Okay kiddo, let me explain what PGLO is in a simple way.
PGLO is a special kind of bacteria that has been modified by scientists to make it do something amazing - glow in the dark!
The scientists did this by adding a special gene to the bacteria called the GFP gene. This gene makes a protein that glows in bright green color when it's exposed to ultraviolet light.
Now, why did scientists do this? Well, they did it to help them study and learn about how genes work in living things. By using PGLO bacteria, they can easily see how genes can be turned on or off by adding certain chemicals called inducers.
So basically, scientists use PGLO bacteria to study how genes work by making them glow in the dark so they are easy to see and manipulate. It's a really cool way of learning about the world around us!