Paulo Mazzafera, professor of Unicamp’s Biology Institute, studies creation of a commercially viable caffeine-free coffee variety (P.Mazzafera)

Work of Brazilian researcher is featured in Nature
2012-05-02

Paulo Mazzafera, professor of Unicamp’s Biology Institute, studies creation of a commercially viable caffeine-free coffee variety.

Work of Brazilian researcher is featured in Nature

Paulo Mazzafera, professor of Unicamp’s Biology Institute, studies creation of a commercially viable caffeine-free coffee variety.

2012-05-02

Paulo Mazzafera, professor of Unicamp’s Biology Institute, studies creation of a commercially viable caffeine-free coffee variety (P.Mazzafera)

 

By Karina Toledo

Agência FAPESP – For more than 20 years, researcher Paulo Mazzafera has attempted to create a naturally caffeine-free variety of coffee that can be grown on a commercial scale. The study was featured in Nature magazine on March 15.

Twice before, Mazzafera, full professor at the Vegetal Biology Department at State University of Campinas (Unicamp) Biology Institute, believed that he had reached his objective. The first was in 2004, when in partnership with Maria Bernadete Silvarolla, a researcher at the Campinas Agronomy Institute (IAC), he discovered some plants from Ethiopia that were caffeine-free through natural mutations.

Because the plants were Coffea arabica, considered the most flavorful and of the greatest commercial value, the discovery seemed promising. In an article in Nature published in 2004, the group described that the Ethiopian varieties had an alteration in the final stage of the biochemical process that transforms theobromine – a diuretic substance that is a light stimulant – into caffeine.

“We are ecstatic. We know that the plants found were not very productive, but because it was Coffea arabica, we thought it would not be easy to splice and transmit this characteristic (lack of caffeine) to more productive crops,” explains Mazzafera in an interview with Agência FAPESP.

However, it was not that simple because splicing caused the offspring plants to recover the capacity to synthesize caffeine.

The IAC team has not lost hope and maintains a research line under Silvarolla’s coordination. Mazzafera decided to attempt a new approach: treating Coffea arabica seeds of a commercial variety known as Catuaí Vermelho with substances that can alter the plant’s DNA.

In a study funded by FAPESP from 2006 to 2008, almost 30,000 seeds were exposed to two mutagenic agents – sodium azide and ethyl methane sulphonate - in the hope that the gene responsible for caffeine synthesis would be affected by one of them.

Among the thousands of plants analyzed, five proved to be good candidates, and Mazzafera once again thought he was close to reaching his target. “I was excited because I had obtained a potentially very productive variety like the Catuaí and without caffeine.

However, during the first tests, the researcher noticed that the plant’s mutant flowers opened before they were supposed to, leaving them more susceptible to receive pollen from varieties with a normal caffeine level. “Cross pollination ended up restoring the caffeine levels. In order to avoid this, one would have to isolate the planting in a ray of 2 kilometers, which will be unfeasible,” he explained.

The team sequenced the caffeine synthase gene in the mutant plant and verified that it was normal but had little expression. “We most likely hit a transcription factor, or rather, a gene that controls caffeine synthase expression and also controls some gene related to flowering,” explains Mazzafera.

Transgenic alternative

Three years ago, the team managed to correct the problem through new splicing. Simultaneously, it sought to better understand the transcription factor affected by the mutagenics.

“We have two good candidates. We are going to silence these genes in a normal plant to prove that in fact they control by caffeine synthesis as well as flowering. The second stage would be to make them control only caffeine synthesis,” explains Mazzafera.

Even if they are successful, the researchers would have to overcome the taboo associated with consumption of genetically modified food to transform the research results into a product with commercial value.

Groups from other countries have also tried unsuccessfully to develop a decaffeinated coffee plant through genetic engineering, as noted in the Nature magazine article. Because the decaffeinated market turns over approximately US$2 billion annually, scientists’ quest to find natural decaf has shown no signs of weakening, even after successive setbacks.

“Many people don’t drink coffee because they don’t want to feel the stimulant effects of caffeine, and at the same time, think the taste of artificially decaffeinated coffee is bad,” says Mazzafera.

This taste occurs because the existing processes for extracting caffeine also remove other substances in coffee, such as phenolic and chlorogenic acid. These substances are important to guarantee not only the aroma and taste of the beverage but also its antioxidant effect.

“If we manage to create a variety of coffee that keeps the other characteristics of Coffea arabica, many more people will drink coffee,” opines Mazzafera.

New research

Until this happens, the researcher also dedicates his time to improving the transformation process of sugarcane into biofuel. In a Thematic Project connected to the FAPESP Bioenergy Research Program, Mazzafera studies environmental factors that influence lignin synthesis in the plant.

“One of the factors that have made the transformation of sugarcane bagasse into second-generation ethanol is lignin,” he explains. The substance is responsible for the rigidity, impermeability and resistance of vegetal tissue but also hinders fermentation of cellulose.

“Plants cannot survive without lignin, but perhaps it is possible to modify the substance and reduce its level. The idea is to make bagasse more digestible for microorganisms or make lignin extraction easier through other chemical processes,” said Mazzafera.

In another project recently approved in a joint call for proposals released by FAPESP and Agilent Technologies, Mazzafera and his team will study how the variation in temperature and the high concentrations of carbon dioxide in the atmosphere influence the synthesis of lignin in two species of eucalyptus.

“Eucalyptus globulus, native to cold regions, has a much higher concentration of cellulose than Eucalyptus grandis, the species that exists in Brazil. In some manner, the climate alters the plant’s lignin structure. Our objective is to ensure that globulus manages to adapt to warmer climates, which interests the whole world in the context of global warming,” he said.

 

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