May 01, 2017 16:17 GMT by dailymail.co.uk

Scientists unravel the genome of the TEA plant

Researchers from the Kunming Institute of Botany in China decoded the tea tree genome to identify the genetic bases of the flavours in tea.

Tea drinkers already have a bewildering selection to choose from when making a brew, but they could soon face a range of enticing new flavours thanks to new research.

Scientists have unravelled the genome of the humble tea plant, which they hope to use to develop varieties with entirely new flavours.

They also hope it may be possible to make tea healthier by boosting certain compounds and breeding varieties that are entirely caffeine free.

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Scientists have unravelled the genome of the humble tea plant, which they hope to use to develop varieties with entirely new flavours

Scientists have unravelled the genome of the humble tea plant, which they hope to use to develop varieties with entirely new flavours

THE TEA TREE 

Most teas are produced from the leaves of the evergreen shrub Camellia sinensis, which was originally native to Asia.

There are another 100 species of plant that are closely related to the tea tree in the Camellia family, but none are suitable for making tea.

The researchers compared the genes and compounds produced by the tea tree to 25 other plants in the Camellia family.

They found while all plants in the family appear to produce many of the same compounds, tea trees appear to have certain genes related to flavour duplicated many times.

This means the tea tree produces high levels of proteins and enzymes involved in creating the bitter compounds known as flavonoids and the caffeine that make tea so drinkable.

Other species did not produce such high levels of these compounds.

This would mean tea lovers would no longer need to turn to chemically treated decaffeinated tea or rooibos, which is made from a South African plant that is not in the tea tree family.

Professor Lizhi Gao, a plant geneticist at the Kunming Institute of Botany in China, who led the work to decode the tea tree genome, said their work had allowed them to identify the genetic basis of the flavours in tea.

It has also allowed them to identify genes that make a particular tea plant suitable for the different types of processing that produce black, green, oolong, yellow and white teas.

This could be used by breeders to cultivate entirely new varieties of tea tree that blend different flavours or even have unique flavours, he said.

Professor Gao said: 'The knowledge of how to genetically form the tea flavours and tea-processing suitability will help breeders to develop different tea tree cultivars with more diversified set of tea favors.

'It is our hope that more new tea tree cultivar varieties would finally satisfy and attract more tea drinkers worldwide.'

Most teas are produced from the leaves of the evergreen shrub Camellia sinensis, which was originally native to Asia.

There are another 100 species of plant that are closely related to the tea tree in the Camellia family, but none are suitable for making tea.

The researchers compared the genes and compounds produced by the tea tree to 25 other plants in the Camellia family.

The researchers hope it may be possible to make tea healthier by boosting certain compounds and breeding varieties that are entirely caffeine free

The researchers hope it may be possible to make tea healthier by boosting certain compounds and breeding varieties that are entirely caffeine free

AN EXPERT'S GUIDE TO THE PERFECT TEA

William Gorman, chairman of the Tea and Infusions Association, claims that boiling water in a kettle more than once can lead to a dull flavoured cuppa.

He suggests that tea drinkers use a good quality loose-leaf or bagged tea - one spoonful or bag per cup.

He says that tea bags should be stored in an air-tight container at room temperature.

And he suggests that when brewing tea in a mug, milk in last is best

They found while all plants in the family appear to produce many of the same compounds, tea trees appear to have certain genes related to flavour duplicated many times.

This means the tea tree produces high levels of proteins and enzymes involved in creating the bitter compounds known as flavonoids and the caffeine that make tea so drinkable.

Other species did not produce such high levels of these compounds.

Professor Gao said different levels of activity in these genes were responsible for changing the way tea can taste when grown in different soils, altitudes and environments.

He said: 'Our results show that differential expression of flavonoid and caffeine-related genes determines the accumulation of secondary metabolic compounds, which further decides tea flavors.

'Levels and patterns of gene expression are dependent upon environmental factors such as altitude and soil minerals.'

While all plants in the family appear to produce many of the same compounds, tea trees appear to have certain genes related to flavour duplicated many times

While all plants in the family appear to produce many of the same compounds, tea trees appear to have certain genes related to flavour duplicated many times

It took nearly five years for the researchers to assemble the whole tea tree genome. At 3.02 billion letters long, it is more than four times the size of the coffee plant genome.

This complexity may also go someway towards explaining the complex mixture of flavours that can be obtained from a single species of plant.

Professor Gao and his colleagues, whose work is published in the journal Molecular Plant, estimated that 67 per cent of the tea tree genome was made of 'jumping genes' that have copied themselves numerous times into various points in the DNA.

William Gorman, chairman of the Tea and Infusions Association, claims that boiling water in a kettle more than once can lead to a dull flavoured cuppa

William Gorman, chairman of the Tea and Infusions Association, claims that boiling water in a kettle more than once can lead to a dull flavoured cuppa

This has led to the plant's genome expanding rapidly, helping it adapt to different climates and environments around the world.

Professor Gao said understanding how the tree is able to cope with stress and disease could also help to reduce the need to use pesticides on tea crops by breeding disease resistant varieties.

He added: 'We are very much interested in doing experiments that knockout the caffeine biosynthetic genes from the tea tree to help breeding of low or non-caffeine tea tree cultivars, which are very still healthy for you but can help you sleep well too.'

 

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