# Cotton STARD Gene Family: Characterization, Evolution, and Expression Profiles During Salt Stress

## TL;DR

This study explores cotton STARD genes and their role in salt stress, identifying key genes like GhSTARD45 that could help improve cotton's salt tolerance.

## Contribution

The study identifies GhSTARD45 as a key gene in root-mediated salt tolerance in cotton.

## Key findings

- STARD genes are evenly distributed across four cotton species.
- Segmental duplication is the main driver of STARD gene expansion.
- 11 GhSTARD genes, including GhSTARD45, show significant expression changes under salt stress.

## Abstract

Background: Cotton, a key global economic crop, suffers yield and quality losses due to salt stress. This study aims to analyze the cotton STARD gene family and its role in salt stress responses. Methods: We conducted a genome-wide analysis of the STARD gene family in four cotton species, using phylogenetic trees, chromosomal mapping, and collinearity analyses to explore their evolutionary relationships and expansion mechanisms. We also examined gene structures, conserved motifs, and promoter cis-elements. Results: STARD genes are evenly distributed across the four cotton species. Segmental duplication was found to be the main driver of gene expansion, with most pairs undergoing purifying selection. Distinct structural features and potential roles in plant growth and stress responses were identified. Notably, 11 GhSTARD genes showed significant expression changes under salt stress, especially GhSTARD45 in root tissues. Conclusions: This study provides new insights into the function and salt stress response mechanisms of the cotton STARD gene family, suggesting GhSTARD45 plays a key role in root-mediated salt tolerance and highlighting the potential of STARD genes in enhancing cotton’s salt tolerance.