As things change, they ultimately stay the same. Or perhaps a better metaphor is that we always end up circling back to the beginning, retracing our own footsteps. That seems to be the case today, though not in a bad way.
The Early Bloom
One of the very first original biotech experiments back in the 1980’s was a modest one. The change would have no real effect on the world, much like the item itself. What we’re talking about here are ornamental flowers. Pretty to look at and have around the house and certainly an industry that makes a fair amount of money. But, overall, not something of particular consequence.
In those early days of genetic modification, scientists were still exploring what these new techniques were capable of. Changing the color of ornamental flowers to ones that aren’t normally seen in the cultivar seemed like a worthy enough endeavor. Crossing over a gene from corn into petunias to make them orange was fun, as was the later creation of the first commercially sold biotech plant, the Blue Carnation, in the 90’s. We’ve discussed that one before.
Last year in said discussion, Bioscription mentioned that we were likely to see new CRISPR-based varieties of ornamentals be created, since the tech allows a lot more diversity than the original methods were capable of. And that time has indeed come.
Researchers at Japan’s University of Tsukuba were assigned a task by the National BioResource Project to alter the genome of one of Japan’s two traditional model plants. The one they were given was the Japanese morning glory (Ipomoea nil). While it is technically a plant endemic to China, it was brought over to Japan in the 8th century and later became a common household variety. Thanks to a recent high quality sequencing of its genome, the scientists had free rein to choose the precise change they wanted to enact.
As a side benefit, the purpose of the project was to create an altered version of the flower available to the public in an effort to increase general scientific literacy of biotechnology and reduce fearmongering claims surrounding the field.
Prior to the start of this experiment, previous studies had prepared expression sequence tags to mark the genome where any selected change is to occur and they also had put together bacterial artificial chromosomes (BACs) to house any required genetic material to be utilized.
Precision Color Testing
For their particular test, the researchers focused in on the gene for dihydroflavonol-4-reductase-B (DFR-B), an enzyme involved in anthocyanin synthesis. If disrupted, the lack of the enzyme would alter the resulting color of the plant’s stems and flowers. Using the BACs with the CRISPR system inserted, they were placed into Rhizobium bacteria as a mediator to transfer them into the plant cells.
A concern for the experiment was whether CRISPR would accurately showcase its famed precision capabilities or not, as the DFR-B gene is located very closely to two other related genes and any alteration or misplacement would affect those instead. Add onto this that plants are not always successfully transformed with CRISPR changes and there was the possibility of requiring many attempts to succeed.
But, in their first batch of secondary embryos (plants that have only undergone two cell splitting cycles from the original embryonic cell), 32 of the plants were successfully transformed and exhibited the traits expected for the selected marker. Of those, 75% continued on to show the expected loss of anthocyanin-related pigments. Rather than having purple stems and flowers, as the wild-type exhibits, these modified morning glories had green stems and pure white flowers.
When sequenced after, they found no alterations other than the inactivation of the desired gene for the anthocyanin enzyme. This high efficiency and accuracy of CRISPR once more shows its abilities. It also demonstrated that the highly specific protospacer adjacent motif (PAM) sequence used to guide the CRISPR system is indispensable for ensuring no mistakes occur.
This is also the first attempt at using CRISPR to alter flower color and has helped to investigate how color biosynthesis pathways connect to each other thanks to the enzyme inactivation. With this unmitigated success, work on other ornamental flower changes can be started.
And the National BioResource Project has prevailed in showing the safety of biotechnology, along with allowing ensuing discussion on whether CRISPR-altered organisms with no added transgenic DNA, as in this case, still count as transgenic organisms (since genetic modification in many places is included under this banner).
Photo CCs: PharbitisNil from Wikimedia Commons