Impacts of the regulatory environment for gene editing on delivering beneficial products

Genome editing in food and agriculture: from regulations to consumer perspectives

Genome editing (GE) has emerged as a technology that could revolutionize food and agricultural production. While its advent has evoked enthusiasm for a more sustainable food system, there exists heterogeneity in regulations and public opinions regarding the technology. This review discusses evidence on the implications of government regulations on GE, and perceptions of genome-edited (GEd) food and related regulations. The review highlights consumers' positive attitude and preference for GEd foods when compared with genetically modified foods, despite the limited awareness and knowledge of GE technology. While policy changes might trigger debates, providing tailored benefits, information to consumers could further improve their attitude toward GE.

Drought Stress Amelioration Attributes of Plant-Associated Microbiome on Agricultural Plants

The future global food security depends on the availability of water for agriculture. Yet, the ongoing rise in nonagricultural uses for water, such as urban and industrial uses, and growing environmental quality concerns have increased pressure of irrigation water demand and posed danger to food security. Nevertheless, its severity and duration are predicted to rise shortly. Drought pressure causes stunted growth, severe damage to photosynthesis activity, loss in crop yield, reduced seed germination, and reduced nutrient intake by plants. To overcome the effects of a devastating drought on plants, it is essential to think about the causes, mechanisms of action, and long-term agronomy management and genetics. As a result, there is an urgent need for long-term medication to deal with the harmful effects of drought pressure. The review focuses on the adverse impact of drought on the plant, physiological, and biochemical aspects, and management measures to control the severity of drought conditions. This article reviews the role of genome editing (GE) technologies such as CRISPR 9 (CRISPR-Cas9) related spaces and short palindromic relapse between proteins in reducing the effects of phytohormones, osmolytes, external compounds, proteins, microbes (plant growth-promoting microorganism [PGPM]), approach omics, and drought on plants that support plant growth. This research is to examine the potential of using the microbiome associated with plants for drought resistance and sustainable agriculture. Researchers also advocate using a mix of biotechnology, agronomic, and advanced GE technologies to create drought-tolerant plant varieties.

CRISPR technology towards genome editing of the perennial and semi-perennial crops citrus, coffee and sugarcane

Gene editing technologies have opened up the possibility of manipulating the genome of any organism in a predicted way. CRISPR technology is the most used genome editing tool and, in agriculture, it has allowed the expansion of possibilities in plant biotechnology, such as gene knockout or knock-in, transcriptional regulation, epigenetic modification, base editing, RNA editing, prime editing, and nucleic acid probing or detection. This technology mostly depends on in vitro tissue culture and genetic transformation/transfection protocols, which sometimes become the major challenges for its application in different crops. Agrobacterium-mediated transformation, biolistics, plasmid or RNP (ribonucleoprotein) transfection of protoplasts are some of the commonly used CRISPR delivery methods, but they depend on the genotype and target gene for efficient editing. The choice of the CRISPR system (Cas9, Cas12), CRISPR mechanism (plasmid or RNP) and transfection technique (Agrobacterium spp., PEG solution, lipofection) directly impacts the transformation efficiency and/or editing rate. Besides, CRISPR/Cas technology has made countries rethink regulatory frameworks concerning genetically modified organisms and flexibilize regulatory obstacles for edited plants. Here we present an overview of the state-of-the-art of CRISPR technology applied to three important crops worldwide (citrus, coffee and sugarcane), considering the biological, methodological, and regulatory aspects of its application. In addition, we provide perspectives on recently developed CRISPR tools and promising applications for each of these crops, thus highlighting the usefulness of gene editing to develop novel cultivars.

Processes for regulating genetically modified and gene edited plants

Innovation in agriculture has been essential in improving productivity of crops and forages to support a growing population, improving living standards while contributing toward maintaining environment integrity, human health, and wellbeing through provision of more nutritious, varied, and abundant food sources. A crucial part of that innovation has involved a range of techniques for both expanding and exploiting the genetic potential of plants. However, some techniques used for generating new variation for plant breeders to exploit are deemed higher risk than others despite end products of both processes at times being for all intents and purposes identical for the benefits they provide. As a result, public concerns often triggered by poor communication from innovators, resulting in mistrust and suspicion has, in turn, caused the development of a range of regulatory systems. The logic and motivations for modes of regulation used are reviewed and how the benefits from use of these technologies can be delivered more efficiently and effectively is discussed.

Genome editing for healthy crops: traits, tools and impacts

Crop cultivars in commercial use have often been selected because they show high levels of resistance to pathogens. However, widespread cultivation of these crops for many years in the environments favorable to a pathogen requires durable forms of resistance to maintain "healthy crops". Breeding of new varieties tolerant/resistant to biotic stresses by incorporating genetic components related to durable resistance, developing new breeding methods and new active molecules, and improving the Integrated Pest Management strategies have been of great value, but their effectiveness is being challenged by the newly emerging diseases and the rapid change of pathogens due to climatic changes. Genome editing has provided new tools and methods to characterize defense-related genes in crops and improve crop resilience to disease pathogens providing improved food security and future sustainable agricultural systems. In this review, we discuss the principal traits, tools and impacts of utilizing genome editing techniques for achieving of durable resilience and a "healthy plants" concept.

