Identification of Salt Tolerance-Related NAC Genes in Wheat Roots Based on RNA-Seq and Association Analysis

Area of Science:

• Plant Genetics and Molecular Biology
• Agricultural Science
• Stress Physiology

Background:

• Salinized soils limit wheat production globally.
• The NAC gene family is crucial for plant stress responses, including salt tolerance.
• Identifying and utilizing salt tolerance genes is key to improving wheat in saline environments.

Purpose of the Study:

• To identify and characterize NAC gene family members in common wheat.
• To investigate the role of NAC genes in wheat's response to salt stress.
• To discover novel genes and molecular markers for enhancing wheat salt tolerance.

Main Methods:

• Isolation and classification of 446 NAC sequences from the wheat genome.
• Transcriptome analysis of wheat roots under salt stress (NaCl treatment).
• SNP association analysis with salt-injury rates and root phenotypes in 114 wheat germplasms.
• RT-qPCR validation and mutant analysis of candidate NAC genes.
• Development of a Kompetitive Allele-Specific PCR (KASP) marker for a specific SNP.

Main Results:

• 118 NAC genes (TaNAC1-TaNAC118) were identified, with 144 showing differential expression under salt stress.
• Group 4 NAC genes, including TaNAC26-D3.2, TaNAC33-B, and TaNAC40-B, were upregulated by salt treatment.
• Twenty SNPs associated with salt tolerance were identified, and TaNAC26-D3.2 showed a significant role in salt stress response.
• A KASP marker (K3) was developed for a synonymous SNP in TaNAC26-D3.2, differentiating haplotypes with varying salt tolerance.

Conclusions:

• The NAC gene family, particularly TaNAC26-D3.2, plays a significant role in wheat salt tolerance.
• The K3 marker offers a valuable tool for marker-assisted breeding to improve salt tolerance in wheat.
• This study provides novel genetic resources for developing wheat varieties suitable for saline soils.