Study Shows RNAi-derived Resistance to Cassava Brown Streak Disease

Cassava brown streak disease (CBSD) is one of the major threats to food security in tropical Africa. Thus, Emmanuel Ogwok from the National Crops Resources Research Institute and colleagues, developed genetically modified cassava plants to form small interfering RNAs (siRNAs) from Ugandan cassava brown streak virus (UCBSV) coat protein sequence. siRNA-producing lines were examined under confined field trials in Namulonge, Uganda.

Results showed that the transgenic plants exhibited a 3-month delay in disease development compared to the nontransgenic control plants which showed CBSD symptoms on aerial tissues six months after planting. Reverse transcriptase-polymerase chain reaction (RT-PCR) diagnostics confirmed the presence of the virus in the leaves of the 57% of the control plants, while only 0.5% of the transgenic lines had virus in the leaves. Furthermore, the harvested roots from the control plants were severely affected by the virus manifested by necrosis. Roots from transgenic plants showed suppression of the disease, with 95% of the lines free from necrosis.

These findings provides proof of principle for the control of CBSD using RNAi technology.

Read the abstract of the study at http://onlinelibrary.wiley.com/doi/10.1111/j.1364-.3703.2012.00812.x/abstract.