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Genetics

Selected coffee

The manipulation of the genes that control sugars could improve Brazilian coffee

eduardo cesarThe times of glory and absolute reign of the coffee economy have long since passed, but the aroma that spreads out when the boiling water hits the brown powder remains irresistible. Last year Brazilians consumed around 15 million sacks of coffee – they were only overtaken by the Americans with 20 million sacks. A survey, carried out by the Brazilian Coffee Industry Association (Abic in the Portuguese acronym) during 2005, confirmed the appreciation for the drink: 93% of 1,400 people interviewed in eight state capitals consume coffee. Of these, 90% drink at least four small cups every day. In the morning the preference is for filtered, made at home. After lunch, the most wanted is the espresso at coffee shops and bakery stores. More and more a drink of quality is being demanded: 58% of those interviewed drink coffee for the pure pleasure and 47% for the taste that remains in their mouths. When they go to the supermarket, the majority (89%) choose their coffee depending upon the quality of the product, of its flavor (84%) and of the type of coffee (79%). Price comes in seventh place, cited by 70% of those interviewed. If it were to depend on scientific research for improving coffee, like the recently concluded Coffee Genome Project, the consumers can keep cool: the main concern is to guarantee a product of good quality – incorporating flavor and an agreeable aroma.

“Science is in harmony with this demand”, says Paulo Mazzafera, a researcher with the Biology Institute of the State University of Campinas (Unicamp). “The genome results will be used to help in the improvement of production and quality of the coffee.” Luiz Gonzaga Esteves Vieira, a researcher at the Agronomy Institute of Parana (Iapar), reinforced the idea: “The moment is excellent: there are various genes being analyzed. When we define how each of them expresses itself, we can select and reproduce the positive characteristics of the plant and inhibit the undesirable ones”.

Begun in 2002, the Coffee Genome Project received an investment of R$ 6 million – funded by FAPESP, by the Genetics and Biotechnology Resources Unit of Embrapa (Cenargen) and by the Brazilian Consortium of Coffee Research and Development, which brought together 700 researchers and 40 institutions. Around 30,000 genes were identified, which are responsible for determining the different characteristics of coffee. The researchers worked with two species: the Arabic (Coffea arabica), associated with a flavorful drink, grown in the most elevated regions of the country and which represents 70% of national production, and the conilon or Robusta (Coffea canephora), responsible for a coffee that is less flavorful but of stronger body, planted in low altitude areas. “We chose to analyze the genes of organs and different tissue such as leaves, roots, branches and fruit. Starting from this diversity, we selected the most adequate genes”, explains Carlos Colombo, a researcher with the Agronomy Institute of Campinas (IAC). “We came out ahead, and we have a data bank that’s genuinely national. But the competition is great and the information needs to be rapidly used in new studies”, alerts Vieira.

Without losing time, the six institutions that make up the consortium have begun the Functional Genome Coffee Project (Genocafé), coordinated by Mirian Eira, from Embrapa, and financed by the Ministry of Science and Technology, with an initial investment of R$ 3 million. Using data from the genome, the teams from Unicamp, Iapar and the International Cooperation Center of Agronomy Development at Recherche, France (Cirad) have identified two genes that control the level of sucrose in coffee fruit, described in an article that will shortly be published in the Journal of Experimental Botany. It is the quantity of this sugar in the toasted product that determines, in part, the quality of the drink.

At Unicamp, Mazzafera and his doctorate student, Geraldo Aclécio de Melo, have made another discovery associated with coffee quality: they have identified genes that define arrangements established between isomers – molecules with the same formula but different spatial arrangements of their atoms – of chlorogenic acid, partly responsible for the definition of the drink’s flavor and aroma. Mazzafera also organized a special edition of the Brazilian Journal of Plant Physiology, published in March of this year, with 19 revision articles about recent findings concerning coffee – the articles’ coverage ran from cytology and molecular biology of the plant to the quality of the drink. One of them, written by a team from the Federal University of Rio de Janeiro, analyzes the relationship between the proportion of isomers of the chlorogenic acids and the bitterness of the coffee.

According to Vieira, from Iapar, the study is integrated and the research lines of the teams complement each other. At the IAC, the researchers are attempting to describe the genes related to the quality of the drink and to the plant’s resistance to nematoids – microscopic worms that attack the roots of the coffee tree, compromising its development. They are also dedicating their efforts towards an analysis of possible flowering regulator genes, jointly with the team from the Federal University of Lavras. As the coffee plant flowers various times during a year and the collection is done during a single opportunity in order to lower production costs, generally green, mature and dry fruit is gathered in together, a mixture that damages the drink’s quality.

The idea is to select genes that will permit a reduction in there number or duration of flowerings and to concentrate the harvesting at a particular time. Researchers at the Federal University of Viçosa (UFV), in conjunction with a group from Embrapa Coffee Unit, are searching for the genes associated with the control of rustiness – caused by the fungus Hemileia vastatrix, which leaves stains that appear like dust on the leaves, which dry up – and the coffee-leaf miner (Leucoptera coffeella), a lizard that attacks the leaves, knocking them off.

