Identification and functional characterization of the C2H2 ZFP transcription factor CmSUP7 in regulating melon plant growth and fruit development.

The SUPERMAN (SUP) proteins, which belong to the single C2H2 zinc finger proteins (ZFP) subclass, participate in various aspects of gene regulation in plant morphogenesis and stress response, but their role in melon (Cucumis melo) is still largely unknown. We identified a total of 28 CmSUP genes in the melon genome, all containing QALGGH conserved domain. Collinearity analysis showed that melon had several homologous gene pairs with Arabidopsis and tomato, indicating the gene duplication events during the evolution. Expression analyses in RT-qPCR and transcriptomic data showed that CmSUPs can be divided into vegetative organ-expressed genes and reproductive organ-expressed genes. Through genetic transformation of melons, we found that overexpression of the CmSUP7 gene causes dwarfism, reduced internode length, as well as decreased leaf and fruit size. These findings indicate that the CmSUP7 gene significantly affects the melon plant growth and fruit development. Through yeast two-hybrid and BiFC assays, we found that CmSUP7 and CmMYB14 transcription factors directly interact in the nucleus. This study comprehensively analyzed the melon CmSUP family genes and revealed the function of the CmSUP7 gene in regulating melon development, which laid the foundation for further improvement in melon breeding.