Additional file 5: Figure S3. Expression levels of PvSPL1 in PvSPL1SRDX and rPvSPL1 overexpressing transgenic switchgrass plants were revealed by qRT-PCR. Switchgrass Ubq2 was used as the reference for normalization. PvSPL1: sum of exo- and endo-PvSPL1 transcript versions