Argentina sows the first potato that do not oxidize

After editing the gene and obtaining tubers without enzymatic browning, a team of researchers from the institute advances with the cultivation of the first field trials of selected lines. These results will generate the necessary data to multiply the plants and, in the future, register the variety in the Argentina National Seed Institute (INASE).

Polyphenol oxidases (PPO) are responsible for the process known as enzymatic browning - they alter the color, taste and texture of the tuber. They are what catalyze the conversion of phenolic substrates into quinones, which leads to the formation of dark precipitates in fruits and vegetables, cause undesirable changes in organoleptic properties and influence the loss of nutritional quality.

In a work published recently in the Frontiers in Plant Science magazine, scientists from Argentina and Sweden reported the results of the research that consisted in the edition of a polyphenol oxidase gene in potatoes (Solanum tubersoum L.), which express mostly in tuber. After successfully editing that gene, they obtained tubers free of enzymatic browning.

In potato, oxidized polyphenol are encoded by a gene family with different expression patterns in the plant. As stated in the publication, the “results show that the CRISPR / Cas9 system can be applied to develop transgene-free potato varieties with reduced enzymatic browning in tubers, through the specific edition of a single member of the gene family "

And while there are several genes that code for the same type of protein, “the strategy we followed was to edit a polyphenol oxidase gene responsible for most of the activity of the protein in a tuber,” said Matías González, a doctoral fellow of Conicet who works at INTA (National Institute of Agricultural Technology, Argentina) Balcarce –Buenos Aires–.

In this way, it would be possible to affect the protein present in the tuber and not the function of other proteins of the polyphenol oxidases family in the rest of the plant.

Polyphenol oxidases (PPO) are responsible for the process known as enzymatic browning - they alter the color, taste and texture of the tuber.

Sergio Feingold, director of the Agrobiotechnology Laboratory of INTA Balcarce, specified that the publication “realizes that the phenotype works. This was verified through the growth of the plant and the harvest of the first potato tubers, which were obtained in a chamber under controlled conditions ”.

According to González, author of the article together with Feingold, Gabriela Massa (INTA-CONICET-UNMDP), Leonardo Storani (INTA-CONICET), Cecilia Tenth Oneto (INTA), Mariette Andersson, Helle Turesson, Niklas Olsson, Ann-Sofie Fält, Per Hofvander (Swedish University of Agricultural Sciences, Sweden), could confirm that "the edition we generated occurred only in the gene chosen as white".

With the approval of the National Agricultural Biotechnology Advisory Commission (Conabia), the sowing tests began that “will allow the plants to multiply to test the campaign that comes with the objective of generating data to register the variety in the INASE ” he said. Feingold

In addition, in the field trial they will observe the selected lines in the context of normal production, allowing researchers to analyze other morphological aspects of the plants obtained.

In a large number of the potato lines they obtained, it was confirmed that the gene was affected in the four alleles. "Since the potato is tetraploid, that is, it has four copies of each of its genes, it is necessary to inactivate all copies of the gene to obtain the desired phenotype," Gonzalez said.

The published work is part of the results of the doctoral thesis that Matías González has been carrying out in a potato gene edition since 2016 under the co-direction of Feingold and Massa, who was able to train in Sweden in the application of CRISPR / Cas9, thanks to the BECAR program.

Editor's note: This article was originally published in Spanish. This English summary has been prepared with Google Translate and edited for clarity.