Interaction of Heterodera avenae with Soil Temperature and Its Effect on Wheat Root Colonization

Abstract

Interaction of Heterodera avenae with soil temperature and its effect on wheat root colonization was investigated to elucidate how thermal regimes regulate nematode infectivity, survival, and host invasion dynamics in cereal-based agroecosystems. Field surveys and controlled pot experiments were conducted under a range of constant and fluctuating soil temperatures, and nematode penetration rates, development stages, and root colonization intensity were quantified in wheat seedlings. Results indicated that soil temperature exerted a strong regulatory influence on the life cycle progression of H. avenae, with moderate temperature ranges significantly enhancing juvenile activity, root penetration, and successful establishment within cortical tissues. Lower temperature conditions delayed hatching and reduced mobility of second-stage juveniles, resulting in reduced infection rates and limited root colonization. In contrast, elevated temperatures beyond the optimal threshold negatively affected survival and reduced successful host invasion, likely due to thermal stress and disruption of host–parasite synchronization. Root colonization was found to be closely associated with root growth rate and rhizosphere activity, with peak infestation occurring during early seedling stages under favorable thermal conditions. The study also highlighted that temperature-driven changes in nematode development influenced gall formation and feeding site establishment, ultimately affecting wheat root architecture and plant vigor. These findings emphasize the critical role of soil temperature as a determinant of H. avenae population success and infection dynamics. The results provide valuable insights for predicting disease risk and developing temperature-based forecasting models for integrated nematode management in wheat production systems.