Central Role of Ubiquitination in Wheat Response to CWMV Infection

Ubiquitination is a major post-translational modification (PTM) involved in almost all eukaryotic biological processes and plays an essential role in plant response to pathogen infection. However, to date, large-scale profiling of the changes in the ubiquitome in response to pathogens, especially viruses, in wheat has not been reported. This study aimed to identify the ubiquitinated proteins involved in Chinese wheat mosaic virus (CWMV) infection in wheat using a combination of affinity enrichment and high-resolution liquid chromatography-tandem mass spectroscopy. The potential biological functions of these ubiquitinated proteins were further analyzed using bioinformatics. A total of 2297 lysine ubiquitination sites in 1255 proteins were identified in wheat infected with CWMV, of which 350 lysine ubiquitination sites in 192 proteins were differentially expressed. These ubiquitinated proteins were related to metabolic processes, responses to stress and hormones, plant-pathogen interactions, and ribosome pathways, as assessed via Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses. Furthermore, we found that the ubiquitination of Ta14-3-3 and TaHSP90, which are essential components of the innate immune system, was significantly enhanced during CWMV infection, which suggested that ubiquitination modification plays a vital role in the regulatory network of the host response to CWMV infection. In summary, our study puts forward a novel strategy for further probing the molecular mechanisms of CWMV infection. Our findings will inform future research to find better, innovative, and effective solutions to deal with CWMV infection in wheat, which is the most crucial and widely used cereal grain crop.