Functional Characterization of a Putative Glycine max ELF4 in Transgenic Arabidopsis and Its Role during Flowering Control

Abstract

Flowering is an important trait in major crops like soybean due to its direct relation to grain production. The circadian clock mediates the perception of seasonal changes in day length and temperature to modulate flowering time. The circadian clock gene <i>EARLY FLOWERING 4</i> (<i>ELF4</i>) was identified in <i>Arabidopsis thaliana</i> and is believed to play a key role in the integration of photoperiod, circadian regulation, and flowering. The molecular circuitry that comprises the circadian clock and flowering control in soybeans is just beginning to be understood. To date, insufficient information regarding the soybean negative flowering regulators exist, and the biological function of the soybean <i>ELF4</i> (<i>GmELF4</i>) remains unknown. Here, we investigate the <i>ELF4</i> family members in soybean and functionally characterize a <i>GmELF4</i> homologous gene. The constitutive overexpression of <i>GmELF4</i> delayed flowering in Arabidopsis, showing the <i>ELF4</i> functional conservation among plants as part of the flowering control machinery. We also show that <i>GmELF4</i> alters the expression of Arabidopsis key flowering time genes (<i>AtCO</i> and <i>AtFT</i>), and this down-regulation is the likely cause of flowering delay phenotypes. Furthermore, we identified the <i>GmELF4</i> network genes to infer the participation of <i>GmELF4</i> in soybeans. The data generated in this study provide original insights for comprehending the role of the soybean circadian clock ELF4 gene as a negative flowering controller.