The coffee genome reveals the evolutionary story behind our favourite pick-me-up

Science 2014-09-16

Along with millions of others around the world you can find a good supply of coffee in the Notch office. Coffee starts the day for millions of people and it can be found in almost every workplace, kitchen and commuter train around the world, which isn’t surprising seeing as we drink over 2.25 billion cups every day. In the UK each year we consume 1.7 kg of coffee per person, compared to 3.1 kg in the USA and a huge 9.6 kg in Finland! As well as being one of the most popular and valuable commodities in the world coffee is also a vast $173 billion industry.

 

However, new research published earlier this month by the University of Buffalo shows that not only is coffee special economically, but it turns out that it’s genetic background is pretty special too!

Coffee Genome

 

This month the University of Buffalo published the first ever genome sequence of the coffee plant Coffea canephora, commonly known as Robusta coffee. The first study of the genome of coffee has revealed some interesting insights into the evolutionary history of the species and in particular the story behind the production of caffeine.

 

What makes the evolutionary history of coffee so interesting is the evolution of caffeine production. The coffee genome encodes a large group of caffeine producing enzymes, N-methyl transferases, which appear to be unique to the coffee plant with no relationship to other caffeine producing plants. Both tea and cacao (chocolate) produce caffeine, however the differences in the genomes show that caffeine production in coffee evolved completely independently. The separate evolutionary paths also explain why the method of caffeine evolution appears to be entirely different.  As opposed to other caffeine-producing plants where there was a huge genome-wide duplication event, in coffee there was a series of small duplications and differentiations that eventually led to caffeine production.

 

So, if two independent evolutionary paths have both led to caffeine production then the question we must ask is: how and why?

 

There appear to be many advantages to plants producing caffeine that vary depending on where the caffeine is produced. When caffeine is produced in the leaves it is a strong insecticide and defence mechanism that repels insects from eating the foliage. Caffeine produced in the seeds and fruit could be used to stunt the growth of neighbouring competitors to set a growth advantage. Finally there is new evidencethat suggests pollinating insects can develop a caffeine habit much like humans, insects are more likely to revisit a plant if it produced caffeine.

 

So why is it important for us to know more about the genetics of coffee?

 

Firstly knowing more about the genome of coffee could lead to a better tasting coffee. The sequencing of the coffee genome has revealed the location of alkanoid and flavonoid genes that are responsible for the characteristic aroma and bitterness of coffee. However a better tasting cup is not the only benefit.

 

Importantly, we may be able to develop strains of coffee that are more resistant to disease and climate change and make it a more reliable crop. Over 125 million people depend on the coffee industry for their livelihood and 90% of the production is in the developing world. By developing more stable strains that can withstand drought and disease we could give security of income to those that rely most on the coffee industry.

 

So whether you’re a coffee hater or a caffeine-addict, coffee is an incredibly special and important plant to both biology and the economy.

 

Let me know what you think @GabyAtNotch. Are you a fellow coffee lover

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