Discovery by researchers from Embrapa Grape and Wine (RS) paves the way for the development of apple trees that need fewer cold days to produce. They discovered the gene's mechanism of action ICE1 in the process of inducing and overcoming plant dormancy, a fundamental step to guarantee fruit production. According to the scientists' hypothesis, this gene functions as a thermal trigger that, when stimulated by the cold, triggers a cascade of responses such as the induction of dormancy, a fundamental process for plants originally from temperate climates to flower and produce fruit.
“This process is so important that research institutions around the world invest resources in studies to try to understand it”, emphasizes Embrapa researcher Luís Fernando Revers, responsible for the team that made the discovery. He explains that the genetic control of dormancy in Rosaceae, the botanical family to which the apple belongs, is a complex process and identifying the controlling genes is a major challenge. “We can use this knowledge to develop new cultivars with lower cold requirements and continue to produce fruit even with the warming observed in recent years”, he explains.
After identifying the gene responsible ICE1, The Embrapa Uva e Vinho team created a hypothetical model explaining how the process of inducing and overcoming dormancy occurs, a fundamental step to guarantee fruit production. The idea of the project was to select and study over seven years two segregating populations of apples from the Epagri Genetic Improvement Program, with different budding and flowering periods, whether late or early. During this period, the research was conducted in two stages: genotyping and phenotyping. The genotyping stage allowed the assembly of the genetic map. Subsequently, the integration of phenotyping data with the genetic map led to the identification of the loci associated with the budding period and the gene ICE1.
Article authorshipThe article Spring Is Coming: Genetic Analyzes of the Bud Break Date Locus Reveal Candidate Genes From the Cold Perception Pathway to Dormancy Release in Apple (Malus × domestica Borkh.) had as authors: Yohanna Evelyn Miotto, Carolina Tessele, Ana Beatriz Costa Czermainski, Diogo Denardi Porto, Vítor da Silveira Falavigna, Tiago Sartor, Amanda Malvessi Cattani, Carla Andrea Delatorre, Sérgio Amorim de Alencar, Orzenil Bonfim da Silva-Junior, Roberto Coiti Togawa, Marcos Mota do Carmo Costa, Georgios Joannis Pappas Jr., Priscila Grynberg, Paulo Ricardo Dias de Oliveira, Marcus Vinícius Kvitschal, Frederico Denardi, Vanessa Buffon and Luís Fernando Revers. |
The article Spring Is Coming: Genetic Analyzes of the Bud Break Date Locus Reveal Candidate Genes From the Cold Perception Pathway to Dormancy Release in Apple (Malus × domestica Borkh.) had as authors: Yohanna Evelyn Miotto, Carolina Tessele, Ana Beatriz Costa Czermainski, Diogo Denardi Porto, Vítor da Silveira Falavigna, Tiago Sartor, Amanda Malvessi Cattani, Carla Andrea Delatorre, Sérgio Amorim de Alencar, Orzenil Bonfim da Silva-Junior, Roberto Coiti Togawa, Marcos Mota do Carmo Costa, Georgios Joannis Pappas Jr., Priscila Grynberg, Paulo Ricardo Dias de Oliveira, Marcus Vinícius Kvitschal, Frederico Denardi, Vanessa Buffon and Luís Fernando Revers.
Cross-referencing the results allowed the elaboration of the budding model hypothesis published in a scientific article entitled Spring is coming: genetic analyzes of the budding date locus reveal genes for cold perception and overcoming dormancy in apple trees (Malus X domesticates Borkh.) (Spring Is Coming: Genetic Analyzes of the Bud Break Date Locus Reveal Candidate Genes From the Cold Perception Pathway to Dormancy Release in Apple (Malus X domestica Borkh.)”, published in the magazine Frontiers in Plant Science.
The Embrapa scientist says that the generation of cultivars adapted to scenarios with less cold availability demands advances in the basic knowledge of the biological mechanisms for controlling bud dormancy. “Although we know about the action of some factors on dormancy control, there is still no knowledge of how they interrelate and what can be classified as a cause or consequence”, points out researcher Marcus Vinícius Kvistchal, who coordinates the apple tree genetic improvement program of the Agricultural Research and Rural Extension Company of Santa Catarina (Epagri), partner in Embrapa Grape and Wine research. Kvistchal's team will test in practice the use of knowledge generated in the work to improve apple trees.
The Epagri researcher comments that, if the hypothesis is confirmed, the discovery of the functioning of the ICE1could accelerate the development process of a new cultivar by up to ten years. “The discovery will enable more precise and rapid improvement actions through selection assisted by molecular markers”, he predicts. The scientist explains that from now on, the selection of a new cultivar with lower cold requirements can be done as soon as the seed germinates, eliminating the need to evaluate its development in the field.
