CRISPR Unlocks the Secrets of Flowering in Plants

For generations, humans have admired the beauty of flowers. But beyond their visual appeal, flowers play a crucial role in plant reproduction. This process is guided by a well-studied gene known as Unusual Floral Organs (UFO). The expression of UFO depends on a complex mechanism called cis-regulation, which has long been a "black box" in plant biology research.

Using CRISPR gene editing, Cold Spring Harbor Laboratory (CSHL) Professor and HHMI Investigator Zachary Lippman and his colleagues are exploring how non-coding DNA segments, known as cis-regulatory regions, influence the timing, location, and level of UFO expression. Lippman believes these insights could one day help researchers make more informed decisions about genetic modifications to enhance crop traits.

"We could have chosen many other genes, but this one stood out because of its exquisite regulatory control. The flower is a complex structure, and the genes governing its development are tightly regulated in time, space, and expression levels."

 Zachary Lippman, Professor, Cold Spring Harbor Laboratory

The research focused on two distantly related flowering plants: tomato and Arabidopsis. The team identified DNA sequences that, while not coding for proteins, are present in the regulatory regions of UFO in both species.

Lippman emphasized the significance of these sequences, noting their evolutionary conservation.

"It's a strong indication that these sequences have been preserved because they play an essential role in controlling gene expression. But to confirm their function, we needed to introduce mutations and observe the effects."

Using CRISPR, Lippman and his team modified these non-coding sequences to examine their impact on flower formation. Their findings revealed that these sequences significantly influence flowering in both plants. However, the effects of these modifications varied by species. For instance, removing a specific sequence in tomatoes promoted flower production, whereas deleting a similar sequence in Arabidopsis inhibited blooming.

"It’s fascinating that different deletions had opposite effects on flowering. It suggests these sequences work together to maintain the delicate balance necessary for flowers to bloom at the right time and place."

Amy Lanctot, Postdoctoral Researcher, Cold Spring Harbor Laboratory

This discovery advances our understanding of how cis-regulatory regions shape gene function.

"Our goal is to deepen our knowledge of the complexity of cis-regulatory DNA. With this understanding, we can make more precise decisions about which sequences to modify and the types of mutations that could be beneficial."

Zachary Lippman

As researchers continue to unlock the secrets of cis-regulation, their findings could pave the way for more effective genetic modifications in agriculture, ultimately improving crop yield and resilience.