The chapter describes the methods and procedures used in various experiments related to plant development and gene regulation. Immunoprecipitation experiments were conducted to isolate and analyze AP1 and SEP3 proteins, which were mixed with HA-tagged proteins and precipitated using anti-HA antibodies. The precipitated proteins were separated by SDS-PAGE and detected using a radio-imaging analyzer. Transactivation assays were performed in yeast and onion epidermal cells to study the activity of MADS proteins. In yeast, cDNAs of MADS proteins were fused to GAL4 DNA-binding domains and transformed into yeast strains. Yeast cells were grown and β-galactoside activity was measured. In onion epidermal cells, cDNAs of MADS proteins were co-transfected with Clr::GAL4, and LUC assays were conducted using a dual-luciferase reporter system. Plant material from Arabidopsis Columbia ecotype was used for Agrobacterium-mediated transformation and crossing, and the presence of transgenes was confirmed by PCR. Cryo-scanning electron microscopy was used to observe and photograph the samples at −20 °C. The chapter also includes acknowledgments and references to previous studies.The chapter describes the methods and procedures used in various experiments related to plant development and gene regulation. Immunoprecipitation experiments were conducted to isolate and analyze AP1 and SEP3 proteins, which were mixed with HA-tagged proteins and precipitated using anti-HA antibodies. The precipitated proteins were separated by SDS-PAGE and detected using a radio-imaging analyzer. Transactivation assays were performed in yeast and onion epidermal cells to study the activity of MADS proteins. In yeast, cDNAs of MADS proteins were fused to GAL4 DNA-binding domains and transformed into yeast strains. Yeast cells were grown and β-galactoside activity was measured. In onion epidermal cells, cDNAs of MADS proteins were co-transfected with Clr::GAL4, and LUC assays were conducted using a dual-luciferase reporter system. Plant material from Arabidopsis Columbia ecotype was used for Agrobacterium-mediated transformation and crossing, and the presence of transgenes was confirmed by PCR. Cryo-scanning electron microscopy was used to observe and photograph the samples at −20 °C. The chapter also includes acknowledgments and references to previous studies.