Genome-Wide Identification and Characterization of TCP Genes in Eight Prunus Species and Their Expression Patterns Under Cold Stress in P. tenella var. tenella.

Background/objectives: Teosinte branched1/Cycloidea/Proliferating cell nuclear antigen factors (TCPs) are plant-specific transcription factors involved in leaf development, flowering, branching, hormone signaling, and stress responses. Prunus a key temperate fruit tree with ornamental spring blooms, still lacks comprehensive TCP gene studies across many species.

Methods: We identified 154 TCP genes in eight Prunus species: 19 in Prunus tenella var. tenella, 19 in P. amygdalus, 17 in P. armeniaca 'Rojo Pasion', 19 in P. mira, 20 in P. jamasakura var. jamasakura, 19 in P. fruticosa, 19 in P. mume var. tortuosa, and 22 in P. × yedoensis 'Somei-yoshino'. These genes were classified into PCF, CIN, and CYC/TB1 groups. We examined segmental duplication, conserved motifs, and cis-acting elements. Expression patterns of 12 TCPs in P. tenella var. tenella were tested under low-temperature stress (25 °C, 5 °C, -5 °C, and -10 °C), and PtTCP9's subcellular localization was determined.

Results: TCP genes within the same groups showed similar motifs and cis-acting elements. Cold stress analysis identified multiple low-temperature-responsive elements in gene promoters. Four genes (PtTCP2, PtTCP6, PtTCP14, and PtTCP16) increased expression under cold stress, while six genes (PtTCP1, PtTCP5, PtTCP8, PtTCP9, PtTCP17, and PtTCP19) decreased. PtTCP9 was localized to the nucleus.

Conclusions: This was the first genome-wide study of the TCP gene family in these eight Prunus species, providing valuable insights into the characteristics and functions of TCP genes within this important genus.