TaHsfA2-11-TaZAT8 module negatively regulates salt tolerance in wheat

Area of Science:

• Plant Molecular Biology
• Abiotic Stress Physiology
• Crop Breeding

Background:

• Plant heat shock transcription factors (Hsfs) are crucial for abiotic stress responses and molecular breeding.
• The wheat Hsf family has complex functions, with individual genes often involved in multiple stress responses.
• TaHsfA2-11, a wheat HsfA2 subfamily member, was previously shown to improve thermotolerance and be upregulated by NaCl.

Purpose of the Study:

• To investigate the function of TaHsfA2-11 in plant salt resistance.
• To elucidate the molecular mechanism by which TaHsfA2-11 regulates salt tolerance.
• To identify potential target genes for enhancing wheat salt tolerance through breeding.

Main Methods:

• Generation of transgenic Arabidopsis thaliana and wheat overexpressing TaHsfA2-11.
• Phenotypic analysis of salt stress tolerance in transgenic and wild-type plants.
• RNA-sequencing (RNA-seq) to identify differentially expressed genes (DEGs) in response to TaHsfA2-11 overexpression.
• Electrophoretic mobility shift assay (EMSA) and dual luciferase reporter assay (DLR) to confirm gene regulation.
• Overexpression of TaZAT8 in Arabidopsis to assess its role in salt tolerance.

Main Results:

• TaHsfA2-11 overexpression in Arabidopsis and wheat led to increased salt sensitivity, with reduced germination and growth.
• RNA-seq revealed DEGs enriched in stress response, ROS, protein folding, and metabolic pathways.
• TaHsfA2-11 directly binds to the promoter of Zinc finger protein 8 (TaZAT8) and activates its transcription.
• Overexpression of TaZAT8 also enhanced salt sensitivity in Arabidopsis, mirroring TaHsfA2-11 phenotypes.

Conclusions:

• TaHsfA2-11 negatively regulates plant salt tolerance, likely by upregulating TaZAT8.
• This regulation involves pathways related to photosynthesis, ROS accumulation, and flavonoid synthesis.
• TaHsfA2-11 and TaZAT8 represent novel targets for genetic engineering to improve wheat salt tolerance.