Infrared laser-induced gene expression in single cells characterized by quantitative imaging in Physcomitrium patens

Area of Science:

• Plant Biology
• Molecular Biology
• Biotechnology

Background:

• Precise control of gene expression at the single-cell level is crucial for understanding gene function in space and time.
• The heat shock response is a conserved cellular mechanism that can be leveraged for gene induction.

Purpose of the Study:

• To develop and optimize an infrared laser-evoked gene operator (IR-LEGO) system for spatiotemporal gene expression control in *Physcomitrium patens*.
• To investigate the relationship between laser irradiation parameters (power, duration) and heat shock response induction efficiency and invasiveness.
• To characterize the temporal dynamics of heat shock-induced gene expression.

Main Methods:

• Utilized an IR-LEGO system to induce gene expression in single *Physcomitrium patens* cells via localized heating with an IR laser.
• Systematically varied laser power and irradiation duration to identify optimal conditions for gene induction.
• Employed a heat-induced fluorescence reporter system to quantitatively analyze the heat shock response profile post-laser irradiation.

Main Results:

• Identified optimal IR laser irradiation conditions balancing high inducibility with low cellular invasiveness.
• Demonstrated that longer laser irradiation duration enhances inducibility, while higher laser power, even without apparent damage, can decelerate or delay gene induction.
• Quantified the temporal shift in gene expression (onset and duration) as a function of laser power and irradiation duration.

Conclusions:

• The IR-LEGO system offers a versatile tool for precise, single-cell level gene expression control in plants.
• This study enhances the understanding of heat shock-induced gene expression dynamics in response to localized thermal stimuli.
• Optimized IR-LEGO parameters provide a foundation for advanced spatiotemporal gene function studies in plants.