Editing of eIF(iso)4E.c confers resistance against Turnip mosaic virus in Brassica rapa

Abstract

Turnip mosaic virus (TuMV) constitutes one of the primary diseases affecting Brassica rapa, severely impacting its production and resulting in crop failures in various regions worldwide. Recent research has demonstrated the significance of plant translation initiation factors, specifically the eIF4E and eIF4G family genes, as essential recessive disease resistance genes. In our study, we conducted evolutionary and gene expression studies, leading us to identify eIF(iso)4E.c as a potential TuMV-resistant gene. Leveraging CRISPR/Cas9 technology, we obtained mutant Brassica rapa plants with edited eIF(iso)4E.c gene. We confirmed eIF(iso)4E.c confers resistance against TuMV through phenotypic observations and virus content evaluations. Furthermore, we employed ribosome profiling assays on eif(iso)4e.c mutant seedlings to unravel the translation landscape in response to TuMV. Interestingly, we observed a moderate correlation between the fold changes in gene expression at the transcriptional and translational levels (R2 = 0.729). Comparative analysis of ribosome profiling and RNA-seq data revealed that plant-pathogen interaction, and MAPK signaling pathway-plant pathways were involved in eIF(iso)4E.c-mediated TuMV resistance. Further analysis revealed that sequence features, coding sequence length, and normalized minimal free energy, influenced the translational efficiencies of genes. Our study highlights that the loss of eIF(iso)4E.c can result in a highly intricate translational mechanism, acting synergistically with transcription to confer resistance against TuMV.