The ABRE-BINDING FACTOR 4-eukaryotic translation initiation factor 2B β module mediates drought-potentiated Turnip mosaic virus susceptibility in Brassica juncea.

Turnip mosaic virus (TuMV), an important member of the Potyvirus genus, exhibits broad host adaptability with increased prevalence under moderate drought and elevated temperature conditions. While our previous research identified eukaryotic translation initiation factor 2Bβ (eIF2Bβ) as a critical resistance determinant against TuMV in mustard (Brassica juncea), the mechanistic interplay between environmental factors and viral pathogenesis remains poorly understood. Here, we demonstrated that drought facilitates TuMV infection in an abscisic acid (ABA)-dependent manner in B. juncea. Integrated coexpression analysis revealed the functional relevance between ABA signaling and eukaryotic translation initiation pathways. We showed that ABA-responsive element-binding factor 4 (ABF4) directly binds to the eIF2Bβ promoter and activates its expression and that ABF4 overexpression significantly enhances TuMV accumulation in wild-type plants. Notably, eIF2Bβ knockout lines exhibited significantly reduced viral accumulation even when ABF4 was overexpressed, establishing that functional eIF2Bβ is required to mediate ABF4-dependent viral infection. These findings elucidate a new ABA-eIF2Bβ regulatory module that links drought responses with plant-virus interactions, providing mechanistic insights into the role of environmental factors in modulating pathogen susceptibility.