Evelyne Costes, researcher in the area of Genetic Improvement and Adaptation of Mediterranean and Tropical Plants (AGAP) at Institut National de la Recherche Agronomiqhuh (INRA), from France, considers the partnership between Embrapa and INRA important to face the challenge posed by climate change. “The complementary expertise of each group is expected to greatly benefit the partnership, implemented since 2016 through a joint project called Dormap, which benefited from funding from Embrapa and Agropolis”, he recalls.
She says that the work is organized into three main scientific axes: the generation and exchange of genomic data; the functional analysis of genes related to dormancy and the exploration of genetic variability to support plant breeding. Among the future results, Evelyne highlights the elaboration of an agreement allowing the creation of the “Associated International Laboratory”, to be built through a partnership between the institutions, in order to facilitate mutual visits by personnel (students and researchers) and the elaboration of new projects to be funded to support research.
More than 600 hours of coldThe apple tree, like other fruit trees in temperate climates, is induced into a state of dormancy by the first cold temperatures of autumn and spends the winter accumulating hours of cold to overcome dormancy and resume growth in spring. Cultivars from the Gala and Fuji groups represent more than 90% of Brazilian production and require an average of 600 to 800 hours of cold to overcome dormancy and achieve sustainable production. According to surveys by the Agrometeorology Area of Embrapa Uva e Vinho, based on data from the Meteorological Stations of the National Institute of Meteorology (inmet), in the last five years, the average cold hours (below 7,2ºC) in the region of Bento Gonçalves (RS) was 302 hours and in Campos de Cima da Serra, 561 hours, that is, below what is considered ideal for good production. To compensate for suboptimal cold exposure, sustainable apple production in southern Brazil depends on the application of chemical agents capable of inducing sprouting. According to monitoring by the technical team, it is common for production losses to occur due to insufficient cold accumulation during the winter rest period and with the prospects of climate change, productivity may be affected. According to the Brazilian Association of Apple Producers (ABPM), today, in addition to serving the national market, Brazilian production is responsible for the annual export of around US$52 million in fresh fruit. Therefore, since 2007, the Embrapa team, in partnerships with universities and research institutes in Brazil and abroad, has been concentrating efforts on the subject, through the execution of several research projects (see table at the end of the text). |
The apple tree, like other fruit trees in temperate climates, is induced into a state of dormancy by the first cold temperatures of autumn and spends the winter accumulating hours of cold to overcome dormancy and resume growth in spring. Cultivars from the Gala and Fuji groups represent more than 90% of Brazilian production and require an average of 600 to 800 hours of cold to overcome dormancy and achieve sustainable production. According to surveys by the Agrometeorology Area of Embrapa Uva e Vinho, based on data from the Meteorological Stations of the National Institute of Meteorology (inmet), in the last five years, the average cold hours (below 7,2ºC) in the region of Bento Gonçalves (RS) was 302 hours and in Campos de Cima da Serra, 561 hours, that is, below what is considered ideal for good production. To compensate for suboptimal cold exposure, sustainable apple production in southern Brazil depends on the application of chemical agents capable of inducing sprouting.
According to monitoring by the technical team, it is common for production losses to occur due to insufficient cold accumulation during the winter rest period and with the prospects of climate change, productivity may be affected.
According to the Brazilian Association of Apple Producers (ABPM), today, in addition to serving the national market, Brazilian production is responsible for the annual export of around US$52 million in fresh fruit. Therefore, since 2007, the Embrapa team, in partnerships with universities and research institutes in Brazil and abroad, has been concentrating efforts on the subject, through the execution of several research projects (see table at the end of the text).
“The choice of research populations was made based on the work carried out by Epagri breeder, now retired, Frederico Denardi. He had already selected some hybrid populations that had less cold requirements within the study that he had been conducting since 1972, at Epagri”, explains Kivtchal, who continued the work.
For this research, two populations were selected based on the average cold requirement phenotype of the parents. In one of the stages of genetic mapping, partial sequencing of the genome of the parents was carried out to find polymorphisms, that is, to identify differences. “It is only possible to create a genetic map if the segregating characteristics are identified and this is the first step”, explains Revers.
The next step was to create the genetic map based on DNA chips for large-scale genotyping (nine thousand single polymorphism markers). In addition to the genotyping work in the laboratory, the team also carried out phenotyping, that is, they evaluated in the field how these populations behaved in relation to cold and sprouting. This activity was under the responsibility of Embrapa researcher Ana Beatriz Costa Czermainski, who over the course of seven years monitored the crossing populations in the field.
The two populations were cultivated respectively in Bento Gonçalves, in Serra Gaúcha, and in Vacaria, in Campos de Cima da Serra, a region with harsher winters, with the aim of measuring the effect of each region's climate on the budding period. “During the experiment, all plants were evaluated two to three times a week, from July to November, to monitor the exact moment of budding and flowering”, says the researcher, who then carried out the analysis that resulted in the phenotyping.
