The accurate identification of exons and introns that comprise a complete plant gene structure can be a time-consuming and challenging task. Novel Web-based tools facilitate the process by providing a convenient interface to current transcript evidence, and portals to relevant bioinformatics software. With a few keystrokes, the user can explore alternative transcript assemblies and, for example, select for annotation those that are clearly supported by transcript evidence and similarity to known genes. The implementation of the tool at the PlantGDB resource also allows immediate communication of the novel annotations to the community through Web display.