Transgenic soybeans expressing siRNAs specific to a major sperm protein gene suppress Heterodera glycines reproduction

The soybean cyst nematode (SCN), Heterodera glycines , is the major disease-causing agent limiting soybean production in the USA. The current management strategy to reduce yield loss by SCN involves the deployment of resistant soybean cultivars and rotation to non-host crops. Although this management scheme has shown some success, continued yearly yield loss estimates demonstrate the limitations of these techniques. As a result, new control strategies are needed to complement the existing methods. Reported here is a novel method of SCN control that utilises RNA interference (RNAi). Transgenic soybeans were generated following transformation with an RNAi expression vector containing inverted repeats of a cDNA clone of the major sperm protein (MSP) gene from H. glycines . The accumulation of MSP-specific short interfering RNA (siRNA) molecules were detected by northern blot analysis of transgenic soybeans. T 0 plants displaying MSP siRNA accumulation were deployed in a bioassay to evaluate the effects of MSP interfering molecules on H. glycines reproduction. Bioassay data has shown up to a 68% reduction in eggs g –1 root tissue, demonstrating that MSPi transgenic plants significantly reduced the reproductive potential of H. glycines . An additional bioassay evaluating progeny nematodes for maintenance of reproductive suppression indicated that progeny were also impaired in their ability to successfully reproduce, as demonstrated by a 75% reduction in eggs g –1 root tissue. The results of this study demonstrate the efficacy of an RNAi-based strategy for control of the soybean cyst nematode. In addition, these results may have important implications for the control of other plant parasitic nematodes.