# Genome-Wide Identification of the TCP Gene Family in Chimonanthus praecox and Functional Analysis of CpTCP2 Regulating Leaf Development and Flowering in Transgenic Arabidopsis

## TL;DR

This study identifies and analyzes TCP genes in wintersweet, focusing on CpTCP2's role in leaf development and flowering in Arabidopsis.

## Contribution

The study provides the first genome-wide analysis of TCP genes in Chimonanthus praecox and functionally characterizes CpTCP2 in transgenic Arabidopsis.

## Key findings

- 22 CpTCP genes were identified in Chimonanthus praecox, all containing a conserved TCP domain.
- CpTCP2 overexpression in Arabidopsis led to reduced leaf area, delayed flowering, and increased rosette leaf numbers.
- MeJA treatment accelerated leaf senescence in CpTCP2 transgenic Arabidopsis.

## Abstract

TCP transcription factors represent a crucial family of plant regulators that contribute significantly to growth and developmental processes. Although the TCP gene family has been extensively studied in various plant species, research on Chimonanthus praecox (wintersweet) remains limited. Here, we performed genome-wide identification and analysis of the TCP gene family in C. praecox and identified 22 CpTCP genes. We further systematically examined the associated physicochemical properties, evolutionary relationships, gene structures, and regulatory features. Analysis revealed that all CpTCP proteins possess a conserved TCP domain, and subcellular localization prediction indicated their localization in the nucleus. Promoter analysis revealed that multiple cis-elements are associated with abiotic stress responses and plant growth regulation. Further analysis revealed high CpTCP2 expression in the leaves and stamen, with significantly increased levels during flower senescence. CpTCP2 expression was upregulated in response to methyl jasmonate (MeJA), salicylic acid, abscisic acid, and shade. CpTCP2 overexpression in Arabidopsis thaliana resulted in a reduced leaf area, delayed flowering, and increased rosette leaf numbers. Moreover, MeJA treatment accelerated leaf senescence in CpTCP2 transgenic Arabidopsis. These findings provide insights into the evolutionary characteristics of the TCP family in C. praecox, highlighting the functional role of CpTCP2 in regulating leaf development and flowering time in Arabidopsis, thereby offering valuable genetic resources for wintersweet molecular breeding.