# Comprehensive identification and systematical characterization of BRX gene family and the functional of GhBRXL5A in response to salt stress

## TL;DR

This study identifies and characterizes the BRX gene family in cotton, revealing their roles in salt stress response and interactions between specific genes.

## Contribution

The study provides the first comprehensive analysis of the BRX gene family in cotton and identifies GhBRXL5A as a negative regulator of salt stress.

## Key findings

- Silencing GhBRXL5A improved salt tolerance in cotton plants.
- GhBRXL1A and GhBRXL5D showed homotypic and heterotypic interactions.
- Transcriptomic analysis revealed differential regulation of GhBRXL2A/2D and GhBRXL5A/5D under stress.

## Abstract

BRVIS RADIX (BRX) family is a small gene family with the highly conserved plant-specific BRX domains, which plays important roles in plant development and response to abiotic stress. Although BRX protein has been studied in other plants, the biological function of cotton BRX-like (BRXL) gene family is still elusive.

In this study, a total of 36 BRXL genes were identified in four cotton species. Whole genome or segmental duplications played the main role in the expansion of GhBRXL gene family during evolutionary process in cotton. These BRXL genes were clustered into 2 groups, α and β, in which structural and functional conservation within same groups but divergence among different groups were found. Promoter analysis indicated that cis-elements were associated with the phytohormone regulatory networks and the response to abiotic stress. Transcriptomic analysis indicated that GhBRXL2A/2D and GhBRXL5A/5D were up/down-regulated in response to the different stress. Silencing of GhBRXL5A gene via virus-induced gene silencing (VIGS) improved salt tolerance in cotton plants. Furthermore, yeast two hybrid analysis suggested homotypic and heterotypic interactions between GhBRXL1A and GhBRXL5D.

Overall, these results provide useful and valuable information for understanding the evolution of cotton GhBRXL genes and their functions in salt stress.

The online version contains supplementary material available at 10.1186/s12870-024-05220-3.

1. Based on the biological information and systematic analysis of cotton BRX gene family, GhBRXL2A/2D and GhBRXL5A/5D could be used as the candidate genes to validate adversity stress in cotton. Through VIGS verification, GhBRXL5A was a negative regulator of salt stress in cotton.

2. GhBRXL1A and GhBRXL5D have homotypic and heterotypic interactions through yeast two-hybridization assays.

The online version contains supplementary material available at 10.1186/s12870-024-05220-3.