framework can be extended to other signaling pathways that undergo diel oscillations and respond to environmental cues. This approach of combining studies of gene expression in the field with modeling allowed us to identify the dynamic integration and transduction of environmental cues, in plant cells, under naturally fluctuating diel cycles.
https://www.pnas.org/doi/10.1073/pnas.2402697121
Tu M., Wang R., Guo W., Xu S. et al. (2024): A CRISPR/Cas9-induced male-sterile line facilitating easy hybrid production in
polyploid rapeseed (Brassica napus). Horticulture Research 11 (7)| uhae139, https://doi.org/10.1093/hr/uhae139
Rapeseed is a globally significant oilseed crop cultivated to meet the increasing demand for vegetable oil. In order to enhance yield and sustainability, breeders have adopted the development of rapeseed hybrids as a common strategy. However, current hybrid production systems in rapeseed have various limitations, necessitating the development of a simpler and more efficient approach. In this study, we propose a novel method involving the targeted disruption of Defective in Anther Dehiscence1 of Brassica napus (BnDAD1), an essential gene in the jasmonic acid biosynthesis pathway, using CRISPR/Cas9 technology, to create male-sterile lines. BnDAD1 was found to be dominantly expressed in the stamen of rapeseed flower buds. Disrupting BnDAD1 led to decreased levels of α-linolenic acid and jasmonate in the double mutants, resulting in defects in anther dehiscence and pollen maturation. By crossing the double mutant male-sterile lines with male-fertile lines, a two-line system was demonstrated, enabling the production of F1 seeds. The male-sterile trait of the bndad1 double mutant lines was maintainable by applying exogenous methyl jasmonate and subsequently self-pollinating the flowers. This breakthrough holds promising potential for harnessing heterosis in rapeseed and offers a simpler and more efficient method for producing hybrid seeds.
https://academic.oup.com/hr/article/11/7/uhae139/7684221?login=true
Lou H., Wang F., Zhang J., Wei G. et al. (2024): JrGA20ox1-transformed rootstocks deliver drought response signals to
wild-type scions in grafted walnut. Horticulture Research 11 (7), uhae143, https://doi.org/10.1093/hr/uhae143
Targeted regulation using transgrafting technology has become a trend. However, the mechanisms of transgene-derived signal communication between rootstocks and scions remain unclear in woody plants. Here, we grafted wild-type (WT) walnut (Juglans regia L.) on WT (WT/WT), JrGA20ox1 (encodes a gibberellin 20-oxidase)-overexpressing (WT/OE), and JrGA20ox1-RNAi transformation (WT/RNAi) walnut in vitro. We aimed to elucidate the mechanisms of JrGA20ox1-derived signal communication under PEG-simulated drought stress between rootstocks and scions in walnut. We demonstrated that JrGA20ox1-OE and JrGA20ox1-RNAi rootstocks could transport active gibberellins (GAs) and JrGA20ox1-RNAi vector-produced sRNAs to WT scions under PEG-simulated drought stress, respectively. The movement of sRNAs further led to a successive decline in JrGA20ox1 expression and active GA content. Meanwhile, unknown mobile signals may move between rootstocks and scions. These mobile signals reduced the expression of a series of GA-responsive and GA-non-responsive genes, and induced ROS production in guard cells and an increase in ABA content, which may contribute to the drought tolerance of WT/RNAi, while the opposite occurred in WT/OE. The findings suggest that JrGA20ox1-derived rootstock-to-scion movement of signals is involved in drought tolerance of scions. Our research will provide a feasible approach for studying signal communication in woody plants.
https://academic.oup.com/hr/article/11/7/uhae143/7680575
Kutyrieva-Nowak N., Leszczuk A., Denic D., Bellaidi S. et al. (2024): In vivo and ex vivo study on cell wall components as part
of the network in tomato fruit during the ripening process. Horticulture Research 11 (7), uhae145 | https://doi.org/10.1093/hr/uhae145
Ripening is a process involving various morphological, physiological, and biochemical changes in fruits. This process is affected by modifications in the cell wall structure, particularly in the composition of polysaccharides and proteins. The cell wall assembly is a network of polysaccharides and proteoglycans named the arabinoxylan pectin arabinogalactan protein1 (APAP1). The complex consists of the arabinogalactan protein (AGP) core with the pectin domain including arabinogalactan (AG) type II, homogalacturonan (HG), and rhamnogalacturonan I (RG-I). The present paper aims to determine the impact of a disturbance in the synthesis of one constituent on the integrity of the cell wall. Therefore, in the current work, we have tested the impact of modified expression of the SlP4H3 gene connected with proline hydroxylase (P4H) activity on AGP presence in the fruit matrix. Using an immunolabelling technique (CLSM), an immunogold method (TEM), molecular tools, and calcium mapping (SEM-EDS), we have demonstrated that disturbances in AGP synthesis affect the entire cell wall structure. Changes in the spatio-temporal AGP distribution may be related to the formation of a network between AGPs with other cell wall components. Moreover, the modified structure of the cell wall assembly induces morphological changes visible at the cellular level during the progression of the ripening process. These results support the hypothesis that AGPs and pectins are required for the proper progression of the physiological processes occurring in fruits.
https://academic.oup.com/hr/article/11/7/uhae145/7680592?login=false
Xiao-Yuan Yang et al. (2024): DdmDE eliminates plasmid invasion by DNA-guided DNA targeting, Cell |
DOI: 10.1016/j.cell.2024.07.028
Horizontal gene transfer is a key driver of bacterial evolution, but it also presents severe risks to bacteria by introducing invasive mobile genetic elements. To counter these threats, bacteria have developed various defense systems, including prokaryotic Argonautes (pAgos) and the DNA defense module DdmDE system. Through biochemical analysis, structural determination, and in vivo plasmid clearance assays, we elucidate the assembly and activation mechanisms of DdmDE, which eliminates small, multicopy plasmids. We demonstrate that DdmE, a pAgo-like protein, acts as a catalytically inactive, DNA-guided, DNA-targeting defense module. In the presence of guide DNA, DdmE targets plasmids and recruits a dimeric DdmD, which contains nuclease and helicase domains. Upon binding to DNA substrates, DdmD transitions from an autoinhibited dimer to an active monomer, which then translocates along and cleaves the plasmids. Together, our findings reveal the intricate mechanisms underlying DdmDE-mediated plasmid clearance, offering fundamental insights into bacterial defense systems against plasmid invasions.