According to Revers, after using a series of complex programs that helped to create the genetic map and exploring phenotyping to identify the loci (DNA regions) associated with budding/flowering, scholarship holder Tiago Sartor carried out a detailed visual inspection of the DNA from the end of chromosome 9 and identified the gene ICE1 in the most significant portion of the locus associated with sprouting.
He says that throughout this work, several articles were published on advances related to the mechanism of dormancy and sprouting in apple trees and the Embrapa group was the only one to identify this gene and its relationship with the process. “Finding the gene ICE1 It was crucial to develop the hypothesis of how dormancy and sprouting occur after the winter period. Now we need to continue and test our hypothesis in practice”, reveals the researcher, who will count on the collaboration of INRA and Epagri in this new stage.
Kvistchal explains that if the hypothesis is proven, the genetic improvement work will be faster, providing an interesting advantage. “Instead of having to wait for the new apple tree selection to present its characteristics in the field, we will be able to carry out the test as soon as the seed germinates and, through DNA extraction, evaluate the gene ICE1. If it has the brand, the selection continues in the evaluation and if it doesn't, it will be discarded”, he explains.
The researcher considers that the discovery will be extremely important for all breeding programs in the world, especially for those interested in developing new cultivars more adapted to regions with less cold, as is the case in Brazil, ensuring greater agility and precision in breeding. of cultivars. In the 47 years of existence of the Epagri Apple Genetic Improvement Program, 19 cultivars were launched, 15 of which were hybrids and four selections of spontaneous mutations.
For Costes, from INRA, the discovery contributed significantly to the study of the dormancy process and genetic control in apple trees. She considers that the team led by Revers confirmed the robustness of the association between the budding date and the locus at the end of chromosome 9, where genes such as ICE1, FLC and PRE1. “The discoveries and the sprouting hypothesis reported in the article open new perspectives for the scientific community and for applications in fruit growing”, she assesses.
Costes highlights that the discovery will not only help the productive sector in southern Brazil, as many other places suffer from reduced exposure to the cold, such as producing regions in the Mediterranean Sea, for example.
“Some of the genes that were associated with the budding date can potentially be used in breeding programs to obtain new varieties better adapted to current and future climate scenarios, in Brazil, but also in different countries and for different climatic conditions”, says the researcher .
Research with apple treesOver the course of 12 years, researchers from Embrapa, Epagri and the Federal University of Rio Grande do Sul (UFRGS) have been carrying out a series of experiments, collections and observations on dormancy control mechanisms in the areas of molecular genetics, genetic improvement, modeling and plant physiology. The main concern was the effects imposed by climate change on the planet, which negatively affected Brazilian pomiculture. These are some publications of these works: Dormancy Database: the Apple Bud Dormancy Database (Apple BDDB) is a web application that allows you to consult a database of genes related to the dormancy process. It presents sample records for the 57 thousand apple genes from eight comparative experiments, resulting in more than 450 thousand expression level records.
Art: Luciana Prado Coordination: Embrapa Grape and Wine. Partner institutions: Embrapa Wheat, Embrapa Genetic Resources and Biotechnology, Embrapa Agricultural Informatics, Agricultural Research and Rural Extension Company of Santa Catarina (Epagri), Federal University of Rio Grande do Sul (UFRGS), Innovation and Research Financier (Finep), Brazilian Association of Apple Producers (ABPM), National Council for Scientific and Technological Development (CNPq), Coordination for the Improvement of Higher Education Personnel (Capes) and Research Support Foundation of the State of Rio Grande do Sul (Fapergs). The project resources come from Embrapa, Epagri, Finep, Capes, CNPq and Fapergs. |
Over the course of 12 years, researchers from Embrapa, Epagri and the Federal University of Rio Grande do Sul (UFRGS) have been carrying out a series of experiments, collections and observations on dormancy control mechanisms in the areas of molecular genetics, genetic improvement, modeling and plant physiology. The main concern was the effects imposed by climate change on the planet, which negatively affected Brazilian pomiculture. These are some publications of these works:
Dormancy Database: the Apple Bud Dormancy Database (Apple BDDB) is a web application that allows you to consult a database of genes related to the dormancy process. It presents sample records for the 57 thousand apple genes from eight comparative experiments, resulting in more than 450 thousand expression level records.
Art: Luciana Prado
Coordination: Embrapa Grape and Wine. Partner institutions: Embrapa Wheat, Embrapa Genetic Resources and Biotechnology, Embrapa Agricultural Informatics, Agricultural Research and Rural Extension Company of Santa Catarina (Epagri), Federal University of Rio Grande do Sul (UFRGS), Innovation and Research Financier (Finep), Brazilian Association of Apple Producers (ABPM), National Council for Scientific and Technological Development (CNPq), Coordination for the Improvement of Higher Education Personnel (Capes) and Research Support Foundation of the State of Rio Grande do Sul (Fapergs). The project resources come from Embrapa, Epagri, Finep, Capes, CNPq and Fapergs.
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