A tale of survival: Molecular defense mechanisms of soybean to overcome Soybean mosaic virus infection

Plant viruses represent some of the greatest contributors to crop losses worldwide. Viral disease symptoms often include mosaic leaf patterns, crinkled and yellowed leaves, plant stunting and even necrosis. As intracellular pathogens, viruses hijack host cell machinery for their own replication, which can elicit dramatic changes to their hosts at the cellular, molecular and physiological levels. Soybean mosaic virus (SMV) is a widely distributed soybean pathogen, which can cause severe stunting and yield losses to infected plants. A better understanding of the underlying interactions between SMV and soybean will aid in the establishment of disease management plans. In these studies, we implemented high throughput RNA sequencing approaches and targeted metabolite profiling to describe transcriptomic and metabolic changes occurring in soybean leaves ten days post-infection with SMV. A massive defense response was detected by the increased accumulation of transcripts associated with biotic stresses, including those involved in pathogen recognition, autophagy and defense inductors. Moreover, significant decreases in expression were detected for transcripts associated with fundamental growth and development processes, such as nutrient transport and photosynthesis. At the metabolomic level, significant changes were identified in correspondence with viral infection, particularly in amino acid concentrations. Overall, it appears as though SMV inoculated plants reroute their limited resources as a survival strategy, favoring defense over plant development.