AtWRKY30 transcription factor mitigates chromium and salt toxicity and induces resistance against bacterial leaf blight and stripe rust in wheat.

Abstract

Chromium (Cr) and salt stresses restrict wheat growth and yield globally. Wheat crops are also adversely affected by bacterial leaf blight and stripe rust caused by Pseudomonas syringae pv. syringae (Pss) and Puccinia striiformis f. sp. tritici (Pst), respectively. WRKY transcription factors revealed great potential in elevating crop resistance to environmental factors. This study assessed the roles of Arabidopsis WRKY30 (AtWRKY30) in regulating wheat tolerance to Cr toxicity, salt stress, bacterial leaf blight and stripe rust. Wild-type and AtWRKY30-overexpressing wheat plants were exposed to non-stressful conditions, Cr toxicity (0.5 mM K₂Cr₂O₇), salt stress (150 mM NaCl), and pathogen infections (Pss or Pst). The results indicated that Cr and salt stresses restricted the growth and reduced the level of chlorophyll, gas exchange rates and potassium content in wheat plants. However, under Cr and salt toxicity, AtWRKY30 overexpression in wheat significantly reduced the levels of oxidative stress biomarkers and minerals (Cr, sodium, and chloride), augmented the growth and yield components, and enhanced the levels of chlorophyll, potassium, gas exchange, osmoprotectants, enzymatic antioxidants, redox components, and expression of stress-related genes compared to wild-type plants. AtWRKY30 overexpression also significantly reduced bacterial leaf blight and stripe rust symptoms in wheat plants infected with Pss and Pst, respectively. Overall, this research demonstrated the effective roles of AtWRKY30 in enhancing wheat tolerance to Cr toxicity, salinity, bacterial leaf blight and stripe rust, indicating its general effect on stress tolerance and redox regulation. Hence, AtWRKY30 can be employed as a promising candidate gene to further boost crop stress tolerance.