Toronto, Ontario, Canada
January 23, 2026
A close‑up of Alpinia mutica, whose anther and style switch roles each day to prevent self‑pollination. Researchers have now identified the SMPED1 gene that drives this remarkable reproductive timing.Photo credit: All images courtesy of Spencer Barrett.
In 1876, the naturalist Charles Darwin wrote that “Cross-fertilization (in plants) is generally beneficial, and self-fertilization injurious.”
He was pointing out that when an individual plant fertilizes itself, it can lead to harmful inbreeding. In contrast, cross-fertilization with other plants of the same species promotes genetic diversity, adaptability and resilience.
Because of this, flowering plants have evolved many strategies to ensure cross-fertilization. For example, in the flowers of the ginger Alpinia mutica, the male anther and female style — its reproductive organs — “take turns” being active over the course of a single day.
In the morning, a bee gathering nectar from an A. mutica flower collects pollen released from the bloom’s active anther. But it doesn’t immediately deposit any of the pollen on the flower’s own style when it departs, because the style is raised out of the way, like an open turnstile.
Then in the afternoon, the anther and style switch roles. The anther closes and stops releasing pollen, while the style drops into position; as the bee enters, it now brushes the style and deposits the pollen it brought from a different plant — thus achieving cross-fertilization.
Spencer Barrett in the Pantanal region in Brazil in 2015.
“That the plant has these two, synchronous sex phases is incredible.” says University Professor Emeritus Spencer Barrett in the Faculty of Arts & Science’s Department of Ecology & Evolutionary Biology. “Think about it — at around noon every day, the anther and style change positions and sexual phases.”
While this adaptation has been studied before, the genetic underpinnings of it were unknown. Now, Barrett and his collaborators have identified the gene that controls this reproductive behaviour of both male and female organs.
“We’ve identified the gene controlling this daily synchronicity and named it the SMPED1 gene, for Style Movement and Pollen Early Dispersal 1,” says Barrett, an evolutionary plant biologist and a leading authority on the reproductive biology and genetics of flowering plants. Barrett is a co-author on the paper published in the journal Nature Plants describing the finding.
Plants like A. mutica, with male and female reproductive organs that are active at different times, are called dichogamous and come in two forms: in protandrous (PA) plants, the male sex organs are active first; in protogynous (PG) plants, it’s the female sex organs that are active first.
What sets A. mutica apart is that plants are either PA or PG; in other words, at any given time, some plants in a field of ginger are PA while the remainder are PG. This means that when pollinating insects fly from flower to flower, there are both PA flowers from which to pick up pollen and PG flowers to receive it — again, resulting in cross-pollination.
Many flowering plants are either protandrous or protogynous, but because A. mutica is both, it was possible for Barrett and his colleagues to identify SMPED1.
If you could put this gene into a self-pollinating species, it's possible you could induce dichogamy in them that would promote cross pollination. It's possible that this gene could be used by plant breeders to alter the reproductive strategies of certain crops.
“To determine the inheritance of a trait — in our case dichogamy — one needs to have variation; think of the biologist Gregor Mendel’s experiments with tall versus short peas or smooth vs wrinkled seed coats,” says Barrett.
“The problem is that most dichogamous species are either protandrous or protogynous but not both. You generally cannot cross different species which might differ in dichogamy so one is thwarted by the lack of variation within a species for dichogamy. Alpinia resolves this problem because in populations there are both protandrous and protogynous individuals which can be crossed with one another, and thus the trait — dichogamy — can be studied genetically.”
Because the gene is found in other flowering plants, the researchers suggest it likely works in a similar way in them.
“This discovery provides new insights into the mechanisms governing plant reproduction and evolution,” says John Stinchcombe, a distinguished professor of ecological genetics in the Department of Ecology & Evolutionary who was not involved in the study. “And since the timing of sexual function is important in plant breeding, they could be exploited for crop improvement.”
Says Barrett, “If you could put this gene into a self-pollinating species, it's possible you could induce dichogamy in them that would promote cross pollination. It's possible that this gene could be used by plant breeders to alter the reproductive strategies of certain crops.”
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