# Characterisation of the ARF Gene Family in Salicaceae and Functional Analysis of PeARF18 in Heteromorphic Leaf Development of Populus euphratica

## TL;DR

This study identifies and analyzes ARF genes in Salicaceae plants, focusing on the role of PeARF18 in leaf shape development in Populus euphratica.

## Contribution

The study provides the first comprehensive characterization of ARF genes in Salicaceae and identifies PeARF18's potential role in leaf development.

## Key findings

- 34 ARF genes were identified in each of three Salicaceae species, grouped into six phylogenetic subgroups.
- PeARF18 is significantly up-regulated in ovate/broad-ovate leaves of Populus euphratica.
- ARF gene promoters contain cis-acting elements responsive to light, phytohormones, and stresses.

## Abstract

Auxin plays a crucial role in plant growth and development via concentration gradient regulation, with auxin response factors (ARFs) as key transcription factors in its signalling pathway. However, comprehensive identification and characterisation of ARF genes in Salicaceae remain limited. This study performed a genome-wide analysis of ARF genes in three Salicaceae species (Populus euphratica Oliv., Populus pruinosa, and Salix sinopurpurea), aiming to clarify their physicochemical properties, evolutionary relationships, and functional relevance. A total of 34 ARF genes were identified in each species, all being nucleus-localised hydrophilic unstable proteins clustered into six phylogenetic subgroups. Their promoters contain numerous cis-acting elements responsive to light, phytohormones, and stresses. Transcriptome and qRT-PCR data showed significant up-regulation of PeARF18 in ovate/broad-ovate leaves of P. euphratica compared to linear/lanceolate leaves. This study provides preliminary insights into the characterisation and potential role of the Salicaceae ARF gene family, laying a foundation for further functional exploration of PeARF18 in P. euphratica leaf shape development.