The modified cassava contains a Cassava brown streak virus-Ugandan cassava brown streak virus RNA interference (RNAi) cassette and and Escherichia coli neomycin phosphotransferase II (nptII) gene cassette.

Transcription of the RNAi commences from a Cassava vein mosaic virus promoter and transcribes: a segment of the Cassava brown streak virus (CBSV) coat protein coding sequence (sense orientation); a segment of the the Ugandan cassava brown streak virus (UCBSV) coat protein coding sequence (sense orientation), a Flaveria trinervia pyruvate orthophosphate dikinase intron 3 (pdk), a CBSV coat protein (anti-sense orientation) and then an UCBSV coat protein segment (anti-sense orientation). Transcription is terminated at an Agrobacterium tumefaciens nopaline synthase terminator. After transcription, the sense and anti-sense sequences within the transcript base pair to form hairpin RNA with the pdk functioning as a flexible sequence to form the loop of the hairpin structure. The double stranded structure of the hpRNA elicits an RNAi response. Dicer-like endonucleases process the hpRNA into small interfering RNA (~21 to 23 nucleotdies in length), which are then recruited by Agronaute proteins to guide the targeted degradation of RNA molecules with sequence homology. In this case, infecting viral transcripts and genome ((+) single stranded RNA) are degraded by the host cell. Due to the processing of the hpRNA, no proteins are expected to be translated from this cassette.

Transcription of the nptII coding sequence is under control of a Cauliflower mosaic virus enhanced 35S promoter and an Agrobacterium tumefaciens nopaline synthase terminator.

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