The news feed being full of messages on the tea genome sequencing in Yunnan, we’d also like to make a small commentary on the study.
To begin with, scientists in different countries have been working with the tea tree genes for many years, and their researches often have a rather applied character. For example in Nanjing they have figured out what genes are responsible for the content of Ascorbic acid and L-theanine in tea and are planning to use this information for developing new tea cultivars. In case of the full genome sequencing the answer to the question “now that we have it decoded, what’s next” is not that straightforward obvious. And the suggested variant of the answer “now we know why tea is so popular” doesn’t fit either — we knew, without the genome being sequenced, that we appreciate tea for its flavor and the pleasant physiological effect.
This, however, doesn’t mean that, in Yunnan, scientists have worked hard only to tell us the obvious, only with genetic pictures. The fact is that during the study they were able to identify specific groups of genes that are responsible for those characteristics of the tea tree, which the group of scientists considered most attractive to consumers. These are: the content of caffeine, catechins and theanine.
Here we need to make a remark. The matter is that in Yunnan, they have studied one tea tree cultivar — Yunkang 10 (C. sinensis var. assamica). Genetic codes of different varieties of one plant may be very different. For example, the genome size of Coffee arabica is almost 1.5 times bigger than that one of Coffee robusta. And the sequencing of every new variety from scratch is a time-consuming and expensive task (the study of Yunkan-10 took more than five years). And now, knowing which genes are responsible for the consumer-relevant characteristics of tea, specialists will be able to carry out targeted decoding of genomes of other varieties faster and cheaper. Very roughly speaking, now they know what to look for.
For example, Yunnan experts are very much interested in the idea of studying genetic mechanisms that predetermine the consumer appeal of old wild tea trees. We consider this idea attractive too, of course.
Well and as it happens, such a large-scale research couldn’t do without interesting and amusing observations. In particular, Yunnan specialists found out that the genes responsible for the content of theanine are common to all Camellia species that they studied. And high expression of genes responsible for the content of catechins and caffeine is present only in Thea species of Camellia genus. And, casually, scientists have demonstrated that tea is genetically not at all like potatoes and peppers, and is closer to kiwi fruit than to coffee.
