Advances In New Technology For Targeted Modification Of Plant Genomes

Over the past 50 years, biotechnology has been the major driving force for increasing crop productivity. Particularly, advances in plant genetic engineering technologies have opened up vast new opportunities for plant researchers and breeders to create new crop varieties with desirable traits. Recent development of precise genome modification methods, such as targeted gene knock-out/knock-in and precise gene replacement, moves genetic engineering to another level and offers even more potentials for improving crop production. The work provides an overview of the latest advances on precise genomic engineering technologies in plants. Topics include recombinase and engineered nucleases-mediated targeted modification, negative/positive selection-based homologous recombination and oligo nucleotide-mediated recombination. Finally, challenges and impacts of the new technologies on present regulations for genetic modification organisms (GMOs) will be discussed.

Over the last few decades, various techniques have been developed to alter the properties of plants and animals. While the targeted transfer of recombinant DNA into crop plants remains a valuable tool to achieve a desirable breeding outcome, integration of transgenes into the host genome has been random, which in part, leads to reduced acceptance of GMOs by the general population in some parts of the world. Likewise, methods of induced mutagenesis, such as TILLING, have the disadvantage that many mutations are induced per plant, which has to be removed again by expensive backcrossing. Advances in genome sequencing have provided more and more information on differences between susceptible and resistant varieties, which can now be directly targeted and modified using CRISPR/Cas9 technology. By selecting specific gRNAs occurrence of off-target modifications are comparatively low. ZFNs and TALENs- based approaches required re-engineering a new set of assembled polypeptides for every new target site for each experiment. The difficulty in cloning and protein engineering prevented these tools from being broadly adopted by the scientific community. Compared to these technologies, designing the CRISPR toolbox is much simpler and more flexible. CRISPR/Cas9 is versatile, less expensive and highly efficient. It has become the most widely used technology for genome editing in many organisms. Since its inception as a powerful genome-editing tool in late 2012, this breakthrough technology has completely changed how science is performed. The first few chapters in this book introduce the basic concept, design and implementation of CRISPR/Cas9 for different plant systems. They are followed by in-depth discussions on the legal and bio-safety issues accompanying commercialization and patenting of this emerging technology. Lastly, this book covers emerging areas of new tools and potential applications. We believe readers, novice and expert alike, will benefit from this all-in-one resource on genome editing for crop improvement. Chapter 17 is available open access under a Creative Commons Attribution 4.0 International License via link.springer.com.

Genetically engineered (GE) crops were first introduced commercially in the 1990s. After two decades of production, some groups and individuals remain critical of the technology based on their concerns about possible adverse effects on human health, the environment, and ethical considerations. At the same time, others are concerned that the technology is not reaching its potential to improve human health and the environment because of stringent regulations and reduced public funding to develop products offering more benefits to society. While the debate about these and other questions related to the genetic engineering techniques of the first 20 years goes on, emerging genetic-engineering technologies are adding new complexities to the conversation. Genetically Engineered Crops builds on previous related Academies reports published between 1987 and 2010 by undertaking a retrospective examination of the purported positive and adverse effects of GE crops and to anticipate what emerging genetic-engineering technologies hold for the future. This report indicates where there are uncertainties about the economic, agronomic, health, safety, or other impacts of GE crops and food, and makes recommendations to fill gaps in safety assessments, increase regulatory clarity, and improve innovations in and access to GE technology.

In this book, authors who are experts in their fields describe current advances on commercial crops and key enabling technologies that will underpin future advances in biotechnology. They discuss state of the art discoveries as well as future challenges. Tremendous progress has been made in introducing novel genes and traits into plant genomes since the first creation of transgenic plants thirty years ago, and the first commercialization of genetically modified maize in 1996. Consequently, cultivation of biotech crops with useful traits has increased more than 100-fold from 1.7 million hectares in 1996 to over 175 million hectares globally in 2013. This achievement has been made possible by continued advances in understanding the basic molecular biology of regulatory sequences to modulate gene expression, enhancement of protein synthesis and new technologies for transformation of crop plants. This book has three sections that encompass knowledge on genetically modified (GM) food crops that are currently used by consumers, those that are anticipated to reach the market place in the near future and enabling technologies that will facilitate the development of next generation GM crops. Section I focuses only on genetically modified maize and soybean (3 chapters each), while Section II discusses the GM food crops rice, wheat, sorghum, vegetables and sugar cane. Section III covers exciting recent developments in several novel enabling technologies, including gene targeting, minichromosomes, and in planta transient expression systems.

This book serves the teachers, researchers and the students as a handy and concise reference as well as guidebook while designing and planning for use of the advanced technologies for crop improvement. The content of the book is designed to cover the latest genome engineering techniques for crop improvement. The conventional breeding has got its limitations such as non-availability of desired genes within the genepool. In many cases, breeding has been highly used and it has nearly reached its highest limit so far as the productivity and production of crops are concerned. However, with increasing need of food and decreasing resources, including water, land, labour, etc., to feed the growing population, the alternative available ways of increasing crop productivity need to be explored and exploited. Genome engineering has a wide scope that includes technologies such as genetic engineering and transgenesis, RNA technologies, CRISPR, cisgenics and subgenics for better productivity and more efficient biotic and abiotic stress management. Therefore, the book is planned to enlighten the readers with the advanced technologies with examples and case studies, whenever possible. Efforts will be made to emphasize on general efforts on various major food crops; however, it would also be made clear that such efforts could be taken as proofs of concepts and that this could be extrapolated keeping the demand in mind.

Assists policymakers in evaluating the appropriate scientific methods for detecting unintended changes in food and assessing the potential for adverse health effects from genetically modified products. In this book, the committee recommended that greater scrutiny should be given to foods containing new compounds or unusual amounts of naturally occurring substances, regardless of the method used to create them. The book offers a framework to guide federal agencies in selecting the route of safety assessment. It identifies and recommends several pre- and post-market approaches to guide the assessment of unintended compositional changes that could result from genetically modified foods and research avenues to fill the knowledge gaps.

Part 1 of this volume reviews advances in gene editing techniques such as insertion-based genome edits, base editing, guide RNAs and CRISPR/Cas off targeting. Part 2 surveys applications of gene editing in key cereal and vegetable crops.