dCas9

Researchers at the Bose Institute have developed an innovative genetic tool, utilizing a modified version of CRISPR called dCas9, to help plants cope with stress. Unlike traditional CRISPR which cuts DNA, this dCas9 acts as a “switch” that can turn genes on or off without altering the DNA sequence. Crucially, this switch remains off until the plant experiences stress.

How the ‘Smart Switch’ Works:

• The dCas9 Mechanism: Instead of cutting DNA like conventional CRISPR, dCas9 is designed to regulate gene expression. It can either activate (turn on) or suppress (turn off) specific genes.
• Stress-Responsive Activation: The key innovation lies in its stress-dependent activation. The switch remains inactive until the plant is exposed to stress, ensuring targeted gene regulation only when needed.
• Borrowed from Tomato Biology: To achieve this stress-responsive function, scientists incorporated a small piece of a natural protein from the tomato plant called NACMTF3. This specific part, known as the TM domain, acts like a tether, holding the dCas9 switch outside the cell’s nucleus (the “control room”).
• Stress Response: When the plant experiences stress, such as heat, the TM domain “lets go” of its tethering function. This allows the dCas9 switch to enter the nucleus and activate or suppress the target genes, enabling the plant to respond to the stress.

Applications and Future Potential:

• Target Plants: The team successfully tested this system in tomatoes, potatoes, and tobacco, demonstrating its efficiency.
• Stress Resistance: This research, published in the International Journal of Biological Macromolecules, shows promise in helping solanaceous plants (the family that includes tomatoes and potatoes) handle various environmental challenges.
• Combating Pathogens and Heat: The tool proved particularly effective in tomatoes combating the bacterial pathogen Pseudomonas syringae, which becomes more virulent during heat waves. This indicates its potential for developing plants that can better fight diseases and tolerate extreme temperatures.