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Poster

Session: Session 1 Presenting Authors at Posters (Odds)

P-249 - Loss-of-affinity screening and targeted genome editing converge on an nCBP2 motif critical for CBSV VPg interacting and CBSD disease severity

Monday, July 14, 2025
13:30 - 15:15  
Location: Confex Hall 3
Plant-virus Interactions (incl. Viromes, Evolution & Vectors)

Cassava is a crucial food security crop in sub-Saharan Africa. There, a key constraint on production is cassava brown streak disease (CBSD). CBSD is caused by independent or simultaneous infection with two species of positive sense RNA viruses belonging to the family Potyviridae, genus Ipomovirus: cassava brown streak virus (CBSV) and Ugandan cassava brown steak virus (UCBSV). Diseases caused by the family Potivirdae have been found to require the interaction of viral genome-linked protein (VPg) and host eukaryotic translation initiation factor 4E (eIF4E) family members. Cassava encodes five eIF4E-family members: eIF4E, eIF(iso)4E-1, eIF(iso)4E-2, nCBP-1, and nCBP-2. We previously found that cassava ncbp-1 ncbp-2 double mutants exhibited attenuated CBSD symptoms and reduced storage root viral titer. Full resistance was not achieved, however. Interestingly, CBSV VPg was found to associate with all cassava eIF4E-family members by co-immunoprecipitation. We used targeted and unbiased mutagenesis of nCBP-2 coupled with protein-protein interaction assays to better understand how the CBSV VPg and eIF4E-family protein complex is assembled. We tested the effect of mutating a conserved motif in nCBP-2 on disease caused by CBSV.