Plants tolerant to climatic stresses
Edição XXV | 03 - Mai . 2021 In the coming years, one of the challenges of agriculture will be to meet the demand for food production in view of the increase in population. According to UN projections, the world population is expected to reach 9.7 billion people in 2050, more than 25% compared to the current census. Associated with this, global climate changes point to a scenario in which the occurrence of adverse climatic conditions, such as episodes of extreme temperatures, droughts and floods should be more frequent, bringing serious consequences for agriculture.
Among these abiotic stresses, drought is the one that has attracted the most attention, since water deficiency problems are already part of our present. Brazil is a country with continental dimensions, and agriculture is practiced in its various regions. And, the climatic variations observed in the different regions of the country, make it common for droughts or short periods of summer to occur, enough to impact the productivity of agricultural crops.
Water is essential to the life of all living organisms and it is no different with vegetables. Although it is not possible to develop a plant that produces in the absence of water, some genetic tools can be used to make plants more efficient in the use of water, in order to better tolerate periods of water scarcity, helping to mitigate the impact of drought in the food production. However, developing a drought-tolerant plant or other abiotic stresses is not an easy task. This explains, in part, why most of the technologies available on the market today are aimed at other characteristics, such as herbicide tolerance and insect resistance.
From the genetic point of view, the characteristics of living organisms can be classified as qualitative, which are those controlled by one or a few genes, such as herbicide tolerance, or, quantitative, which, as the term itself suggests, are those controlled by a large number of genes, which include tolerance to abiotic stresses. The greater the number of genes that control a trait, the more difficult its genetic manipulation is. Although it is difficult to work with this type of characteristic, many studies have shown that the use of biotechnological tools for this purpose is promising.
At Embrapa Soja, researchers have been developing long-standing studies in partnership with Jircas (Japan International Research Center for Agricultural Sciences), aiming at the development of drought-tolerant soy plants. The strategy is based on the insertion of regulatory genes, called transcription factors, that control the expression of a large number of genes. Thus, it is possible to obtain individuals more adapted to these stresses and who can be used in the development of strains with complex characteristics of tolerance to abiotic stresses.
Although the process of obtaining transgenic plants with drought tolerance is highly complex, genetically modified corn seeds (GMs) with such purpose, such as the DroughtGard® event (Monsanto, currently Bayer), are already commercialized in the North American market. In Brazil, a novelty is drought-tolerant transgenic soybeans, HB4 soybeans, which are expected to be launched for the 2022/23 harvest, whose technology was developed by the American company Verdeca, a joint venture between Arcadia Biosciences and Bioceres Crop Solutions. HB4 soybeans were approved by CTNBio in 2019 and are being developed in Brazil by Tropical Melhoramento & Genética (TMG), which was also responsible for the deregulation of technology in the country.
By means of classical genetic improvement it was also possible to obtain varieties that present better production stability even under adverse climatic conditions. Recently, the company Corteva announced Optimum AQUAmax technology on the market, corn hybrids that under a water deficit have a productivity 10% higher than that of other products. This technology was developed by means of classical genetic improvement and is already being used in the United States.
More modern biotechnology tools like CRISPR technology can also contribute to the development of stress-tolerant plants. Recent studies have shown that it is possible to improve drought tolerance in maize by editing the ARGOS8 gene, an inhibitor of the ethylene response, which is normally expressed in low amounts. The corn genome editing strategy via CRISPR, by homologous recombination, was used to increase the expression of this gene. As a result, the strains developed survived longer and showed higher productivity in drought conditions. These examples show us the importance of science and biotechnology to bring solutions to agriculture, not only for the problems of the present, but also for the adversities predicted in future scenarios.
Among these abiotic stresses, drought is the one that has attracted the most attention, since water deficiency problems are already part of our present. Brazil is a country with continental dimensions, and agriculture is practiced in its various regions. And, the climatic variations observed in the different regions of the country, make it common for droughts or short periods of summer to occur, enough to impact the productivity of agricultural crops.
Water is essential to the life of all living organisms and it is no different with vegetables. Although it is not possible to develop a plant that produces in the absence of water, some genetic tools can be used to make plants more efficient in the use of water, in order to better tolerate periods of water scarcity, helping to mitigate the impact of drought in the food production. However, developing a drought-tolerant plant or other abiotic stresses is not an easy task. This explains, in part, why most of the technologies available on the market today are aimed at other characteristics, such as herbicide tolerance and insect resistance.
From the genetic point of view, the characteristics of living organisms can be classified as qualitative, which are those controlled by one or a few genes, such as herbicide tolerance, or, quantitative, which, as the term itself suggests, are those controlled by a large number of genes, which include tolerance to abiotic stresses. The greater the number of genes that control a trait, the more difficult its genetic manipulation is. Although it is difficult to work with this type of characteristic, many studies have shown that the use of biotechnological tools for this purpose is promising.
At Embrapa Soja, researchers have been developing long-standing studies in partnership with Jircas (Japan International Research Center for Agricultural Sciences), aiming at the development of drought-tolerant soy plants. The strategy is based on the insertion of regulatory genes, called transcription factors, that control the expression of a large number of genes. Thus, it is possible to obtain individuals more adapted to these stresses and who can be used in the development of strains with complex characteristics of tolerance to abiotic stresses.
Although the process of obtaining transgenic plants with drought tolerance is highly complex, genetically modified corn seeds (GMs) with such purpose, such as the DroughtGard® event (Monsanto, currently Bayer), are already commercialized in the North American market. In Brazil, a novelty is drought-tolerant transgenic soybeans, HB4 soybeans, which are expected to be launched for the 2022/23 harvest, whose technology was developed by the American company Verdeca, a joint venture between Arcadia Biosciences and Bioceres Crop Solutions. HB4 soybeans were approved by CTNBio in 2019 and are being developed in Brazil by Tropical Melhoramento & Genética (TMG), which was also responsible for the deregulation of technology in the country.
By means of classical genetic improvement it was also possible to obtain varieties that present better production stability even under adverse climatic conditions. Recently, the company Corteva announced Optimum AQUAmax technology on the market, corn hybrids that under a water deficit have a productivity 10% higher than that of other products. This technology was developed by means of classical genetic improvement and is already being used in the United States.
More modern biotechnology tools like CRISPR technology can also contribute to the development of stress-tolerant plants. Recent studies have shown that it is possible to improve drought tolerance in maize by editing the ARGOS8 gene, an inhibitor of the ethylene response, which is normally expressed in low amounts. The corn genome editing strategy via CRISPR, by homologous recombination, was used to increase the expression of this gene. As a result, the strains developed survived longer and showed higher productivity in drought conditions. These examples show us the importance of science and biotechnology to bring solutions to agriculture, not only for the problems of the present, but also for the adversities predicted in future scenarios.
