P-084 - Unravelling the role of a regulatory hub of wheat susceptibility to Fusarium head blight in bread wheat

Fusarium Head Blight (FHB), caused by Fusarium graminearum, is a major disease affecting wheat heads. The infection process leverages unconventional mechanisms that exploit host susceptibility factors in the early stages, diverging from classical determinants of host resistance. Our previous studies have revealed a conserved regulatory network across multiple wheat cultivars, linking fungal effector expression with core host-response modules and highlighting genes that act either upstream or downstream of the wheat response. In this study, two key genes of this network were selected for functional validation using the Virus-Induced Gene Silencing (VIGS) method in spikes. The first gene belongs to the WRKY transcription factor family and is thought to be targeted by nuclear effectors of F. graminearum. It acts as a master regulator involved in responses to various stresses due to its broad impact on downstream gene regulation. The second gene belongs to the STP family and functions downstream of the WRKY gene. It plays a key role in sugar transport and is involved in various biotic stress responses. Silencing both genes prior to fungal infection resulted in a significant one-third reduction in FHB symptom severity, suggesting that both the WRKY and STP genes contribute to wheat susceptibility to FHB. These findings support their key roles in disease development and provide promising targets for breeding programs aimed at achieving durable FHB resistance.