Scientists Sequence the Coffee Tree Genome

As you drink your morning cup of coffee, you can be confident in knowing that there are teams of scientists in the world working on improving coffee--with the help of genetics. Scientists have identified a reference genome sequence for coffee trees for the first time, which not only improves the understanding of the organization of the genome, but also offers new possibilities for selection or improvement of coffee tree varieties.

While there are many different coffee varieties, the scientists decided to focus on Robusta coffee due to its average sized genome of 710 million pairs of DNA bases. Robust coffee also has a diploid nature, contrary to Coffea arabica, which is tetraploid.

The scientists used several sequencing technologies in order to map the DNA sequence for the coffee tree, assembled in large fragments that were able to be used in various types of analysis. Then, the researchers anchored these sequence fragments to a high-density genetic card to reconstruct the pseudo-chromosomes.

The researchers eventually created a reference genome sequence for coffee trees, and more generally for the Rubiaceae, which is one of the largest families of flowering plants that contains nearly 12,500 species.

What's more interesting is that the researchers found that the organization of the coffee tree genome is best preserved in the Asteridae, which is the family to which potatoes and tomatoes belong, and is very close to that of the ancestral species from which all true Dicotyledons descended through evolution. The findings also improve knowledge of the secondary metabolism of plants and its diversification; the biosynthesis of caffeine, for example, is due to enzymes unique to each species.

Most importantly, though, is the fact that this knowledge could open up new possibilities to improve coffee trees. These trees could be created to be more resistant to environmental factors, or disease. This, in turn, could result in a higher coffee production-which is good news for coffee-drinkers everywhere.

The findings are published in the journal Science.