Some plants have developed a remarkable evolutionary strategy to emit the foul odor of rotting meat or dung, which serves to attract flies for pollination.
This putrid smell, typically produced by bacteria decomposing animal carcasses, has long puzzled scientists regarding how plants can generate it themselves.
Recent research published on May 8 in Science reveals that several unrelated plant species independently evolved this stinky trait through similar genetic changes.
Scientists in Japan discovered that these plants duplicated a gene called SBP1 and then mutated the extra copy. These mutations altered the enzyme produced by SBP1, enabling the plants to synthesize the smell of carrion.
In particular, wild ginger (Asarum simile), the East Asian eurya shrub (Eurya japonica), and the Asian skunk cabbage (Symplocarpus renifolius) each achieved this malodorous ability with a small number of amino acid changes in the enzyme.
Normally, the SBP1 enzyme breaks down methanethiol-a smelly compound responsible for bad breath-into less odorous substances. However, the mutated enzyme links methanethiol molecules into dimethyl disulfide, a chemical that smells strongly of rotten meat.
This evolutionary adaptation has appeared multiple times in the Asarum genus alone, with the ability to produce dimethyl disulfide gained and lost over 18 times. The production of this foul scent provides a selective advantage by attracting more flies, which pollinate these plants.
The study highlights how gene duplication and subsequent mutations in plants can lead to novel traits such as the production of carrion-like odors. This mechanism is a vivid example of how plants have evolved complex biochemical pathways to ensure reproductive success by mimicking the smell of decaying organic matter to lure pollinators
