Exchange of Noncoding Small RNA Between Miscanthus x giganteus and Sipha flava

Cross-species communication through small RNA (sRNA) has been implicated between species across kingdoms, often between symbiotes or parasites and their hosts through RNAi mechanisms. However, there has been no evidence of this exchange of sRNA between Sipha flava (yellow sugarcane aphid) and Miscanthus X giganteus (Mxg). To determine whether micro-RNA (miRNA) is transferred from S. flava into Mxg during infestation of S. flava on Mxg leaves, small RNA-seq was performed on samples collected from infested and healthy leaves of an infested plant, and leaves of a healthy plant. A differential expression analysis showed that S. flava miRNA was highly expressed in infested leaves of Mxg, while showing little or no expression in healthy samples – the most significant of which included miR-1, miR-184, miR-263, and miR-276. Predicting the mRNA targets of these significantly expressed miRNAs in Mxg will elucidate the purpose of the miRNA transfer from S. flava to Mxg. Our current findings are the beginning steps for determining whether there is cross-communication in the form of sRNA between S. flava and Mxg. Uncovering this mechanism of sRNA exchange is essential to revealing molecular bases for the cross-species interactions.