First, to test whether the development of necrosis during CBSV_Tanza infections of N. benthamiana is specifically associated with the ITPase motifs within the CBSV Ham1 sequence, the CBSV_mutHam IC was constructed whereby the positively charged SH(+)R(+)motif was mutated to neutrally charged serine‐alanine‐alanine (SAA). This evidence concerns the gene ITPA and infection.