Breeding gene-edited crops that weather climate change

The trend was documented in a peer-review study published in the British magazine GM Crops & Food by Dr. Miguel Ángel Sánchez, executive director of ChileBio.

Chile currently exports GM corn, soybean and canola seeds, with the United States, Canada and South Africa its main clients. On the research side, however, a number of different GM cereal, vegetable and fruit crops are under field trials, including many developed through gene editing tools like CRISPR.

'Legal void' and regulatory paradox

Despite the excellent regulatory environment for seed and research activities, Chile lives in a paradox that I wrote about in a previous column in 2016. On the one hand, the country provides R&D and multiplication services for GM seeds, and the countries that take advantage of and plant these seeds sell us the harvested grain for use in our food industry or animal feed. But Chilean farmers still can't use the same technology for domestic/commercial purposes. Chile also imports soybeans and corn from neighboring countries that are top producers of GM crops, such as Argentina and Brazil.

This situation leaves Chilean farmers at a disadvantage compared to their colleagues in the region, where six South American countries take advantage of bioechnology for commercial use. A 2006 bill would allow GM crops to be grown commercially, but it has been sleeping for long years in Congress.

"Despite the fact that Chile imports food derived from GM crops for human and animal consumption without restrictions, the country doesn't have clear procedures to produce GM crops in unconfined areas for use in local agriculture, for example," Sánchez told the Alliance for Science. "This inconsistency is primarily because the use of GM crops in unconfined areas is under the scope of other incomplete regulations."

Chile's Environmental Bases Law states that to obtain authorization to use GMOs in unconfined areas, an application must be submitted to the Environmental Impact Assessment System (SEIA). But after 10 years, no protocol or procedure has been implemented that indicates what information should be delivered to the SEIA, the times that the evaluation could take, the people or teams responsible, the criteria, etc., Sánchez explained.

CRISPR and the pressure of climate change

Though it has lagged in adopting regulations that allow for domestic use of GMOs, in 2017 Chile became the second country in the world, after Argentina, to implement a regulatory approach for plant products obtained through new biotechnological breeding techniques (NBTs), including the popular CRISPR technique.

The SAG established a "case by case" (product-by-product) consultation process to determine if a plant variety as final product obtained through NBTs contains external genetic sequences (transgenes). If no transgenes are present, the crop is not subject to the GMO regulations and the SAG must deliver an official response through a legal resolution within 20 business days.

"So far, the SAG has received eight requests for pronouncement to determine whether or not specific vegetables developed through biotechnology are GMOs," Sánchez said. All were determined not to be GMOs.

The eight crops improved by techniques such as CRISPR and TALEN are described in Sánchez's recent study and include canola with silique shatter resistance, camelina and soybeans with a change in fatty acid composition, as well as maize with drought tolerance, increased yield and change in starch composition.

Apart from regulatory streamlining, there are other important factors that can accelerate the use of this latest genetic improvement technology and its adoption by Chilean farmers: the serious climatic effects that the country is experiencing.

The country's public institutions are deveoping a range of crops genetically edited for advantages such as tolerance to drought or salinity, which are a big tool in addressing the worst mega-drought in the country for over a decade, as well as the increase in soil degradation. This problem has required the government to allocate substantial emergency funds to thousands of farmers and ranchers who have lost their crops and don't have forage for their animals.

'Made in Chile' biotechnology developments

Between 1991 and 2013, the State of Chile invested more than $16.2 million in 32 projects for the development of GM crops, of which half were conducted by INIA and the remaining half by universities and foundations. These include various vegetables, cereals and fruit trees with traits like resistance to biotic and abiotic stress, as well as better nutrition and product quality.

At the university level, drought-tolerant corn was developed in the laboratory of Dr. Simón Ruiz of the University of Talca using drought and salinity tolerance genes taken from Solanum chilense, a small native tomato from the Atacama Desert.

In field trials, the modified plants received no water for 52 days, yet they managed to maintain 80 percent of their total productivity, compared to just 20 percent for the control plants. This remarkable result hasn't been achieved by any other research group internationally.

The laboratory led by Dr. Patricio Arce at the Catholic University of Chile in Santiago is working on the development of salinity-tolerant citrus GM rootstocks. These have already been successfully evaluated in field trials in the Copiapó Valley, which has some of the most saline soils on the planet. If it reaches the commercial level, the fruit obtained wouldn't be a GMO, since the rootstock, or plant pattern, is the genetically modified structure and a conventional non-GM variety of interest would be grafted onto it.

Dr. Patricio Arce, left, in field trials of GM citrus rootstocks in the Copiapó Valley. Dr. Simón Ruiz, right, in field trials of drought-tolerant corn in Talca. Image: Explora.cl and University of Talca

Other research carried out in Arce's laboratory includes a GM tomato vaccine against cholera and hepatitis, an extensive breeding program of table grapes using conventional and biotechnological techniques and a non-browning, gene-edited lettuce that could reduce food waste.

