3 minute read
New research published today, in PLOS Biology, from teams at the Sainsbury Laboratory Cambridge University (SLCU), UC Davis in the US, and NPL, describes a new tool called “Highlighter”, which uses specific light conditions to trigger targeted gene expression control in plants – humans ‘talking’ to plants.
The team at SLCU has previously engineering a series of high-resolution biosensors for critical plant hormones that use fluorescent light to visually communicate in real-time what is happening in plants at the cellular level and how plants are reacting to environmental stresses – plants ‘talking’ to humans.
Now the team have demonstrated that they can control plant immunity and pigment production by modifying the wavelength spectrum of visible (white) light.
To understand cellular activity, biologists need to control biomolecular process at the cellular level. Scientists can do this using ‘optogenetics’ and targeting a light stimulus to specific cells to activate or deactivate a specific process. However, applying optogenetic tools to plants is challenging as plants need to be exposed to a wide spectrum of light to grow. Switching from dark to light activates native plant photoreceptors and cross-talks with myriad cellular systems.
This challenge was overcome with the support of John Clark Lagarias from UC Davis who suggested re-engineering the light activated CcaS-CcaR protein. This was originally sourced not from plants but from photosynthetic microbes, which use CcaS-CcaR to control gene expression in response to changes in the ratio of green (on) – red (off) light. Therefore, by varying the amount of red and green light in the white light plants need to grow, the engineered CcaS-CcaR (i.e., Highlighter) enables genes to be turned on or off while minimising off-target effects on the plant’s normal physiology.
However, when developing Highlighter, the SLCU team detected an unexpected blue-off behaviour. Working with scientists Alex Jones, Ines Camacho, and Richard Clarke at NPL, spectroscopic studies of Highlighter confirmed that the new system was still able to use green and red light just like the original system. But the NPL data also showed evidence of an independent effect of blue-light. Dr. Alex Jones, Tehcnical Lead of the NPL team said “This represents an intriguing new property of the system, which could translate to greater versatility of the Highlighter tool. We look forward to investigating it in more detail.”
When deployed in plants, Highlighter responds to minimally invasive light signals, is able to be activated and inactivated, and is unaffected by the light-dark cycling in growth chambers. Further work is planned to progress development of Highlighter, but the team has already demonstrated optogenetic control over plant immunity, pigment production and a yellow fluorescent protein, the latter at cellular resolution.
The concept of humans being able to communicate with plants on a meaningful level has long captured the imagination of people. If such a capability was possible, it could revolutionise agriculture and our relationship with plants.
“If we could warn plants of an impending disease outbreak or pest attack, plants could then activate their natural defence mechanisms to prevent widespread damage,” Dr Alexander Jones, SLCU, said. “We could also inform plants about approaching extreme weather events, such as heatwaves or drought, allowing them to adjust their growth patterns or conserve water. This could lead to more efficient and sustainable farming practices and reduce the need for chemicals.”
Read more here.
View the research paper here.
22 Sep 2023