Guidelines for Performing CRISPR/Cas9 Genome Editing for Gene Validation and Trait Improvement in Crops

With the rapid advances in plant genome editing techniques over the past 10 years, more efficient and powerful crop genome editing applications are now possible. Candidate genes for key traits can be validated using CRISPR/Cas9-based knockouts and through the up- and down-regulation of gene expression. Likewise, new trait improvement approaches can take advantage of targeted editing to improve stress tolerance, disease resistance, and nutritional traits. However, several key steps in the process can prove tricky for researchers who might be new to plant genome editing. Here, we present step-by-step guidelines and best practices for a crop genome editing pipeline that should help to improve the rate of success. Important factors in the process include proper target sequence analysis and single guide RNA (sgRNA) design, sequencing of the target site in the genotypes of interest, performing an in vitro CRISPR/Cas9 ribonucleoprotein (RNP) assay to validate the designed sgRNAs, preparing the transformation constructs, considering a protoplast editing step as further validation, and, finally, stable plant transformation and mutation detection by Sanger and/or next-generation sequencing. With these detailed guidelines, a new user should be able to quickly set up a genome editing pipeline in their crop of interest and start making progress with the different CRISPR/Cas-based editing variants for gene validation and trait improvement purposes.

From Transgenesis to Genome Editing in Crop Improvement: Applications, Marketing, and Legal Issues

The biotechnological approaches of transgenesis and the more recent eco-friendly new breeding techniques (NBTs), in particular, genome editing, offer useful strategies for genetic improvement of crops, and therefore, recently, they have been receiving increasingly more attention. The number of traits improved through transgenesis and genome editing technologies is growing, ranging from resistance to herbicides and insects to traits capable of coping with human population growth and climate change, such as nutritional quality or resistance to climatic stress and diseases. Research on both technologies has reached an advanced stage of development and, for many biotech crops, phenotypic evaluations in the open field are already underway. In addition, many approvals regarding main crops have been granted. Over time, there has been an increase in the areas cultivated with crops that have been improved through both approaches, but their use in various countries has been limited by legislative restrictions according to the different regulations applied which affect their cultivation, marketing, and use in human and animal nutrition. In the absence of specific legislation, there is an on-going public debate with favorable and unfavorable positions. This review offers an updated and in-depth discussion on these issues.

Are null segregants new combinations of heritable material and should they be regulated?

Through genome editing and other techniques of gene technology, it is possible to create a class of organism called null segregants. These genetically modified organisms (GMOs) are products of gene technology but are argued to have no lingering vestige of the technology after the segregation of chromosomes or deletion of insertions. From that viewpoint regulations are redundant because any unique potential for the use of gene technology to cause harm has also been removed. We tackle this question of international interest by reviewing the early history of the purpose of gene technology regulation. The active ingredients of techniques used for guided mutagenesis, e.g., site-directed nucleases, such as CRISPR/Cas, are promoted for having a lower potential per reaction to create a hazard. However, others see this as a desirable industrial property of the reagents that will lead to genome editing being used more and nullifying the promised hazard mitigation. The contest between views revolves around whether regulations could alter the risks in the responsible use of gene technology. We conclude that gene technology, even when used to make null segregants, has characteristics that make regulation a reasonable option for mitigating potential harm. Those characteristics are that it allows people to create more harm faster, even if it creates benefits as well; the potential for harm increases with increased use of the technique, but safety does not; and regulations can control harm scaling.

Genome editing in maize: Toward improving complex traits in a global crop

Recent advances in genome editing have enormously enhanced the effort to develop biotechnology crops for more sustainable food production. CRISPR/Cas, the most versatile genome-editing tool, has shown the potential to create genome modifications that range from gene knockout and gene expression pattern modulations to allele-specific changes in order to design superior genotypes harboring multiple improved agronomic traits. However, a frequent bottleneck is the delivery of CRISPR/Cas to crops that are less amenable to transformation and regeneration. Several technologies have recently been proposed to overcome transformation recalcitrance, including HI-Edit/IMGE and ectopic/transient expression of genes encoding morphogenic regulators. These technologies allow the eroding of the barriers that make crops inaccessible for genome editing. In this review, we discuss the advances in genome editing in crops with a particular focus on the use of technologies to improve complex traits such as water use efficiency, drought stress, and yield in maize.

