A minirhizotron imaging system to identify roots expressing the green fluorescent protein

The limited flexibility available in the configuration of commercial minirhizotron imaging systems makes it difficult to adapt these systems to new applications. It is also too expensive to introduce modifications, which are often very temporary to these systems at the end of the development process.In order to identify the roots of a single species in mixed plant stands, we developed a new minirhizotron imaging system that makes it possible to observe roots expressing green fluorescent protein (GFP). This system is based on affordable and easily obtainable components such as webcams. Here, we report a protocol to identify suitable webcams for constructing a minirhizotron imaging system and demonstrate the application of this protocol to build a minirhizotron imaging system that can identify the roots of a transformed maize plant expressing GFP.