In parallel to the Functional Genome, Clóvis Oliveira Silva and Marcos Buckeridge, from USP’s Biosciences Institute, have identified the gene associated with the alpha-galactosidase enzyme, which controls the quantity of galactose sugar in one of the coffee fibers (mannans) – the level of this sugar affects the solubility of the coffee fibers, important for the quantity and quality of the coffee powder produced. The young seeds contain lots of galactose, which is broken down by the alpha-galactosidase during the maturing of the bean. Consequently: the bean becomes hard and generates a powder that is difficult to dissolve. “If we manage to inhibit the alpha-galactosidase, probably we’ll manage to alter the body of the drink”, explains Buckeridge.

eduardo cesarStandard Colombian: mature fruit give rise to a more tasty drinkeduardo cesar

But the drink’s quality is not associated only to genetics. Silva and Buckeridge have compared the composition of the fruit sugars of the Arabic and Robustaspecies harvested according to the Brazilian standard, which mixes green, mature and dry fruit. They verified that the quantity of mannans, a complex sugar that forms long fibers, was greater in the Arabic species. On repeating the comparison – this time following the Colombian harvesting model that selects only mature fruit -, they noted that the concentration of mannans was practically the same in the two species. “The taste and the aroma of Arabic will always be better because other factors, as well as fibers, influence these characteristics”, admits Buckeridge. “But, by controlling the maturity of the fruit, the taste and the aroma of the Robusta species could improve.”

The researchers know that the Brazilian is discovering the pleasures of a fine coffee and that it is no longer possible – nor desirable – to close one’s eyes to the new standard of consumption. “A cup of coffee must be appreciated in the same manner as we delight about a glass of wine”, says Buckeridge.
To improve the quality of national coffee still represents the possibility of occupying space on the international market. This is a great opportunity for a country such as Brazil, the largest producer and exporter of coffee in the world. According to estimates from the Ministry of Agriculture, the country should harvest in the 2006/2007 crop around 40 million coffee sacks, each of 60 kilograms – an increase of 23% in relation to the period 2005/2006 -, produced in the states of Minas Gerais, Espírito Santo, São Paulo, Paraná and Bahia. Data from the International Coffee Organization show that in 2005/2006 Brazil exported 20.5 millions of coffee sacks, more than Vietnam (11.4 million), and Colombia (10.3 million) and Indonesia (4.6 million).

International quality
One cannot ignore the influence of the coffee production activity on the national economy. According to Embrapa Coffee, there are 2.7 hectares of coffee trees in the country, a crop that generates employment for 8 million people. “Brazilian coffee has been valued at international fairs because of the care taken with its quality”, affirmed Luiz Carlos Fazuoli, a researcher with the IAC. “We compete under conditions of equality with Colombian coffee, considered to be the best in the world”, completes the specialist, a follower of Alcides Carvalho, a pioneer in studies concerning the genetic improvement of the plant.

For Fazuoli, the conclusion of the genome project will also benefit research into the classical genetic improvement of coffee growing. With data from the genome, researcher will be able to identify in the coffee plant’s chromosomes genetic markers associated with the manifestation of certain of the plant’s properties. The next step is to make use of these markers to select plants of agricultural interest, for example, those adapted to a dry climate or capable of generating fruit of a better quality.

But one needs to have patience to see the results. The coffee tree only begins to produce after a year and a half and reaches maturity after ten years. “The objective is to use a selection assisted by markers in order to bring together attributes of agronomy interest in a single species”, suggests Colombo. The genetic improvement of the coffee tree began in Brazil in the decade of the 1930s with Alcides Carvalho, at the IAC. At that time the institute, founded in 1887 by a royal decree from the Emperor Don Pedro II, was already the major national reference point in studies concerning coffee. It is calculated that 90% of the 6 billion coffee trees today spread throughout Brazil are descendants of those grown at the IAC, responsible for developing more than 60 varieties of the Arabic species – among the main ones stand out the novo mundo stand out (which generates a drink of excellent quality), the acaiá (with a faster speed of maturing) and the icatu (sensitive to a dry climate).

Three centuries of history
“With the information from the genome, we’ll go on to work no longer with strips of chromosome, but with specific genes”, explains Mirian Perez Maluf, a researcher with both the IAC and Embrapa Coffee. “The markers will be found in a quicker and more precise manner, lowering the time of experiments and minimizing the probability of error.”

The dialogue between the scientific researchers and quality coffee tree producers initiated a special chapter in a history that began almost three centuries ago, when the Portuguese official Francisco de Mello Palheta brought from French Guiana to Belém, in  the state of Pará, the first coffee seedlings. Before long the drink became a popular taste: by the end of the 18th century, the plant, which originated in Ethiopia, had already arrived in Rio de Janeiro, from where it would spread to the Paraiba Valley, taking in all of the state of São Paulo. “For the Atlantic Rainforest, the introduction of this exotic plant signified a more intense threat than whatever event in the previous 300 years”, wrote Warren Dean, in the book entitled, A ferro e fogo – A história da devastação da Mata Atlântica brasileira [The iron and the fire – the history of the devastation of the Atlantic Rainforest], referring to the large landed estates that substituted the forest.

From the end of the 19th century until the middle of the 20th century, coffee was the main commodity responsible for national development. Its production attracted immigrants. Its commercialization allowed for the construction of railways and promoted industrialization – especially in the Southeast Region. But the so-called black gold, which helped to transform the provincial town of São Paulo into the richest city in the country, left more than an economic legend: it consolidated the traditional “cafezinho” as the mark of Brazilian culture.

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