Genome-Wide Characterization of the Gene Family in Orchardgrass and a Functional Analysis of in Responding to Drought Stress.

Drought stress is an important factor that reduces plant biomass production and quality. As one of the most important economic forage grasses, orchardgrass () has high drought tolerance. Auxin/indole-3-acetic acid () is one of the early responsive gene families of auxin and plays a key role in the response to drought stress. However, the characteristics of the gene family in orchardgrass and their potential function in responding to drought stress remain unclear. Here, 30 members were identified in orchardgrass. Segmental duplication may be an important driving force in the evolution of the gene family in orchardgrass. Some genes were induced by IAA, drought, salt, and temperature stresses, implying that these genes may play important roles in responding to abiotic stresses. Heterologous expression in yeast revealed that can reduce drought tolerance. Similarly, the overexpression of also reduced drought tolerance in transgenic , which was supported by lower total chlorophyll content and relative water content as well as higher relative electrolyte leakage and malondialdehyde content (MDA) than Col-0 plants under drought conditions. The results of this study provided valuable insight into the function of in response to drought stress, which can be further used to improve forage grass breeding programs.