Fluorescent proteins are increasingly being used as a cellular marker in the study of plant development. We use enhancer trapping, a transactivating system that results in tissue specific fluorescent protein expression, to study development of the apical meristems of Arabidopsis. Tissue initiation and proliferation can be documented via confocal microscopy and then imaging software used to render the data sets 3-dimensionally. This technique of studying living plants is especially powerful when used in conjunction with 3D representations of apicies that have been produced from fixed and cleared samples; very accurate meristem maps have been produced. Enhancer trapping is employed in gene discovery by mapping and sequencing the t-DNA insertion region within the plant genome. Gene expression patterns are thereby visualized and the identity and function of the gene that the enhancer element would normally promote can be discerned. Finally, enhancer trap plants can be secondarily transformed so that any protein of interest can be expressed in the same tissue-specific manner as the fluorescent protein. This opens up many avenues of research including tissue perturbation or ablation by misexpression of normally unexpressed, foreign, or lethal proteins.

Key words: Arabidopsis thaliana, development, enhancer trap, fluorescent protein, GFP, meristem