Heterodera filipjevi Effector Hf70514 Targets TaCYPA‐1 Protein to Suppress Immunity and Enhance Susceptibility in Wheat

The cereal cyst nematode (Heterodera filipjevi) is a highly destructive pathogen responsible for significant annual economic losses. However, its effector repertoire and functions remain poorly resolved. We assembled stage-resolved transcriptomic data, prioritized secreted candidates, and validated their expression, localization, and functions. Seven candidate effectors were up-regulated at parasitism stages; in situ hybridization detected three effectors in subventral oesophageal glands and four in the dorsal oesophageal gland. Transient expression indicated that seven proteins were located in the nucleus and cytoplasm. In vitro RNAi and in planta RNAi demonstrated virulence roles for seven genes, which reduced female numbers by 28.4%-83.8% and 57.2%-87.2%, respectively. In ROS burst assays, Hf70514 and Hf107644 suppressed flg22-induced reactive oxygen species. Overexpression of Hf70514 in Arabidopsis thaliana increased the root length and plant height. Protein-protein interaction tests identified TaCYPA-1 as a wheat target of Hf70514. Transient silencing of TaCYPA-1 significantly enhanced H. filipjevi parasitism, accompanied by down-regulation of defence-related genes. Collectively, these findings expand the H. filipjevi effector compendium and suggest a model in which multiple secreted effectors suppress the PTI-associated ROS, influence plant growth, and engage specific wheat proteins to promote parasitism.