The GID1-SLR1 interaction is specific for gibberellin in rice protoplasts. (A) Rice protoplasts were transformed with a pair of vectors expressing NRLuc-GID1 or CRLuc-SLR1 in a 96-well plate. Luminescence signals were measured about every 6 min for 120 min before and after adding gibberellin 3 (GA3), gibberellin 4 (GA4), abscisic acid (ABA), indoleacetic acid (IAA), kinetin (KT), salicylic acid (SA), and jasmonic acid (JA) at 10 μM and W5 buffer (as a negative control) in different wells. The plant hormones and W5 buffer were added at 60 min after adding the luciferase substrate (indicated with an open triangle). The graph shows the mean RLU ± S.E. (n = 6). (B) Proteins were extracted from the transformed protoplasts. The proteins were analyzed by immunoblot assays using the anti-NRLuc antibody (left panel) or anti-CRLuc antibody (right panel). Equal protein loading was confirmed by CBB staining. Notice the amounts of recombinant proteins do not change by the plant hormones in this condition.