P-235 - Conservation and functional relevance of the interaction between C4 from geminiviruses and the receptor-like kinase BAM1

Geminiviruses are some of the most devasting plant pathogens worldwide, causing dramatic crop losses. Among the canonical proteins encoded by geminiviruses, C4 is the smallest but most diverse one; whether this diversity also translates to protein functionality remains to be determined. Here, we investigate the functional diversity of C4 proteins encoded by 9 different geminiviruses. C4 from tomato yellow leaf curl virus interacts with the plasma membrane (PM)-localized receptor-like kinase BARELY ANY MERISTEM 1 (BAM1) at the PM and plasmodesmata (PD) and suppresses the cell-to-cell movement of RNA interference (RNAi), considered the main anti-viral defence in plants. We found that all C4 proteins studies here interact with BAM1 at the PM and PD; however, not all suppress the cell-to-cell movement of RNAi. We have mapped the interaction between C4 and BAM1, and identified conserved resides required for the interaction; the functional impact of this protein-protein interaction in the context of the viral infection is currently under investigation.