General Regulatory Factor7 regulates plant innate immune signaling to enhance Verticillium wilt resistance.

Sessile growing plants are always vulnerable to microbial pathogen attacks throughout their lives. To fend off pathogen invasion, plants have evolved a sophisticated innate immune system that consists of cell surface receptors and intracellular receptors. Somatic embryogenesis receptor kinases (SERKs) belong to a small group of LRR-RLK that function as co-receptors regulating diverse physiological processes. GENRAL REGULATORY FACTOR (GRF) proteins play an important role in physiological signaling transduction. However, the function of GRF proteins in plant innate immune signaling remains elusive. Here, we identified a GRF gene, GauGRF7, with constitutive expression and responding to fungal pathogen infection. Intriguingly, Silencing of GRF7 compromised plant innate immunity, resulting in susceptible to Verticillium dahliae (Vd) infection. Both transgenic GauGRF7 cotton and transgenic GauGRF7 Arabidopsis lines enhanced the innate immune response to Vd infection, leading to high expression of two hNLR genes (ADR1 and NRG1) and pathogenesis-related genes, and the increment of ROS production and salicylic acid level. Moreover, GauGRF7 interacted with GhSERK1, which positively regulated GRF7-mediated innate immune response in cotton and Arabidopsis. Our findings revealed the molecular mechanism of GRF protein in plant immune singling and offer potential opportunities for improve plant resistance to Vd infection.