Innovation in genomic editing of tropical corn can accelerate agricultural research in Brazil

An article published in the journal, Frontiers in Genome Editing, at the start of December revealed the development of a corn genetic transformation protocol based on the use of ″morphogenic regulators″ for plant strains suitable for tropical conditions. The new protocol, considered an important advancement in accelerating the genome editing of corn plants for tropical regions, was developed by researchers at the Center for Genomics Applied to Climate Change (GCCRC), and is an initiative launched by Embrapa and Unicamp, and funded by Fapesp.

Photo: Rafaela Duarte/GCCRC

In general, tropical corn strains do not respond as efficiently to the genetic transformation process necessary for genome editing experiments. The product of the new study was three times more efficient in such strains when compared to the model protocol, which is based on strains developed for temperate climate conditions.

Genome editing in agriculture is considered a powerful tool in the face of climate change, as it allows, for example, the faster development of agricultural varieties that are more tolerant to drought, diseases and a lack of nutrition. The study by the center was carried out with plants for proprietary and public use, which will facilitate access to new research.

Currently, the four largest corn producers in the world are the United States, China, Brazil and Argentina. In 2023, Brazil became the largest exporter, supplanting the United States. The tropical region accounts for 30% of global cereal production. However, corn productivity in tropical regions is significantly lower than in temperate areas.

According to the article's authors, this disparity is due to challenges such as low soil fertility, pest infestations and rain-dependent cultivation, worsened by a history of fewer recent genetic improvements compared to temperate corn varieties.

The corn lines used as study models were mainly from temperate regions, whose outcomes in field tests in Brazil were not not satisfactory. ″These plants are not adapted to the tropical climate, and, therefore, do not perform as well in these regions,″ said José Hernandes, author of the study who drafted the research during his post-doctoral internship at the genomics center.

Another barrier in corn editing processes is the low efficiency of traditional genetic transformation protocols. Transformation is a method by which external DNA, which, in this case contains genes that promote genome editing, is introduced into cells, allowing the expression or alteration of specific genes.

During the research, the authors explored a new molecular biology strategy that showed great promise in corn transformation, which us the use of genes that stimulate the regeneration process of transformed plants, the so-called ″morphogenic regulatory genes.″

″The protocol we used, developed by our collaborator Laurens Pauwels in Belgium, was prepared for a temperate strain and worked very well for more than half of tropical ones we tested,″ said researcher Ricardo Dante from Embrapa Agricultura Digital, one of the authors of the study.

Three of the five tropical strains were successfully transformed using the morphogenic gene expression strategy, reaching efficiency rates three times higher than the average of protocols that do not use this strategy, reaching 6.63%.

″We now have a study lineage that is more adapted to local field conditions,″ Hernandes said, referring to strains with high susceptibility to transformation, and the ability to generate healthy and agronomically suitable seedlings for studies in real production conditions in the country.

Brazilian public institutions at the forefront

Another concern of the group of researchers was carrying out the tests using Brazilian commercial strains and non-proprietary strains simultaneously. The latter came from the International Corn and Wheat Improvement Center (CIMMYT), a Mexico-based organization that conserves corn germplasm. The genomics center became the national repository of some strains from the germplasm collection of the Mexican center in Brazil. Any institution wishing to use this material can contact the center.

″It is important for public institutions to lead this process, so everyone can have access to the knowledge generated,″ said researcher Juliana Yassitepe from Embrapa Digital Agriculture, another author of the study.

According to the authors, the results of the study expand the current availability of plants that can be successfully genetically edited, which will accelerate biotechnology research in the country. ″Now that we are able to edit and transform tropical corn, we will test genes developed by the center more quickly and under field conditions,″ Yassitepe explained. The center's main focus is the development of drought-tolerant corn lines.

The research, which was funded by Fapesp, is the result of the center's partnership with Vlaams Instituut voor Biotechnologie (VIB) from Belgium, and with visiting researcher Sofya Gerasimova from the Institute of Cytology and Genetics, the Russian Academy of Sciences and the Novosibirsk State University in Russia. It was also supported by Fapesp.