RNA Interference: An Alternative Approach For Soybean Cyst Nematode Resistance In Soybean

The soybean cyst nematode (SCN), Heterodera glycines, is the most severe biotic stress limiting soybean production, accounting for $4 billion loss per year worldwide. Current SCN management approaches include the use of resistant varieties, crop rotation, and nematicides, all having limitations. We are investigating an in planta transgenic approach for suppressing SCN populations by transferring RNA interference (RNAi) constructs containing inverted repeats of 25 different Heterodera glycines genes into soybean plants, separately. Transgenic roots were evaluated by PCR, RT-PCR, Southern blot, siRNA Northern blot and small RNA sequencing. H. glycines bioassay results performed on the composite plants indicated that 7 out of 25 RNAi constructs resulted in significant reduction for H. glycines eggs, while the other 18 RNAi constructs did not have significant effects. Composite plants expressing RNAi construct of Y-025 and R-001 gene showed consistent suppression of H. glycines HG type 2.7 and HG type 7 populations. Stacking two genes together in one construct did not lead to more significant reduction for H. glycines development. Our research results indicated that RNAi strategy may provide effective and durable SCN control.