Changes in the Abundance and Community Complexity of Soil Nematodes in Two Rice Cultivars Under Elevated Ozone

The atmospheric ozone concentrations have substantially increased in the surface layer over the past decades, and consequently exhibited a strong influence on soil microbial communities and functions. However, the effect of elevated ozone (eO₃) on the abundance, diversity, and structural complexity of soil nematode communities are elusive under different rice (Oryza sativa L.) cultivars. Here, the soil nematode community was investigated in two rice cultivars (Hybrid, Shanyou 63 vs. Japonica, Wuyujing 3) under open-top chambers (OTC) with control and eO₃ conditions. The results showed that the abundance of soil nematode community was altered by eO₃, but the responses were dependent on crop cultivars. The eO₃ decreased the total abundance and simplified the network complexity of the soil nematode community for both cultivars. However, eO₃ increased the abundance of c-p 4 in Shanyou 63, rather than Wuyujing 3, indicating that the hybrid rice cultivar could tradeoff the adverse impacts of eO₃ on the functional group of soil nematodes. Similarly, bacterivores belonging to K-strategy (c-p 4) increased under eO₃ in Shanyou 63, suggesting that the soil food web formed a bacteria-dominated channel under eO₃ for the hybrid rice cultivar. This study shed new light on the critical importance of rice cultivars in shaping the impacts of eO₃ on the soil micro-food web. Therefore, breeding and biotechnological approaches may become valuable pathways to improve soil health by shaping the community structures of the soil micro-food web in response to climate change in the future.