Plant parasitic nematodes are the primary biotic factors limiting soybean and wheat production. In effort to find an alternative method of control, I evaluated the use of producing transgenic soybean and wheat plants expressing siRNAs against specific soybean cyst nematode (SCN) or root lesion nematode genes. More than 25 separate genes related to nematode reproduction or fitness were selected and gene fragments were PCR-amplified using specific primers. RNAi constructs of these genes were transformed into soybean and wheat plants and evaluated by PCR, RT-PCR, Southern blot, siRNA Northern blot and small RNA sequencing. Bioassays performed on transgenic plants expressing dsRNA of SCN genes resulted in up to 85% reduction for eggs g-1 root, which is approaching conventional resistance. Furthermore, I demonstrated a significant reduction in transcript levels of SCN genes of the nematodes feeding on the transgenic roots via real time RT-PCR whereas the expression of non-target genes were not affected. The results of my study demonstrate that over-expression of RNA interference constructs of nematode reproduction or fitness related genes can effectively control SCN and plant parasitic nematode infection.
