Heat shock-mediated transformation is possible in several Gram-negative bacteria

Area of Science:

• Molecular Biology
• Microbiology
• Genetics

Background:

• Heat shock transformation is a common method for introducing foreign DNA into Escherichia coli.
• Its application in other Gram-negative bacteria is less explored, limiting genetic manipulation techniques.

Purpose of the Study:

• To demonstrate the efficacy of heat shock transformation for gene introduction in diverse Gram-negative bacteria.
• To establish a convenient and widely applicable transformation protocol for non-E. coli strains.

Main Methods:

• Utilized heat shock transformation with CaCl2 treatment to introduce a green fluorescent protein (GFP) plasmid (pDSK-GFPuv) into Ralstonia pseudosolanacearum, Pseudomonas aeruginosa, Pseudomonas putida, and Enterobacter roggenkampii.
• Optimized heat shock conditions (50°C for 60s for R. pseudosolanacearum; 50°C for 180s for others).
• Confirmed successful transformation by observing GFP fluorescence in bacterial colonies and colonization in tomato seedlings.

Main Results:

• Successfully transformed R. pseudosolanacearum, P. aeruginosa, P. putida, and E. roggenkampii using heat shock.
• Demonstrated plasmid stability in R. pseudosolanacearum through re-isolation.
• Visualized successful gene transfer and bacterial colonization in host plants.

Conclusions:

• Heat shock transformation is a viable and efficient method for genetic manipulation of various Gram-negative bacteria beyond E. coli.
• This protocol broadens the applicability of transformation techniques for research and biotechnology in diverse bacterial species.