Scientists Discover The Likely Reason Behind Durian’s Foul Smell

Why does durian smell the way it does, yet still manage to taste so good? For years, this contradiction of foul smell and sweet taste had been a mystery no one could quite figure out. But a new paper from a team of Singaporean scientists has revealed the probable reason why the so-called “king of fruits” emits such a pungent odor.

As detailed in a report from CNN, a team of researchers from the National Cancer Centre Singapore (NCCS) mapped the genome of the Musang King durian variety, analyzing about 46,000 genes in the fruit and tracing its origins 65 million years ago to the cacao plant, which is the same plant used in chocolate. More importantly, the researchers compared gene activity in multiple parts of the durian, and discovered a series of genes called methionine gamma lyases (MGLs). These genes are responsible for the volatile sulfur compounds (VSCs) produced within the durian, thus giving the fruit its trademark smell.

According to Gizmodo, the durian fruit’s cells also produced an unusually high amount of another enzyme called aminocyclopropane-carboxylic acid synthase (ACS). The durian is believed to have four copies of the MGL gene, as opposed to only one for the cacao plant, and with MGL working in concert with ACS, these two enzymes are likely the ones that cause the foul odor.

“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,” explained co-lead author Patrick Tan, a professor at the Duke-NUS Medical School.

The NCCS’ official press statement also suggests a further reason behind the smell. While humans are oftentimes turned off by the odor emitted by durian, the fruits’ ability to produce high levels of VSC is believed to be essential in attracting animals to consume it, as well as spreading durian seeds to different areas.

The research was mainly carried out in an effort to determine the reason why durian smells the way it does, but the press statement added that the DNA sequencing techniques applied by the researchers could also be used on other types of plants, including plants that could have some medicinal potential. According to NCCS director Soo Khee Chee, such possibilities are exciting due to the “long and distinguished history” of plants yielding some unexpected medicinal value, such as breast cancer drug Taxol being derived from the Pacific yew’s bark.

While durian is a popular fruit in many parts of Southeast Asia, CNN explained that its distinctively foul smell has led Singaporean officials to ban people from eating durian in the subway. With the NCCS researchers having released their new findings, there also might be some hope for an “odorless, subway-friendly” variety of durian to come around in the future.

For the meantime, the researchers are hoping that more research on the durian will be conducted, now that they’ve donated the fruit’s genome data to the Singapore National Parks Board. Gizmodo added that the team is specifically planning a study that could “establish a direct causal link” between ACS and MGL, and further prove that those two agents are responsible for durian smelling like it does.

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