tomatoes in the greenhouse

CRISPR/Cas9 Technologies

Many scientists believe that humanity is headed for a food shortage that has to be prevented as effectively as possible, by using and improving the CRISPR/Cas9 gene editing technologies that are available today. At the current growth rate, population increase can lead to the planet’s future agricultural demands becoming too great to address.

A recent breakthrough made by plant geneticists at the Cold Spring Harbor Laboratory (CSHL) in New York has led to the ability to improve agricultural crops in an entirely new way through the use of CRISPR gene editing technology.

Using a tomato plant as their main test subject, the scientists managed to separate and alter gene expressions in order to modify three separate traits associated to the plant’s growth and development: size, shape and branching architecture. The method is expected to work for all crops, and could be the basis for an entirely new way of growing food in the future.

A Revolutionary Method Using CRISPR/Cas9 Gene Editing 

The main problem that had yet to be resolved in the past was the lack of enough genetic variety for breeders to use in most species of crops. Using CRISPR technology, this limitation has been overcome, and as Professor Zachary Lippman, the lead researcher at CSHL has pointed out, it is now possible to create crop improvements at a faster rate, while keeping outcomes predictable.

Past methods of genetically modifying crops revolved around the slow process of alteration and adding new, gradual improvements each year. Through CRISPR/Cas9, the researchers at CSHL claim to have perfected a method that bypasses that approach, and directly generates the necessary variants that control the specific gene activity responsible for all yield barriers.

Supported by the NSF and a Pew Latin American Fellowship, the experiments conducted at CSHL applied the use of CRISPR “scissors” designed to alter gene sequences known as promoters, which are responsible for regulating how and when yield genes are activated. The goal was to generate multiple sets of mutations in these areas, in order to target the three aforementioned aspects of the plant that can regulate crop yields.

The CRISPR technique has demonstrated an ability to fine-tune each of the traits very subtly. It helped to generate new trait and genetic variation that could be used to adjust the plant’s yield quite accurately. As Lippman explained, the method allowed each of the traits to be controlled almost as easily as turning a fine dial.

The researchers at CSHL have proven that a more subtle impact can be obtained on quantitative traits without requiring the deletion or inactivation of specific proteins. Instead, CRISPR/Cas9 offers a more flexible alternative that fine-tunes gene expressions, making all the necessary modifications much faster.

Artificially Generated QTL

Finding QTL (quantitative trait loci) has been one of the major goals of many researchers throughout the years. The name describes the mutated areas generated by various genetic adjustments. QTL occurs in nature as a result of rare and spontaneous mutations, however, exploiting them can be a much more difficult matter without genetic modification – which is why plant breeders have been having difficulty with QTL for centuries.

CRISPR-generated QTL is much more versatile. Aside from the more precise changes it brings about, it can also be combined with naturally occurring QTL to build so-called toolkits of genetic variation that can be controlled more easily, and that may lead to an easier improvement of specific crop yields according to desired specifications.

Founded more than 100 years ago, having housed eight Nobel Prize winners, and having been a leading research center for advances in contemporary biomedical research, the Cold Spring Harbor Laboratory hopes to continue this research in the years to follow and unlock more secrets involving the use of CRISPR/Cas9 technology for significantly increasing crop yields.

 

Further Reading

Cold Spring Harbor Laboratory. “Plant geneticists develop a new application of CRISPR to break yield barriers in crops: Mutating regulatory regions varies yield traits ‘the way a dimmer switch controls a light bulb’.” ScienceDaily. ScienceDaily, 14 September 2017. <www.sciencedaily.com/releases/2017/09/170914152355.htm>.
Daniel Rodríguez-Leal, Zachary H. Lemmon, Jarrett Man, Madelaine E. Bartlett, Zachary B. Lippman. Engineering Quantitative Trait Variation for Crop Improvement by Genome EditingCell, 2017; DOI: 10.1016/j.cell.2017.08.030