Effective editing
Ten years ago, the new CRISPR-CAS9 technology allowed scientists to change the genetic code of living organisms. But the original method could perform one function: the removal or replacement of genes in the genetic sequence. Later modifications of CRISPR allowed scientists to change the expression of genes, turning them on or off, but not removing them from the genome. Each of these functions could only be performed separately.
A research team from the University of Maryland College of Agriculture and Natural Resources has developed a CRISPR Combo - a method of editing some genes while changing the expression of others. This new tool will enhance the functionality of genetic engineering.
The group developed a new modification of CRISPR-Combo to regulate expression and simultaneous editing of several genes and proved that it performs both these functions of genetic engineering in parallel without negative consequences. The researchers demonstrated this using tomato cells by knocking out one gene (gene A) and activating another (gene B) without accidentally crossing and knocking out B or increasing the activity of A.
Then the authors tested the CRISPR-Combo on the favorite object of genetic engineers – arabidopsis. They edited a gene that makes the plant more resistant to herbicides, while activating a gene that causes early flowering. The result was a herbicide-resistant plant that produced eight generations in one year instead of the usual four.
The results were confirmed on other plants. In poplar cells, the researchers edited several traits and activated three genes that promote the regeneration of plant tissues. The result is a plant capable of developing from tissue (cuttings), and not just from roots or seeds.
On the left – poplar sprouts with an edited herbicide resistance gene, on the right – with also enhanced expression of regeneration and growth genes.
With the help of CRISPR-Combo, it was also possible to obtain rice from tissue cultures that did not require hormonal supplements. They expressed more of the edited gene protein than the tissues created with the addition of hormones, which are currently used to grow genetically engineered plants from tissue cultures.
The CRISPR-Combo method will soon be tested on citrus fruits, carrots and potatoes.
Article C.Pan et al. Boosting plant genome editing with a versatile CRISPR-Combo system is published in the journal Nature Plants.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of the University of Maryland: New CRISPR-combo boosts genome editing power in plants.