Transgenic Soybean Plants with Root-Expressing siRNAs Specific to HgRPS23 Gene are Resistant to Heterodera glycines.

The soybean cyst nematode (SCN, Heterodera glycines) poses a serious threat to soybean production worldwide. RNA interference approach was taken in this study to silence the essential SCN ribosomal protein gene HgRPS23 in the roots of transgenic soybean plants. The treatment of SCN J2 worms with the HgRPS23 dsRNA produced by in vitro transcription has been previously shown to lead to SCN lethality. Our analysis indicated that the conserved HgRPS23 225 bp shares high homology with 5’-terminal sequence of the Caenorhabditis elegans CeRPL1 gene, and that the predicted small interfering RNA (siRNA) species from the HgRPS23 225 bp dsRNA finds its exact match in CePRL1. Our results showed that soaking C. elegans L2 worms in HgRPS23 225 bp dsRNA could result in C. elegans lethality. Transgenic soybean plants (cv. Williams 82) were produced with Agrobacterium-mediated transformation to express the hairpin structure of the HgRPS23 in the roots with the Arabidopsis root-specific pyk10 promoter. The TaqMan probebased RT-qPCR analysis with a uniquely designed key-like RT primer demonstrated that the predicted HgRPS23 siRNA was highly expressed only in the roots of transgenic soybean plants. Our data showed that the HgRPS23 siRNA-expressing transgenic soybean plants were highly resistant to SCN infection.