Lignin engineering in forest trees: From gene discovery to field trials

Wood is an abundant and renewable feedstock for the production of pulp, fuels, and biobased materials. However, wood is recalcitrant toward deconstruction into cellulose and simple sugars, mainly because of the presence of lignin, an aromatic polymer that shields cell-wall polysaccharides. Hence, numerous research efforts have focused on engineering lignin amount and composition to improve wood processability. Here, we focus on results that have been obtained by engineering the lignin biosynthesis and branching pathways in forest trees to reduce cell-wall recalcitrance, including the introduction of exotic lignin monomers. In addition, we draw general conclusions from over 20 years of field trial research with trees engineered to produce less or altered lignin. We discuss possible causes and solutions for the yield penalty that is often associated with lignin engineering in trees. Finally, we discuss how conventional and new breeding strategies can be combined to develop elite clones with desired lignin properties. We conclude this review with priorities for the development of commercially relevant lignin-engineered trees.

The economics and policy of genome editing in crop improvement

In this review article we analyze the economics of genome editing and its potential long-term effect on crop improvement and agriculture. We describe the emergence of genome editing as a novel platform for crop improvement, distinct from the existing platforms of plant breeding and genetic engineering. We review key technical characteristics of genome editing and describe how it enables faster trait development, lower research and development costs, and the development of novel traits not possible through previous crop improvement methods. Given these fundamental technical and economic advantages, we describe how genome editing can greatly increase the productivity and broaden the scope of crop improvement with potential outsized economic effects. We further discuss how the global regulatory policy environment, which is still emerging, can shape the ultimate path of genome editing innovation, its effect on crop improvement, and its overall socioeconomic benefits to society.

Novel Approaches for Sustainable Horticultural Crop Production: Advances and Prospects

Reduction of plant growth, yield and quality due to diverse environmental constrains along with climate change significantly limit the sustainable production of horticultural crops. In this review, we highlight the prospective impacts that are positive challenges for the application of beneficial microbial endophytes, nanomaterials (NMs), exogenous phytohormones strigolactones (SLs) and new breeding techniques (CRISPR), as well as controlled environment horticulture (CEH) using artificial light in sustainable production of horticultural crops. The benefits of such applications are often evaluated by measuring their impact on the metabolic, morphological and biochemical parameters of a variety of cultures, which typically results in higher yields with efficient use of resources when applied in greenhouse or field conditions. Endophytic microbes that promote plant growth play a key role in the adapting of plants to habitat, thereby improving their yield and prolonging their protection from biotic and abiotic stresses. Focusing on quality control, we considered the effects of the applications of microbial endophytes, a novel class of phytohormones SLs, as well as NMs and CEH using artificial light on horticultural commodities. In addition, the genomic editing of plants using CRISPR, including its role in modulating gene expression/transcription factors in improving crop production and tolerance, was also reviewed.

CRISPR/Cas- and Topical RNAi-Based Technologies for Crop Management and Improvement: Reviewing the Risk Assessment and Challenges Towards a More Sustainable Agriculture

Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated gene (Cas) system and RNA interference (RNAi)-based non-transgenic approaches are powerful technologies capable of revolutionizing plant research and breeding. In recent years, the use of these modern technologies has been explored in various sectors of agriculture, introducing or improving important agronomic traits in plant crops, such as increased yield, nutritional quality, abiotic- and, mostly, biotic-stress resistance. However, the limitations of each technique, public perception, and regulatory aspects are hindering its wide adoption for the development of new crop varieties or products. In an attempt to reverse these mishaps, scientists have been researching alternatives to increase the specificity, uptake, and stability of the CRISPR and RNAi system components in the target organism, as well as to reduce the chance of toxicity in nontarget organisms to minimize environmental risk, health problems, and regulatory issues. In this review, we discuss several aspects related to risk assessment, toxicity, and advances in the use of CRISPR/Cas and topical RNAi-based technologies in crop management and breeding. The present study also highlights the advantages and possible drawbacks of each technology, provides a brief overview of how to circumvent the off-target occurrence, the strategies to increase on-target specificity, the harm/benefits of association with nanotechnology, the public perception of the available techniques, worldwide regulatory frameworks regarding topical RNAi and CRISPR technologies, and, lastly, presents successful case studies of biotechnological solutions derived from both technologies, raising potential challenges to reach the market and being social and environmentally safe.

Enabling Genome Editing for Enhanced Agricultural Sustainability

Agricultural sustainability encompasses environmental, social, and economic aspects, all of which are continually shifting due changing environmental pressures and societal expectations. A range of strategies are required to address these challenges, and these include the use of innovation and adoption of the best available practices and technologies. Advances in biotechnologies, including genome editing, and their application in plant breeding and research are expected to provide a range of benefits that contribute to all aspects of agricultural sustainability. However, adoption of these technologies needs to be supported by proportionate, coherent, forward-looking, and adaptable policies and regulatory approaches. In this Perspective, we reflect on the regulatory challenges associated with commercialising a transgenic crop, and developments thus far in providing regulatory clarity for genome edited crops. We aim to demonstrate that much remains to be done to shift towards a more proportionate and enabling approach before the potential benefits of genome edited crops can be realised. The implications of precautionary and disproportionate regulation are also discussed.