The transcription factors SlWRKY48 and SlWRKY44 antagonistically modulate tomato defense against Meloidogyne incognita

The agricultural pests root-knot nematodes (RKNs) cause economic losses to global crops. However, the underlying molecular basis of plant defense against RKNs is largely unknown. Here, we demonstrated that the tomato transcription factor SlWRKY44 directly bound to the promoter of SlWRKY30IIc (a positive regulator of resistance to the RKN Meloidogyne incognita), thereby up-regulating its expression and activating tomato defense responses against M. incognita. Conversely, SlWRKY48 directly targeted the SlWRKY30IIc promoter to suppress its expression, resulting in reduced resistance to M. incognita. Notably, SlWRKY44 physically interacted with SlWRKY48. They competitively modulated SlWRKY30IIc expression, and antagonistically controlled resistance to M. incognita. Moreover, SlWRKY48 directly regulated SlWRKY44 expression via promoter binding. Collectively, our findings reveal that the balance between the action of the transcriptional activator and repressor on regulation of SlWRKY30IIc determines the outcome of tomato responses to M. incognita.