Exploring resistance in potatoes to combat blackleg disease

Blackleg, a devastating bacterial disease primarily caused by Pectobacterium carotovorum, poses a considerable threat to potato production. Accordingly, it is critical for the development of resistant cultivars to elucidate the physiological bases of resistance. Here, the resistance of 12 potato cultivars to blackleg were evaluated, identifying two highly resistant cultivars, and three susceptible cultivars. High resistant varieties Zhongshu 170 and Zhongshu 316 exhibited significantly lower decay levels compared to susceptible varieties, including Houma, Hongdao, and Huashu No. 2. This study also investigates the variations in malondialdehyde (MDA), proline (Pro), and hydrogen peroxide (H2O2) content among potato varieties with different blackleg resistance levels. The results indicate that high susceptibility is associated with elevated MDA and Pro, consistent with severe membrane lipid peroxidation. By contrast, H2O2 levels did not align strictly with resistance rankings, suggesting genotype-specific ROS signaling and scavenging strategies. Detection of antioxidant enzyme activities after pathogen inoculation showed that the activities of superoxide dismutase (SOD) and peroxidase (POD) in resistant varieties increased sharply post-inoculation. Additionally, catalase (CAT) and ascorbate peroxidase (APX) activities increased across all varieties after infection, with resistant types showing higher levels. Finally, the correlation analysis revealed a complex relationship between these indicators and disease resistance. Overall, this provides a scientific foundation for breeding programs aimed at developing potatoes with improved resistance to blackleg disease, ultimately enhancing agricultural strategies and production efficiency.