MOESM5 of Switchgrass SBP-box transcription factors PvSPL1 and 2 function redundantly to initiate side tillers and affect biomass yield of energy crop WuZhenying CaoYingping YangRuijuan QiTianxiong HangYuqing LinHao ZhouGongke WangZeng-Yu FuChunxiang 2016 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.