Fried green, or red and homogeneous tomatoes

Researchers search for ways to adapt plants to climate change.

By Enrique Sánchez Agrifood journalist

How do you like your tomatoes? Green, red, ripe, big …? It’s up to producers to satisfy consumer concerns and tastes. To do so, they rely on the work done by scientists and research centres. This work makes it possible, among other things, to delay the flowering of the tomato, which can grow steadily in the fields with faster flowering or achieve a higher yield. These are some of the applications that CRISPR / cas9 offers the fruit and vegetable sector. To understand this biotechnology tool, I recommend that you take your time and read this article several times, since the technique is quite complex.

I suggest you use your imagination and a little lab work. Take a tomato plant and extract its DNA. Then use some scissors with GPS. The geolocation system will show you exactly where to cut. Make the incision in the gene to make it immune to pests and diseases. It may sound like science fiction and it is complicated to explain and understand without some knowledge of genetics and familiarity with terms such as DNA, RNA, enzymes and proteins. But this imaginative exercise has already been achieved in Spanish laboratories such as the National Biotechnology Centre, in European countries and also in the United States. The technique is called CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats).  The acronym stands for to a well-known biotechnology tool within new therapeutic strategies that was discovered in 2005 by Spanish researcher Francisco Javier Mojica at the University of Alicante when analysing the salt flats of Santa Pola.

The advance of science is unstoppable, and this genetic engineering tool is now used to treat diseases. Simplifying the arguments of the scientific community, CRISPR /cas might be defined as the union of DNA with RNA in a bacterium to make it immune. The proteins, called Cas, can pick up a part of the DNA, modify it and reassemble it into the genetic sequence. This immunity to bacteria can make plants bigger, heavier, more resistant or change their pigmentation. A more accurate guide prepared by the Antama Foundation has been available for download from its website since March. The tool can be summarised as follows: “When a virus infects a bacterium, its DNA fragments and it is included in the microorganism’s genome, producing small RNAs that act as CRISPR guides enabling the system to recognise and destroy the DNA of the virus in a subsequent infection”.


Producing food that can adapt to climate change

The scientific community ensures that gene editing is a cheap, accurate and simple technique. That works in all organisms in which it has been tried so far. It is possible to inactivate a gene, edit it with new sequences, correct mutations or even insert new mutations to boost production or profitability. In addition, several scientists say it can solve some adaptation problems caused by climate change.

Since the purpose of this article is to explore this tool’s applications in the horticultural sector, let’s look at the opportunities it will offer producers in the coming years. This is a time of great challenges and opportunities when it will be necessary to increase food production to meet demand from the population for quality food that is able to adapt to climate change.

One example, and continuing with the tomato, we ask ourselves the following question: How many vegetable growers have had to deal with high temperatures and the stress that lack of water causes to plants? Sometimes the fruit does not succeed and sometimes it does not ripen. CRISPR is able to inactivate the gene so that the fruit grows without pollination. This test has shown a higher yield is obtained, that tomatoes contain more sugar and are heavier. All of them have been grown under thermally stressful weather conditions. These findings were announced several months ago by researcher Manuel Piñeiro, INIA’s head scientist at the Biotechnology and Plant Genomics Centre. He did so during a presentation entitled “Advances in biological engineering: gene editing and its use in crops” during a seminar organised by APAE and the Agrarian Forum Foundation, last February.

A similar opinion has been presented at several conferences by Lluís Montoliu, a CSIC researcher from the Department of Molecular and Cellular Biology, since 2016, the year in which he began to disseminate it within the scientific community. He explains that the CRIPSR /cas9 “allows us to modify plant and animal genomes in ways we had not dreamed of just four years ago”. This technique makes it possible to obtain genetic variations of plants for transfer to others, he adds. For example, if we have two tomatoes and one of them has special characteristics, the laboratory can detect it and discover which genetic variations make them occur. They use the information to reproduce them in another tomato.

This tool can act several genes of the plant simultaneously. This is a breakthrough if the ultimate goal is to increase farm production and profitability. For example, you can edit the gene that regulates size or the floral organs. This obtains bigger tomatoes with more flowers, for a greater number of fruits per plant and a better yield.

Despite having discovered the technology in our country, it is on the other side of the Atlantic, in the United States, where research with CRSPR /Cas9 is more advanced. An example is the genetic engineering company Cellectis, in Minnesota. One of its researchers, Dan Voytas, has managed to ensure that a Ranger Russet potato does not build up sugars when stored chilled. This means it lasts longer, and when the potato is fried, a potentially carcinogenic substance, acrylamide,  does not appear. The study ended in 2015 and could soon be marketed. Other American research is searching among the letters that make up the mushroom genome. The aim is to delay the product turning brown. This would stop the mushrooms from turning an unpleasant colour that puts consumers off buying them.


Genetic editing and non-genetically modified organisms

These days, thanks to scientific advances, this technique has been used on about fifty occasions in which the last five years. Proof of the strength with which the CRISPR /cas9 is advancing is that large global corporations in the agricultural sector, have made a great effort to hire researchers and use gene editing, thus far only in cereals. Monsanto and DuPont have acquired rights over several research projects. As they advance, they say they are already growing corn and wheat with this technique. Some have announced that their products could be on the market “very soon”.  We are talking about shorter than five-year terms.

Considering the path behind all the research and its “almost infinite” applications, the scientific community only has one question that concerns them.  Will gene editing meet the same fate as transgenics? This seems to be the only threat against CRISPR /cas9. They are clear about it and their answer is that with this editing tool no changes are produced or introduced into the genome derived from other organisms. “No new genetic material is introduced, rather the result is variation of original plant,” they say. 

According to the scientists, CRIPSR cas9 is “amazingly accurate” and “it’s here to stay”. They say that the only limit is that of the researchers’ imaginations. And I add. The same goes for the way that the tool is communicated and used. We all need to ensure that we inform consumers of its benefits. Increasing profitability for producers, higher production to meet the demand for food and increasing the variety of products for filling our shopping baskets. It remains to be seen how scientists will transmit their wisdom and knowledge to food producers to convince them of the opportunities for the sector and the industry in general with these new tools.  What is certain is that this acronym is being heard increasingly more frequently, and that it will give us a lot to talk about in the near future.