Chinese cabbage (Brassica rapa L. ssp. pekinensis) is a key staple leaf-heading vegetable widely cultivated in China, while the fungal disease of black spot caused by Alternaria brassicae seriously threats to the growth, development, and quality of Chinese cabbage. Currently, the molecular mechanisms underlying defense responses to black spot disease are largely unknown. In this study, comparative transcriptomic analysis of leaf samples after A. brassicae inoculation in both resistant and susceptible Chinese cabbage lines identified large numbers of candidate regulators of plant–pathogen interactions, and BrERF109 was selected and functionally validated as a key positive regulator in Chinese cabbage defenses against A. brassicae infection. Furthermore, yeast one-hybrid assay and dual luciferase assay confirmed that BrERF109 directly binds to the promoter of BrIGMT4, thereby promoting the accumulation of 4MOI3M of indolic glucosinolates in defending plants against A. brassicae infection. The cover photo showed the BrERF109-BrIGMT4 transcrip-tional regulatory module in Chinese cabbage’s defense against A. brassicae infection, and it was provided by Dr. Qi Zeng and Mr. Xifan Liu from College of Horticulture, Northwest A&F University, China. For more details, please see pages 3895–3908.