The coffee genome , the history of caffeine

The sequenzing of the coffee genome (Coffea c.canephora) has highlighted the singular evolution of the capability of the plant in producing caffeine and has cleared some complex reports between numerous different genes. Both of the results will allow an improvement of the organoleptic qualities of the product and the resistance of the plant to diseases.

The research published on “Science” and conducted by an international group of researchers who come from different institutes,between which the Enea centre of Casaccia and the Trieste Universiity-has been concentrated on the specie c.canephora ,from which derives the robust quality of coffee,and not on coffea Arabica,the one tamed in more ancient times and considered more valuable,because the first one is a diploid (it has two copies for each chromosome), while c. Arabica is a tetraploid ( four copies of the chromosomic kit),a circumstance that makes the reading and interpretation of the obtained data more complex.

The first surprised that the sequenzing reserved has been the discovery of the fact that respect to other plants, as for example the tomato or the grapes,coffee has a much higher number of big class genes responsible for the production of alcaloids  and flavonoids .For example,the main fat insatured acid , linoleic acid, that contributes significally to its aroma, is controlled by six genes , against the only gene destined to this task and present in most of the plants that produce it. But the biggest surprise came from the analisis of the biosynthesis patterns of caffeine by c.canephora.The researchers have discovered that caffeine is is produced in a different way respect to other plants that contain this substance,like cocoa and tea.In other words , the ability to synthesize caffeine hasn t been acquired by a common ancestor of coffee,cocoa and tea,but has evolved in different moments and in an independent way.

It is affirmed that caffeine helps the plants keep the parassites away and stops the growth of other plant forms that compete for resources. Another recent study has shown that,like humans,the pollinating insects can become used to caffeine, inducing them to predilect plants that synthesize this composition.  In a comment article of the sequencing ,Dani Zamir of the Hebrew University of Jerusalem at Rehovot, it underlined the importance of translating the sequencing of the genome of coffee in an opportunity for the cultivation of the plant, in a moment in which the diversity of its varieties is becoming diminuishing  at a global level under the pressure of climate changes,deforestation and spread of diseases. In particular, Zamir observes that it would be important to develope  and share a map that links the obtained genetic data and the fenotypical ones, in particular the ones regaurding characteristics such as aroma and flavor.

In this way it would be possible to utilize the rich reserve of genetic diversity still available in the varieties of coffee less utilized which are in Africa, the motherland of the plant,in order to ensure a future at an agricultural sector  that represents the main source of income for  many tropical countries. The actual world production of Arabica coffee,reminds us Zamir, is based in fact on a small number of cultivations with an extremely reducted genomic and fenotypic diversity.