TaAP2-15, An AP2/ERF Transcription Factor, Is Positively Involved in Wheat Resistance to Puccinia striiformis f. sp. tritici

Abstract

AP2 transcription factors play a crucial role in plant development and reproductive growth, as well as response to biotic and abiotic stress. However, the role of <i>TaAP2-15</i>, in the interaction between wheat and the stripe fungus, <i>Puccinia striiformis</i> f. sp. <i>tritici</i> (<i>Pst</i>), remains elusive. In this study, we isolated <i>TaAP2-15</i> and characterized its function during the interaction. TaAP2-15 was localized in the nucleus of wheat and <i>N. benthamiana</i>. Silencing of <i>TaAP2-15</i> by barley stripe mosaic virus (BSMV)-mediated VIGS (virus-induced gene silencing) increased the susceptibility of wheat to <i>Pst</i> accompanied by enhanced growth of the pathogen (number of haustoria, haustorial mother cells and hyphal length). We confirmed by quantitative real-time PCR that the transcript levels of pathogenesis-related genes (<i>TaPR1</i> and <i>TaPR2</i>) were down-regulated, while reactive oxygen species (ROS)-scavenging genes (<i>TaCAT3</i> and <i>TaFSOD3D</i>) were induced accompanied by reduced accumulation of H₂O₂. Furthermore, we found that TaAP2-15 interacted with a zinc finger protein (TaRZFP34) that is a homolog of OsRZFP34 in rice. Together our findings demonstrate that <i>TaAP2-15</i> is positively involved in resistance of wheat to the stripe rust fungus and provides new insights into the roles of AP2 in the host-pathogen interaction.