Wheat Yellow Mosaic Virus NIb Interacting with Host Light Induced Protein (LIP) Facilitates Its Infection through Perturbing the Abscisic Acid Pathway in Wheat

Positive-sense RNA viruses have a small genome with very limited coding capacity and are highly reliant on host factors to fulfill their infection. However, few host factors have been identified to participate in wheat yellow mosaic virus (WYMV) infection. Here, we demonstrate that wheat (Triticum aestivum) light-induced protein (TaLIP) interacts with the WYMV nuclear inclusion b protein (NIb). A bimolecular fluorescence complementation (BIFC) assay displayed that the subcellular distribution patterns of TaLIP were altered by NIb in Nicotiana benthamiana. Transcription of TaLIP was significantly decreased by WYMV infection and TaLIP-silencing wheat plants displayed more susceptibility to WYMV in comparison with the control plants, suggesting that knockdown of TaLIP impaired host resistance. Moreover, the transcription level of TaLIP was induced by exogenous abscisic acid (ABA) stimuli in wheat, while knockdown of TaLIP significantly repressed the expression of ABA-related genes such as wheat abscisic acid insensitive 5 (TaABI5), abscisic acid insensitive 8 (TaABI8), pyrabatin resistance 1-Llike (TaPYL1), and pyrabatin resistance 3-Llike (TaPYL3). Collectively, our results suggest that the interaction of NIb with TaLIP facilitated the virus infection possibly by disturbing the ABA signaling pathway in wheat.