Molecular cloning and characterization of GhWRKY11, a gene implicated in pathogen responses from cotton

WRKY transcription factors are key regulators in signaling networks that modulate many plant defense processes. Although the functions of WRKY proteins have been well studied in model plants, their roles in cotton pathogen defense mechanism are still unknown. In the present study, we cloned a cotton group IId WRKY transcription factor gene, designated as GhWRKY11, which has only one copy in cotton genome and was targeted to the nucleus. Promoter sequence analysis revealed various cis-acting elements related to plant defense responses. Furthermore, semi-quantitative RT-PCR analysis indicated that GhWRKY11 was induced by pathogen (Colletotrichum gossypii) attack, wounding treatment and certain defense-related molecules, including salicylic acid (SA), methyl jasmonate (MeJA), ethylene (ET) and hydrogen peroxide (H2O2). In addition, overexpression of GhWRKY11 in Nicotiana benthamiana resulted in an elevated resistance potential to cucumber mosaic virus (CMV) compared to the wild-type, following the enhanced transcript levels of SA associated genes (PR1 and NPR1) and reduced H2O2 accumulation. These results suggest that GhWRKY11 may play important roles in regulating plant defense responses through SA- and reactive oxygen species (ROS)-mediated signal pathways.