# Comprehensive Investigation of GRF Transcription Factors and Associated Responses to Drought Stress in Oat (Avena sativa)

## TL;DR

This study identifies and analyzes GRF genes in oat plants, revealing their roles in drought stress responses and evolutionary patterns.

## Contribution

The first comprehensive characterization of the GRF gene family in oat, including drought-related expression and evolutionary insights.

## Key findings

- 28 GRF genes were identified in oat, grouped into two main phylogenetic clusters.
- Segmental duplication drove GRF gene expansion, with strong purifying selection observed.
- Six GRF genes showed significant up-regulation under drought stress, with AsGRF3 being the most highly expressed.

## Abstract

Growth-regulating factors (GRFs) are plant-specific transcription factors that play important roles in plant growth and development. However, no systematic analysis of GRF genes has been reported in oat (Avena sativa). In this study, we conducted a comprehensive characterization of the GRF gene family in oat, including their physicochemical properties, chromosomal distribution, phylogenetic relationships, gene structure, conserved domains, promoter cis-elements, duplication events, and drought-responsive expression. In total, 28 GRF genes were identified in oat. Phylogenetic analysis classified them into two main groups, which could be further subdivided into five subgroups. Gene structure and conserved motif analyses revealed that AsGRF genes are largely group-specific and relatively highly conserved within each subgroup. Segmental duplication has been the primary driver of AsGRF gene family expansion, and these genes have undergone strong purifying selection during evolution. Transcriptomic analysis identified 13 AsGRF genes expressed under drought stress. Subsequent qRT-PCR analysis revealed that six of these genes were significantly up-regulated. Notably, AsGRF3 showed the highest expression level, was localized to the nucleus, and lacked transcriptional self-activation activity. In conclusion, this study provides a comprehensive analysis of the AsGRF gene family and serves as a valuable reference for further functional characterization of these genes in drought stress responses in oat.