Precision Gene Editing
In late 2012, a new system for genetic engineering hit researchers around the world by storm. The system is fast, flexible, relatively inexpensive, and, for Dr. Joyce Van Eck and her research team at the Boyce Thompson Institute, it worked on the first try.
Plant scientists often use genetic engineering as a tool to study how genes function and to harness those genes to improve crops. In the past, engineering relied on random insertions of foreign DNA into the plant genome followed by extensive screening to assure that the insertions did not disrupt regions important for development. The new system, called CRISPR/Cas9 genome editing, is targeted so that changes are made in the desired region of the genome. According to Van Eck, “The most exciting thing about working with CRISPRs is that it’s not a hit or miss situation. You get the hits that you want.”
As its name suggests, CRISPR/Cas9 genome editing requires two components. Cas9 (CRISPR associated 9) is a scissor like molecule that can cut double stranded DNA. The CRISPR (clustered regularly interspaced short palindromic repeats) is a sequence designed to guide the Cas9 molecule to the specific site researchers want to edit. Because CRISPR guided engineering does not require the introduction of foreign genes from different species it might be accepted with less controversy than previous engineering strategies.
To our knowledge, Joyce Van Eck’s team along with her collaborators at the Cold Spring Harbor Laboratory and The Sainsbury Laboratory and are the first to report the use of CRISPR/Cas9 to generate tomato plants that contain selectively edited genes. As a proof of concept, the team started by using CRISPRs to target a developmental gene to make mutants referred to as wiry, easily recognized by their wiry or shoestring-like leaves (see photo). Their publication was accepted by Plant Physiology and can be accessed here. The Van Eck group is now using the CRISPR technology as part of an NSF funded project with two groups at Cold Spring Harbor Laboratory to identify genes that could potentially increase yield.
Since the first CRISPR-mediated editing report in 2012, researchers have used CRISPR guided genome editing in humans and mammalian models to target genes responsible for HIV, sickle cell anemia, cystic fibrosis, and autism with the hope of developing targeted cures. The establishment of this technology in tomato opens doors to new and exciting research opportunities at the BTI and will help advance our mission of improving agriculture, protecting the environment, and enhancing human health.