Figure 3.
Screening of Nicotiana benthamiana transgenic lines in the T2 generation for resistance against six distinct Cassava brown streak Uganda virus (CBSUV) and Cassava brown streak virus (CBSV) isolates. (A) Phenotype of a resistant line FL17 derived from the RNAi construct targeting the 894 nts of CBSV‐UG[UG:Nam:04]/CP, showing 100% protection (left) when compared with complete infection in control plants (right) when challenged with CBSV‐[TZ:Zan:07]. (B, C) Different levels of protection obtained in N. benthamiana transgenic lines derived from RNAi constructs targeting full‐length (FL; left), C‐terminal (CT; centre) and N‐terminal (NT; right) parts of CBSV‐UG[UG:Nam:04]/CP in the T2 generation after challenge with six different isolates of CBSUV and CBSV. (B) shows protection for CBSUV isolates (CBSUV‐[UG:Kab:07], CBSUV‐[TZ:Kib:07] and CBSUV‐[KE:Mwa:07]) and (C) shows protection for CBSV isolates (CBSV‐[MZ:Nam:07], CBSV‐[TZ:Zan:07] and CBSV‐[TZ:Nal:07]). Different levels of siRNA expressed by these lines positively correlate (R= 0.86) with their resistance levels, as shown in (D).