Genome-Wide Identification and Functional Exploration of SBP-Box Gene Family in Black Pepper (Piper nigrum L.)

Black pepper (Piper nigrum L.), is dubbed “the King of Spices”. However, the lack of genic knowledge has limited the understanding of its physiological processes and hindered the development of its molecular breeding. The SBP-box gene family is an important family in plant development and integrates multiple physiological processes. Here, we made a genome-wide identification of the pepper SBP-box gene family to provide evolutionary and functional information about this conserved transcription factor. In total, 34 SBP genes were identified in pepper. All these pepper SBP genes were clustered into eight groups, and one pepper group was not found in Arabidopsis thaliana. Segment duplications played the most important role in the expansion process of pepper SBP genes, and all these duplications were subjected to purifying selection. Half of pepper SBP genes were found miR156 target sites, and 17 miR156s were predicted. The tissue expression analysis revealed the differential expression of pepper SBP genes. Eleven SBP genes were found in four co-expression networks, and the GO enrichment further provides a functional prediction for pepper SBP genes. This study lays a foundation for further studies of pepper and provides a valuable reference for functional mining of pepper SBP genes.