An ambitious and more recent project is led by Dr. Claudia Stange, from the University of Chile, in association with INIA and Arturo Prat University. Its main objective is the use of CRISPR to develop tomato and kiwi rootstocks tolerant to drought and saline soils.

Dr. Claudia Stange (left) and Dr. Francisca Castillo (right) in greenhouse experiments with gene-edited tomato and wheat plants, respectively. Images provided by both researchers.

"Tomato and kiwi crops are very relevant to the country's economy," Stange told the Alliance for Science. These two projects could take four years from gene selection to field evaluation, according to Stange.

Stange's laboratory is also conducting pioneering research that seeks to develop apples edited with CRISPR that achieve higher levels of beta-carotene (a molecule that our body uses to form vitamin A) and reduce the browning produced by cutting the fruit.

"At the end of the year we will be able to have the first plants to be transferred to Los Olmos nursery, where they will continue the evaluation in the greenhouse and field," Stange said. "In the meantime, our team will continue to generate and select more lines in order to have a quantity of plants that allows us to choose the best one when they produce fruit."

Austral University of Chile (UACH), located in the city of Valdivia, is pursuing biotechnological improvement projects focused on wheat. Dr. Daniel Calderini's laboratory works on the development of GM wheat of higher grain yield through a higher expression of expansins, the proteins that allow the lengthening of plant cell walls.

At the same institution, Dr. Francisca Castillo leads a research project — also conducted with public funds — that uses CRISPR to study candidate genes that are useful in achieving heat-tolerance in wheat.

"Our project aims to elucidate the role of the rotamase enzyme gene in heat-tolerance processes in wheat, and we hope it constitutes useful information to mitigate the effects of heat shock events on wheat yield and contribute to face the problems associated with the global increase of temperature, through the generation of varieties more adapted to climatic conditions," Castillo told the Alliance for Science.

Castillo emphasized the importance of investigating the performance of wheat crops in the current climate change scenario, as it is one of the most consumed cereals in the world and is being negatively affected by heat shock events.

The INIA, which has probably carried out the most crop breeding using biotechnology in Chile, is continuing its research in various crops and fruit trees. In recent years, it has advanced with lines of research in gene-editing through CRISPR.

"The projects in which we have been involved have allowed us to generate grapes with fungal resistance and cherry trees that need less cold hours for their flowering," Dr. Humberto Prieto, principal researcher of agricultural biotechnology at INIA, told the El Sur newspaper. He said that using all available plant breeding tools is "the only way to generate new plant varieties which will allow us to sustain ourselves in a crisis scenario."

Although Prieto's laboratory has worked on fungus resistant experimental GM grapes, they recently developed a technological platform in association with the Biofrutal Consortium to achieve the same objective through gene-editing, which could actually result in domestic/commercial use in the field.

Prieto also leads INIA projects on gene-editing in rice and potato to study yield genes and susceptibility to pathogens, as well as the development of gene-edited potato lines that don't present induced sweetening under cold storage.

Biotechnology for climate adaptation, better nutrition and agro-sovereignty

Local researchers agree that modern biotechnology offers tools that can help agriculture adapt to the challenges of climate change and develop more sustainable crops and farming systems.

"In this context, unlike traditional breeding techniques, biotechnological techniques allow us to perform genetic improvement safely and more precisely, changing only the traits of interest, without affecting other genes, and the results are obtained in considerably shorter times," Sánchez said.

"In this way, agricultural biotechnology and these tools represent a great opportunity to foster innovation and offer alternatives to contribute to making agriculture more sustainable," he added. "This means that through obtaining new plant varieties adapted to different conditions, we can produce more food on less land, reducing losses in the field and food waste, obtaining food of nutritional quality, being more friendly to the environment, reducing the amount of inputs and facing environmental fluctuations such as drought, cold, etc."

Stange emphasized the importance of modern biotechnology in contributing to a healthier diet and serving as a tool that generates local products with added value that are 100 percent adapted to the national agricultural and climatic reality.

"Currently, the new varieties are acquired by paying royalties to foreign companies," she explained. "This implies bringing in those varieties and waiting a few seasons until they adapt to our edaphoclimatic conditions — and with the expectation that they will produce the fruits as they are produced where they were generated. This is a risk. In our case, these are varieties already produced and marketed in Chile, to which we will add these new traits. In this way, we will add value to the Chilean varieties of apples."

"It's relevant to generate varieties made in Chile that are also healthier," Stange added. "Today's consumers are looking for foods that are functional, with a higher content of antioxidants, vitamins, etc. Those characteristics would be fulfilled by our apples with the highest content of carotenoids, which are provitamin A molecules, and antioxidants that counteract various diseases and aging."

Castillo describes biotechnology as an advanced tool that allows the study of candidate genes that can assist breeding programs. "We are in a genetic revolution, and as scientists we can create innovative research solutions to face one of the greatest global challenges in food security through an agriculture transformed by new technologies."

Source: Ag News
Photo by Markus Spiske on Unsplash

Source: Ag News