Expression of an Antiviral Gene from Soybean Is Regulated via Intron-Mediated Enhancement (IME).

Most of (resistance) genes encode the protein containing NBS-LRR (nucleotide binding site and leucine-rich repeat) domains. Here, plants were used for transient expression assays at 3-4 weeks of age. We identified a TNL (TIR-NBS-LRR) encoding gene that was resistant to both soybean mosaic virus (SMV) and tobacco mosaic virus (TMV). Truncation analysis indicated the importance of all three canonical domains for GmRUN1-mediated antiviral activity. Promoter-GUS analysis showed that expression is inducible by both salicylic acid (SA) and a transcription factor via the cis-elements as-1 and ERE (ethylene response element), which are present in its promoter region. Interestingly, gDNA (genomic DNA) shows higher viral resistance than its cDNA (complementary DNA), indicating the existence of intron-mediated enhancement (IME) for regulation. We provided evidence that intron2 of increased the mRNA level of native gene , a soybean antiviral gene and also a reporter gene Luciferase, indicating the general transcriptional enhancement of intron2 in different genes. In summary, we identified an antiviral type soybean gene , expression of which was regulated at different layers. The investigation of gene regulatory network would help to explore the mechanism underlying soybean-SMV interactions.