The interaction network of a rice seed-specific transcription factor OsMADS29 and the calcium sensors, calmodulin, and calmodulin-like proteins.
Calmodulin (CaM) and calmodulin-like (CML) proteins, as calcium sensors, are key modulators of plant signaling and development, yet their roles in regulating seed-specific transcription factors remain underexplored. Here, we investigated the interaction landscape between the rice seed-specific MIKC-type MADS-box transcription factor OsMADS29 and the CaM/CML family. Phylogenetic and expression analyses identified 40 CaM/CML genes expressed during seed development, of which 28 were cloned for interaction studies. Bimolecular fluorescence complementation assays revealed that OsMADS29 interacts with 22 CaM/CML proteins, showing distinct cytoplasmic or dual cytoplasmic-nuclear localization patterns, while yeast two-hybrid assays confirmed 20 of these interactions. Further, four additional MADS-box proteins (OsMADS7, 8, 14, and 15) also demonstrated interactions with CaM and selected CMLs, indicating a broader regulatory network. Our interaction data suggest a potential role of CaM/CML proteins in modulating OsMADS29 subcellular localization, likely influencing its dimerization and regulatory functions during seed development. This study establishes a conceptual framework linking calcium signaling to the regulation of MADS-box transcription factors and provides a foundation for future functional analyses of how CaM/CML interactions influence MADS-mediated transcriptional control during rice seed development.