VRS2 regulates hormone-mediated inflorescence patterning in barley

In the present study, we elucidate the molecular and hormonal role of the Six-rowed spike 2 (Vrs2) — a SHORT INTERNODES (SHI) transcriptional regulator during barley inflorescence and shoot development. Here we show that Vrs2 is specifically involved in floral organ patterning and phase duration by maintaining hormonal homeostasis and gradients during normal spike development; but similarly influenced plant stature traits. Furthermore, we establish a first link between the SHI-protein family and sucrose metabolism during organ growth and development, which may have implications for deeper molecular insights into crops' inflorescence and plant architecture. Differential gene expression study between BW-NIL(vrs2.e) vs. Bowman was done on the extracted RNA from immature shoot apices to infer the differences at level of expression at early spike developmental stages (triple mound (TM), glume primordia (GP), stamen primordia (SP), awn primordia (AP)). For microarray study, the immature shoot apices collected from BW-NIL(vrs2.e) and WT progenitor Bowman at AP, GP, SP and TM were used. The RNA from these tissues was extracted using Plant Mini RNA kit (Qiagen, Hilden, Germany) following the manufacturer's protocol. The quantity of RNA was measured using the NanoDrop ND-1000 (Peqlab, Erlangen, Germany). The quality of the extracted RNA was verified with a Bioanalyzer 2100 device (Agilent Technologies, Santa Clara, CA, USA). The RNA was labeled through the application of a Low Input Quick Amp Labeling kit (Agilent Technologies). The labeled cRNA samples were subsequently purified using RNeasy mini spin columns (Qiagen) and 600ng of Cy3-labeled, amplified cRNA were hybridized, following the manufacturer's protocol, to a custom-synthesized 60k Barley Microarray (Agilent Technologies).