Comparative genomic investigation of TCP gene family in eggplant (Solanum melongena L.) and expression analysis under divergent treatments.

KEY MESSAGE: The putative TCP genes and their responses to abiotic stress in eggplant were comprehensively characterized, and SmTCP genes (Smechr0202855.1 and Smechr0602431.1) may be involved in anthocyanin synthesis. The Teosinte branched1/Cycloidea/Proliferating cell factors (TCPs), a family of plant-specific transcription factors, plays paramount roles in a plethora of developmental and physiological processes. We here systematically characterized putative TCP genes and their response to abiotic stress in eggplant. In total, 30 SmTCP genes were categorized into two subfamilies based on the classical TCP conserved domains. Chromosomal location analysis illustrated the random distribution of putative SmTCP genes along 12 eggplant chromosomes. Cis-acting elements and miRNA target prediction suggested that versatile and complicated regulatory mechanisms that control SmTCPs gene expression, and 3 miRNAs (miR319a, miR319b, and miR319c-3p) might act as major regulators targeting SmTCPs. Tissue expression profiles indicated divergent spatiotemporal expression patterns of SmTCPs. qRT-PCR assays demonstrated different expression profiles of SmTCP under 4 °C, drought and ABA treatment conditions, suggesting the possible participation of SmTCP genes in multiple signaling pathways. Furthermore, RNA-seq data of eggplant anthocyanin synthesis coupled with yeast one-hybrid and dual-luciferase assays suggested the involvement of SmTCP genes (Smechr0202855.1 and Smechr0602431.1) in the mediation of anthocyanin synthesis. Our study will facilitate further investigation on the putative functional characterization of eggplant TCP genes and lay a solid foundation for the in-depth study of the involvement of SmTCP genes in the regulation of anthocyanin synthesis.