The genome of coffee has been sequenced, revealing how one of the world's favourite drinks evolved and providing insights into the beverage's flavour and aroma, an international team of researchers said Thursday.
The findings, published in the US journal Science, may also help scientists improve coffee breeding, accelerate the development of new coffee varieties, and increase the resistance of coffee plants to environmental stresses like climate change and pests.
"The coffee genome helps us understand what's exciting about coffee -- other than that it wakes me up in the morning," Victor Albert, professor of biological sciences at the University at Buffalo, said in a statement.
The team sequenced the genome of Coffea canephora, commonly known as Robusta coffee, which accounts for about 30 percent of the world's coffee production.
Coffea canephora is one of the two most important species of coffee commercially, along with Coffee arabica, which accounts for most of the rest of world coffee production due to its less acidic taste, a result of lower caffeine levels.
Compared to several other plant species including the grape and tomato, coffee harbours larger families of genes that relate to the production of alkaloid and flavonoid compounds, which contribute to qualities such as coffee aroma and the bitterness of beans.
Coffee also has an expanded collection of N-methyltransferases, enzymes that are involved in making caffeine, the study showed.
Upon taking a closer look, the researchers found that coffee's caffeine enzymes are more closely related to other genes within the coffee plant than to those in tea and chocolate.
The researchers said this suggests that caffeine production developed independently in coffee.
If this trait had been inherited from a common ancestor, the enzymes would have been more similar between species, they added.
In an accompanying article, Dani Zamir of the Hebrew University of Jerusalem highlighted the importance of translating the coffee genome into new tools for coffee breeding, particularly as the diversity of coffee plants globally declines.
Zamir urged scientists to share data on traits like aroma and flavour to ensure variation among coffee plant species persists, which will in turn help to mitigate the effects of unstable climate and plant diseases on this crop.
"The danger to the coffee crop should provide an incentive for all stakeholders to initiate international collaborations in genomic-assisted breeding projects and germ plasm conservation with poor, coffee-exporting countries," Zamir wrote.
Scientists from other organizations, particularly the French Institute of Research for Development and the French National Sequencing Center, also contributed to the study, along with researchers from public and private organizations in the United States, France, Italy, Canada, Germany, China, Spain, Indonesia, Brazil, Australia and India.
With more than 2.25 billion cups consumed daily worldwide, coffee is the principal agricultural product of many tropical countries.
According to estimates by the International Coffee Organization, more than 8.7 million tons of coffee were produced in 2013, revenue from exports amounted to 15.4 billion US dollars in 2009- 2010, and the sector employed nearly 26 million people in over 50 countries during 2010. WASHINGTON, September 4 (Xinhua)