VRS2 Regulates Hormone-Mediated Inflorescence Patterning in Barley

Plant architecture has clear agronomic and economic implications for crop plants, such as wheat and barley, as it is a critical factor for determining grain yield. Despite this, only little molecular information is available about how grain-bearing inflorescences, called spikes, are formed and maintain their regular, distichous pattern. 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 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.