The StABI5-StCAT1 Module Regulates Potato Resistance to Early Blight Through the ROS Signaling Pathway

Area of Science:

• Plant Pathology
• Plant Biochemistry
• Molecular Plant-Microbe Interactions

Background:

• Early blight, caused by *Alternaria solani*, significantly impacts potato yield.
• Catalase (CAT) is an antioxidant enzyme involved in plant immunity, but its role in potato early blight is not well understood.
• Hydrogen peroxide (H₂O₂) accumulation is linked to plant-pathogen interactions.

Purpose of the Study:

• To investigate the role of Catalase (StCAT1) in potato resistance to early blight.
• To elucidate the signaling pathway involving StCAT1 in plant defense.
• To identify genetic resources for developing disease-resistant potato varieties.

Main Methods:

• Utilized a hydrogen peroxide (H₂O₂) biosensor in *Nicotiana benthamiana* to monitor H₂O₂ levels during *A. solani* infection.
• Performed exogenous H₂O₂ application on potato leaves followed by pathogen inoculation.
• Employed gene silencing and overexpression techniques for *StCAT1* and *StABI5* in potato.
• Assessed antioxidant enzyme activities (SOD, PAL, CAT) and disease resistance.

Main Results:

• *A. solani* infection induced sustained H₂O₂ accumulation in tobacco leaves.
• Elevated H₂O₂ levels promoted early blight infection in potato.
• *StCAT1* expression was upregulated by *A. solani*.
• Silencing *StCAT1* reduced antioxidant activity and disease resistance, increasing H₂O₂.
• Overexpressing *StCAT1* enhanced resistance and decreased H₂O₂ levels.
• StABI5 was identified as an upstream transcription factor activating *StCAT1* expression.
• Silencing *StABI5* compromised potato resistance.

Conclusions:

• StCAT1 positively regulates potato resistance to early blight.
• The StABI5-StCAT1 signaling pathway is crucial for mediating this resistance.
• Findings provide a scientific basis for breeding disease-resistant potatoes.