Emerging multifactorial complexity at the geminivirus-host interface

Viruses manipulate their host cells to replicate and spread.

This manipulation is based on the activity of virus-encoded proteins, limited due to restrictions in genome size imposed by the viral cycle.

How the action of these few proteins results in the massive cell reprogramming observed during the infection remains enigmatic. Geminiviruses are plant viruses causing diseases in crops worldwide.

Recent results obtained in our lab using the geminivirus Tomato yellow leaf curl virus (TYLCV) indicate that the proteome of this species, so far believed to encompass 6 proteins, is far more complex than anticipated: the TYLCV genome contains additional open reading frames expressed during the infection and giving rise to new proteins, and viral transcripts are spliced and generate new protein variants.

Therefore, the number of viral proteins exceeds double that previously accepted.

In addition, we have found that this higher complexity is further increased by the association of viral proteins in an intricate network of intra-viral interactions, which enable novel protein localization and function, leading to an expansion of their interactome and functional spaces.

Our results imply that, to get a complete overview of the molecular and functional landscape of plant-geminivirus interactions, the strategies traditionally used, based on the analysis of a limited number of viral proteins in isolation, need to be revisited.

Here, we propose to apply a combination of genomic, interactomic, and functional approaches to generate a comprehensive map of the virus/host cell intersection with unprecedented resolution.

We will perform a comparative analysis of different geminivirus species, and translate these emerging concepts to independently evolved viral families.

The conceptual and practical enlargement of the virus/host interface elucidated in this project has the potential to re-shape the theoretical framework and experimental approaches in the study of virus/host interactions.