Key wheat <i>GRF</i> genes constraining wheat tillering of mutant <i>dmc</i>

Abstract

Tillering is a key agronomy trait for wheat (<i>Triticum aestivum</i> L.) production. Previously, we have reported a dwarf-monoculm wheat mutant (<i>dmc</i>) obtained from cultivar Guomai 301 (wild type, WT), and found growth regulating factors (GRFs) playing important roles in regulating wheat tillering. This study is to systematically investigate the roles of all the wheat <i>GRFs</i> (<i>T. aestivum GRFs</i>, <i>TaGRFs</i>) in regulating tillering, and screen out the key regulators. A total of 30 <i>TaGRFs</i> were identified and their physicochemical properties, gene structures, conserved domains, phylogenetic relationships and tissue expression profiles were analyzed. The expression levels of all the <i>TaGRFs</i> were significantly lower in <i>dmc</i> than those in WT at early tillering stage, and the abnormal expressions of <i>TaGRF2-7</i>(A, B, D), <i>TaGRF5-7D, TaGRF10-6</i>(A, B, D) and <i>TaGRF11-2A</i> were major causes constraining the tillering of <i>dmc</i>. The transcriptions of <i>TaGRFs</i> were significantly affected by exogenous indole acetic acid (IAA) and gibberellin acid (GA3) applications, which suggested that <i>TaGRFs</i> as well as IAA, GA signaling were involved in controlling wheat tillering. This study provided valuable clues for functional characterization of <i>GRF</i> genes in wheat.