Assistant Professor at UC Berkeley
Talk title: “Nanomaterials Enable Delivery of Genetic Material Without Transgene Integration in Mature Plants”
Abstract: Genetic engineering of plants is at the core of sustainability efforts, natural product synthesis, and agricultural crop engineering. The plant cell wall is a barrier that limits the ease and throughput with which exogenous biomolecules can be delivered to plants. Current delivery methods either suffer from host range limitations, low transformation efficiencies, tissue regenerability, tissue damage, or unavoidable DNA integration into the host genome. Here, we demonstrate efficient diffusion-based biomolecule delivery into tissues and organs of intact plants of several species with a suite of pristine and chemically-functionalized high aspect ratio nanomaterials. Efficient DNA delivery and strong protein expression without transgene integration is accomplished in mature Nicotiana benthamiana, Eruca sativa (arugula), Triticum aestivum (wheat), and Gossypium hirsutum (cotton) leaves and arugula protoplasts. Notably, we demonstrate that transgene expression is transient and devoid of transgene integration into the plant host genome, of potential utility for easing regulatory oversight of transformed crops as genetically modified organisms (GMOs). We demonstrate that our platform can be applied for CRISPR-based genome editing for transient expression of Cas9 and gRNAs. We also demonstrate a second nanoparticle-based strategy in which small interfering RNA (siRNA) is delivered to mature Nicotiana benthamiana leaves and effectively silences a gene with 95% efficiency. We find that nanomaterials both facilitate biomolecule transport into plant cells, while also protecting polynucleotides such as RNA from nuclease degradation. DNA origami and nanostructures further enable siRNA delivery to plants at programmable nanostructure loci, which we use to elucidate force-independent transport phenomena of nanoparticles across the plant cell wall. Our work provides a tool for species-independent, targeted, and passive delivery of genetic material, without transgene integration, into plant cells for diverse plant biotechnology applications.
Assistant Professor at Virginia Tech
Talk title: “Gene Editing Through Transient Transformation and Regeneration of Protoplasts”
Abstract: Novel plant breeding technologies, particularly CRISPR/Cas9 and related tools, have great promise for accelerating and expanding the potential of crop breeding programs. The ability to apply gene-editing technology without the need for intermediate transgenic stages can facilitate bringing new germplasm to the agricultural market by circumventing the need to cross out the foreign constructs used to modify the plant’s own genome. Here, I will talk about transient transformation of protoplasts and subsequent regeneration of edited cells as a way to rapidly obtain desired genetic changes directly in elite crop cultivars. I will discuss advantages and hurdles in the use of protoplasts and present the successful application of this methodology in the production of gene-edited cassava lines.
Leader, Applied Science and Technology at Corteva
Talk Title: "Developing Improved Crops Using Genome Editing"
Abstract: Recent breakthroughs in reference genomics, plant regeneration, and CRISPR/Cas enable plant genome editing for crop improvement. We have developed a cutting edge toolkit, including methods for elite line plant regeneration, novel methods for characterizing off-site cutting and characterization of a number of novel Cas9 orthologues with diverse PAM sequences. We are using plant genome engineering to improve a number of high value crops by improving yield potential, changing grain composition, and enhancing disease resistance. Our most advanced genome edited product, CRISPR-Waxy corn, has successfully completed the development process in less than four years.
Professor at the University of Minnesota
Talk title: “Overcoming Bottlenecks in Editing Plant Genomes”
Abstract: Plant gene editing is usually carried out by delivering reagents such as Cas9 and sgRNAs to explants in culture. Edited cells are then induced to differentiate into whole plants by exposure to various hormones. Creating edited plants through tissue culture is often inefficient, requires considerable time, only works with limited species and genotypes and causes unintended changes to the genome and epigenome. We have been pursuing alternative approaches for plant gene editing that minimize or obviate the need for tissue culture. In one approach, we generate gene edited dicotyledonous plants through de novo meristem induction. Developmental regulators and gene editing reagents are delivered to somatic cells on whole plants. Meristems are induced that produce shoots with targeted DNA modifications, and gene edits are transmitted to the next generation. In a second approach, we use RNA viruses to deliver sgRNAs through infection to transgenic plants that express Cas9. The sgRNAs are augmented with sequences that promote cell-to-cell mobility and movement into the meristem. Gene edited shoots are thus generated that transmit gene edits to the next generation. Because both approaches minimize the need for tissue culture, they promise to help overcome this bottleneck in plant gene-editing.
Professor, Co-Director of GES Center at North Carolina State University
Talk Title: “Regulation and Governance for Genome Editing in Plants: Understanding the past and moving forward towards a more publicly-robust future”
Abstract:This presentation will briefly review the history of oversight for genetically modified (GM) plants, its strengths and weaknesses, and historic policy dynamics. Then it will consider recent changes under new U.S. regulations for GM crops that were promulgated in 2020. Current regulatory pathways for gene-edited crops will be described, along with where there are opportunities or deficits for the provisioning of public information or independent scientific input. It will evaluate these current U.S. regulations according to principles of good governance derived from the social science, ethics, and risk governance literature. Frameworks for better governance of gene-edited crops will be discussed as possibilities for moving forward in ways that are better positioned to engender public confidence and legitimacy, and possibly trust. Finally, barriers to implementing good risk governance and responsible innovation will be presented to spark a discussion of what is a realistic versus idealistic path forward.