Genome-wide identification and characterization of TCP transcription factors in peanut

Abstract The plant-specific TCP transcription factors (TFs) play important roles in multiple processes of plant development and environmental stress response. However, the characteristics of TCP TFs in peanut are still unclear. In this study, we characterized the peanut TCPs including the numbers, classification, structures, and expression patterns based on the information from the available database. We identified 28, 9, and 8 TCPs in A. hypogaea cv. Tifrunner (AhTCP1-28), A. duranensis (AdTCP1-9), and A. ipaensis (AiTCP1-8), respectively. These genes can be divided into three groups based on the phylogenetic tree: PCF, CIN, and CYC/TB1. A total of 10 paralogous gene pairs in A. hypogaea cv. Tifrunner, five orthologous gene pairs between A. duranensis and A. hypogaea cv. Tifrunner and five orthologous gene pairs between A. ipaensis and A. hypogaea cv. Tifrunner, were identified respectively. Most duplicated gene pairs underwent purifying selection except AdTCP2-AhTCP15 and AiTCP8-AhTCP28 were subjected to positive selection. Hormone-related and abiotic stress response elements were abundant in several TCP gene promoters in A. hypogaea cv. Tifrunner. AhTCP12 and AhTCP25 contained four EREs (ethylene-response elements), and AhTCP15 included four TCA elements. Most of TCPs were expressed lowly in 22 tissues, however, several genes such as AhTCP25 and a homologous gene pair, AhTCP13 and AhTCP28 , were expressed highly in peg tip and perianth, respectively. AhTCP duplicated gene pairs did not show significant functional differentiation. This study provided insight into the evolution and expression of AhTCP s and might assist peanut molecular breeding.