# Comprehensive Analysis of the TaABCB Gene Family and the Role of TaABCB7 in the Phosphate Starvation Response in Wheat

## TL;DR

This study identifies and analyzes the TaABCB gene family in wheat, focusing on TaABCB7's role in responding to phosphate starvation.

## Contribution

The study identifies 99 TaABCB genes in wheat and highlights TaABCB7 and its elite haplotype H001 for phosphate starvation response.

## Key findings

- 99 TaABCB genes were identified and categorized into four groups in wheat.
- TaABCB7 is potentially involved in regulating wheat's response to phosphate starvation.
- An elite haplotype H001 of TaABCB7 has been used in wheat breeding programs.

## Abstract

The ABCB subfamily is crucial for plant processes like transporting important substances, but its specific role in wheat (Triticum aestivum L.) is not well understood. This study found 99 TaABCB members in wheat, grouped them into four categories, and analyzed their genome-wide features. Transcriptome analysis showed different expression patterns under phosphate starvation stress, with TaABCB7 potentially regulating this stress. An elite haplotype H001 of TaABCB7 was identified and used in wheat breeding. This study deepens our understanding of TaABCB members and provides a gene resource for wheat breeding.

The ABCB subfamily, a subset transporter of the ATP-binding cassette (ABC) superfamily, is vital for various plant life processes, especially in the transport of polar auxin and brassinosteroids. Although ABCB transporters have been characterized in diverse plant species, their specific functions in wheat remain largely unexplored. In this study, we identified 99 TaABCB members in wheat and categorized them into four groups based on their conserved domains and phylogenetic relationships. These members were found to be unevenly distributed across all 21 wheat chromosomes. We conducted a comprehensive genome-wide analysis encompassing gene structure, protein motifs, gene duplication events, collinearity, and cis-acting elements. Transcriptome analysis revealed that different TaABCB members displayed distinct expression patterns under phosphate starvation stress. Notably, we discovered that TaABCB7 might play a role in regulating wheat’s phosphate starvation. Crucially, we pinpointed an elite haplotype, H001, of the candidate gene TaABCB7, which has been progressively selected and employed in wheat breeding improvement programs. Overall, this study enhances our comprehensive understanding of TaABCB members and offers a potential gene resource for molecular marker-assisted selection breeding in wheat.