CRISPR has taken the genome engineering world by storm owing to its ease of use and utility in a wide variety of organisms. While much of current CRISPR research focuses on its potential applications for human medicine (1), the potential of CRISPR for genome engineering in plants is also being realized. There are a variety of reasons to consider using genome editing to change the genetic code of plants, including the development of crops with longer shelf life and the development of disease-resistant crops to increase agricultural yield (2,3). While it is certainly possible to select for desirable traits using traditional plant breeding approaches, these techniques are cumbersome, often requiring several rounds of selection to isolate plants with the phenotype of interest. Genome engineering, on the other hand, allows for targeted modification of known or suspected genes that regulate a desired phenotype. In fact, CRISPR has already been used to engineer the genome of many plant species, including commonly used model organisms like Arabidopsis and Medicago truncatula and several crop species including potato, corn, tomato, wheat, mushroom, and rice (4). Despite the almost universal functionality of the CRISPR system in most organisms, some plant-specific changes to CRISPR components are necessary to enable genome editing in plant cells.
As previous blogs have noted, plants are an important foundation for life on Earth. Selective breeding methods have shaped the plants that we grow and eat, and genetic engineering will continue to improve plant nutrition, yield, and pest resistance. Much of plant genetic engineering revolves around Agrobacterium tumifaciens. Agrobacterium carries a “tumor-inducing” or Ti plasmid, which allows it to transfer genetic material into the host plant genome. Scientists have worked to optimize this system for gene transfer, studying the stability of modified Ti plasmids during plant infection, as well as plasmid yield during preparation in E. coli. Addgene depositor Indu Maiti has created a new and versatile binary Ti vector for both transient and stable gene expression applications in plants. This smaller, easily customizable vector functions in multiple species, including tobacco and Arabidopsis.
This post was contributed by Nikolai Braun and Keira Havens, co-founders of Revolution Bioengineering. Read their previous blog post about how they started their company here.
The first transgenic plant was engineered over 30 years ago, but plant synthetic biology is still in its infancy. A long timeline from transformation to testing and a lack of well-characterized genetic tools make it challenging to engineer a specific function in these multicellular organisms. However, the rewards are great if you take the plunge – plants are the foundation of life on earth, and opportunities abound to build better fuels, feeds, foods, and fibers. And because working with plants can be challenging, there are a lot of unexplored areas in plant biotechnology that are ripe with opportunity. We’ve decided to jump into one of those unexplored areas with our color-changing flower, but to do that we’ve had to navigate the challenges involved in plant synthetic biology.
Nicola Patron is Head of Synthetic Biology at the Sainsbury Laboratory, where she often feels more like an engineer than a biologist. Their focus at the lab is on plant-pathogen interactions, and her aim is to produce constructs and edit genomes so as to make plants, and agricultural crops in particular, resistant to disease. They also devise biosensors designed to elucidate the molecular interactions that go on between plants and their pathogens.
As Patron explains it, her work has always been focused on gene transfer, from transgenes to plants, chloroplast to the nucleus, or pathogens to their hosts. I spoke with her about what motivates her research, the MoClo Kit she and Sylvestre Marillonnet share with the scientific community via Addgene, the struggles of plant scientists and how they work to overcome them, and why she spends some of her time engaging with others on Twitter, among other things.