At long last, the mysterious Durian, King of Fruits, has been solved!
Researchers from Singapore, Hong Kong, and Malaysia joined forces to crack open the genome secrets of this amazingly pokey and smelly fruit. If you've never encountered one before, it has a strong flavor and a worse smell, like a sweet sulfuric onion.
Duke-NUS Medical School researchers Bin Tean Teh and Patrick Tan and co-authors mapped the genome the Musang King Durian variety considered the "King of Kings" with delicate texture and strong smell.
They discovered the durian genome has ~46,000 genes or twice as many as humans.
Characterization of the durian (Durio zibethinus) genome:
(a) circos plot of the multidimensional topography of the D. zibethinus genome (right), comprising 30 pseudomolecules that cover ~95% of the assembly; concentric circles, from outermost to innermost, show
(1) gene density,
(2) repeat element density,
(3) GC content, and
(4) syntenic regions with Theobroma cacao (left), the closest sequenced relative in the
Malvaceae family that did not undergo a recent whole-genome duplication event;
(b) distribution of repeat classes in the durian genome;
(c) distribution of predicted genes among different high-level Gene Ontology (GO) biological process terms;
(d) sharing of gene families by durian and three other Malvales plants, with Arabidopsis thaliana as an outgroup; the number in parentheses indicates durian-specific gene families among all 11 plants considered.
Based on all this data, they traced the durian back 65 million years to it's long lost cousin... the cacao plant: Theobroma cacao (chocolate)!
Ever wonder why durians smell so weird? Well, this research team figured it out!
By comparing gene activity patterns from different parts of the durian plant, including leaves, roots, and ripening fruits, they identified a class of genes called methionine gamma lyases that regulate the production of volatile sulfur compounds (VSCs).
“Our analysis revealed that VSC production is turbocharged in durian fruits, which fits with many people’s opinions that durian smell has a ‘sulfury’ aspect,” Professor Tan said.
“In the wild, the ability of durians to produce high VSC levels and a pungent smell may be important in attracting animals to eat and disperse durian seeds to other regions,” the researchers said.
Bin Tean Teh et al. The draft genome of tropical fruit durian (Durio zibethinus). Nature Genetics, published online October 9, 2017; doi: 10.1038/ng.3972