Plant Reactome deploys the same Application Programming Interface as the human Reactome Project. Documentation for this API is available here:
Replace the “reactome.org” domain name in the Reactome documentation URLs with “plantreactome.gramene.org”, and then invoke the RESTful web service methods as instructed.
We also have an AnalysisService API, currently in beta. Feel free to try it out and give us your feedback: