Key (ARF) genes constraining wheat tillering of mutant .

Tillering ability is a key agronomy trait for wheat ( L.) production. Studies on a wheat mutant () showed that played an important role in tillering of wheat. In this study, a total of 67 ARF family members were identified and clustered to two main classes with four subgroups based on their protein structures. The promoter regions of () genes contain a large number of -acting elements closely related to plant growth and development, and hormone response. The segmental duplication events occurred commonly and played a major role in the expansion of . The gene collinearity degrees of the between wheat and other grasses, rice and maize, were significantly high. The evolution distances among determine their expression profiles, such as homoeologous genes have similar expression profiles, like , and their homoeologous genes. The expression profiles of in various tissues or organs indicated , , and and their homoeologous genes played basic roles during wheat development. , , , , , , and their homoeologous genes probably played basic roles in tiller development. qRT-PCR analyses of 20 representative genes revealed that the abnormal expressions of and were major causes constraining the tillering of . Indole-3-acetic acid (IAA) contents in were significantly less than that in Guomai 301 at key tillering stages. Exogenous IAA application significantly promoted wheat tillering, and affected the transcriptions of . These data suggested that as well as IAA signaling were involved in controlling wheat tillering. This study provided valuable clues for functional characterization of ARFs in wheat.