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

Abstract

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. T0 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.