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Why do some flowers bloom in bold stripes, while others display dots or rings? Biologist Jason Gardiner has now received a €1 million grant to uncover the molecular logic behind petal pigmentation. Together with biologists at the ľ�ϸ���Ӱ�� of Amsterdam and several companies, Gardiner aims to build fundamental knowledge with real-world applications. This may help breeders create more stable flowers, fruits, and vegetables. The grant is awarded by the Dutch Research Council (NWO).

The project will use petunias, chrysanthemums, and orchids as models to uncover how flowers create and maintain their striking colour patterns. Jason Gardiner leads the project together with biologists Francesca Quattrocchio and Ronald Koes from the ľ�ϸ���Ӱ�� of Amsterdam, both experts in flower genetics and pigmentation research.

“The key question is why we get different patterns,” says Gardiner. “We know a lot about the molecular pathway that makes the colours in flowers. We even know where this pathway gets blocked when sections of the petal turn white. But what actually causes the appearance of stripes, rings or dots is still a mystery.”

What's the trigger?

“The genome of a cell that is white and one that is purple is the same” says Gardiner. “So, there must be something else that’s triggering all these colour variations.”

Most likely, the explanation lies in tiny chemical changes that influence which parts of the genome are used in a particular cell, without altering the genetic code itself. Scientists call these epigenetic marks.

Zooming in on individual cells

To solve this, this project will use advanced methods to zoom in on individual cells within a flower and watch what each one is doing at a given moment. This is almost like creating a detailed map of activity inside the petal. This approach is known as spatial single-cell sequencing.

Stable patterns

Gardiner: “You might see a nice pattern in one flower, but it’s different in other flowers of the same plant. By understanding what’s going on, we can help predict when a certain pattern is going to be stable within a plant and across the seasons. And also, what it takes to maintain a desired pattern.”

While the project tackles a fundamental biological puzzle, breeders of flowers and even crops are eager for answers too.

While the research tackles a fundamental biological puzzle, breeders of flowers and even crops are eager for answers too. The project is a collaboration between Utrecht ľ�ϸ���Ӱ��, the ľ�ϸ���Ӱ�� of Amsterdam, and companies from the ornamental, food crop, and biotechnology sectors. The companies involved include orchid breeder Anthura, chrysanthemum specialists Deliflor and Dekker, berry producer Driscoll’s, seed producer Enza Zaden, and Hudson River Biotech. The companies provide 10% of the project’s budget.

“It’s great to have these companies on board,” says Gardiner. “They really help us bring our fundamental research into the applied space so people can benefit from what we find.” 

Flower breeders in the team are interested in applying the findings to make the patterns in varieties more stable. The biotechnology partners are keen to refine advanced techniques like single-cell sequencing and CRISPR. And the food crop breeders see opportunities to translate the knowledge into more stable and resilient fruits and vegetables.

A window into bigger questions

For Gardiner, flowers are more than ornamental beauty. They also provide a gateway to understanding how all living organisms develop, including humans.

By understanding how cells make these choices, we can better understand why patterns form in other instances as well.

“We all start as a single cell that divides into a blob of cells. At some point, even though each cell has the exact same genome, cells decide to become a skin cell or an eye cell. The patterns we see in flowers offer us a way to understand how these types of decisions are made: does a cell start to produce pigment or not? By understanding how cells make these yes or no choices, we can better understand why patterns form in other instances as well.”