LncRNA-encoded small peptide promotes viral infection

The small open reading fragments (ORF) embedded in lncRNA have been identified to encode biologically functional peptides in many species. However, the function of lncRNA-encoded small peptide in plant antiviral response remains unclear. In this study, we identified a lncRNA Talnc54748 which encode a small peptide ORF4 to negatively regulated plant resistance to Wheat yellow mosaic virus (WYMV) infection. Transgenic overexpressing ORF4 in N. benthamiana was also reduced viral infection. RNA-sequencing analysis revealed that a lot of genes in plant hormone signals and MAPK signals was reduced in ORF4 transgenic overexpression lines. In addition, the function of SAUR21 and MKK2 belong to plant hormone signals and MAPK signals respectively was further investigated by virus-induced gene silencing assay. We found that silencing SAUR21 or MKK2 in wheat and N. benthamiana enhanced WYMV infection. Moreover, the accumulation of TMV and ToMV was also induced in the ORF4 transgenic overexpression lines. Accordingly, our results demonstrated that lncRNA-encoded small peptide play an important role in plant viral infection and provide new insights into the roles of lncRNA-encoded small peptide in plant antiviral response.