London, July 15 (ANI): Researchers have sequenced the genome of bananas, the humble yellow staple food facing pests and diseases that threaten to wipe it out across the globe, in an effort to save them from imminent demise.
The accomplishment opens the way for developing better banana crops that are naturally resilient against parasites and other stresses.
"The banana is very important, especially for tropical and subtropical countries," Angelique D'Hont, a geneticist at CIRAD, an agricultural research center in Montpelier, France, said.
"Because the future of the banana is in danger, the sequence will help to produce resistant bananas and avoid the utilization of pesticides. It will be much easier now to identify genes which are important," D'Hont said.
Bananas were first domesticated 7,000 years ago in Southeast Asia. As people migrated, and crossed their own plants with other species along the way, bananas gradually became seedless, delicious and totally sterile.
Instead of multiplying through sexual reproduction, which mixes up the gene pool, bananas are cultivated through vegetative propagation, which involves simply cutting off a section of one plant to grow on its own.
It's the same process used to grow several other major African crops, including cassava, sweet potatoes and yams.
As a result, every single Cavendish banana - the variety that makes up about half of all bananas eaten around the world - is an exact clone of every other Cavendish banana.
The shape, colour and flavour of these popular fruits are predictable and consistent. But parasites and diseases have adapted to the Cavendish, D'Hont said, making it necessary to use large amounts of pesticides to keep banana crops from collapsing-up to 50 applications a year in some places.
To decipher the banana's genetic strengths and weaknesses, D'Hont and a large group of colleagues spent two years sequencing a variety of banana called Musa acuminate, which is a simpler relative of the Cavendish.
Once they put together the sequence they discovered several genes that may be involved in pest resistance.
Among other findings, the researchers identified genes involved in ripening after the application of ethylene, which is often added to green bananas during transport.
The sequence also revealed that the banana duplicated its entire genome three times - including once 100 million years ago and once 60 million years ago
Putting together the sequence took so long because, compared to many other crops, the banana genome is extremely complex.
Even though all bananas are clones of each other, the original gene forms that came from mother and father plants remain different from each other-unlike in seeded crops that tend to become inbred, said Simon Chan, a plant biologist at the University of California, Davis.
The variety of banana used in the new study had just two of each chromosome, making it simpler than the Cavendish.
But by finally deciphering its sequence, scientists will be able to move on to our beloved breakfast fruit and compare the differences.
The study has been recently published in the journal Nature. (ANI)
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