Root system adaptations of Arabidopsis to Nematode Stress: An Interspecific Comparison

Plants mitigate biotic stress through disease tolerance mechanisms, such as adventitious lateral root growth. However, the molecular and physiological processes underlying disease tolerance remain poorly understood. Nematode-induced stress is highly heterogeneous, affecting root tissues over time. Since nematodes differ in migratory and feeding strategies, plant responses may vary accordingly. Here, we investigated how Arabidopsis thaliana responds to three nematode species with distinct behaviors: the root-lesion nematode Pratylenchus penetrans, the cyst nematode Heterodera schachtii, and the root-knot nematode Meloidogyne incognita. Using high-throughput phenotyping, we quantified plant responses to increasing nematode densities. All species caused a density-dependent decline in green canopy area, but this decline was stronger for P. penetrans and H. schachtii than for M. incognita. However, despite similar reductions in canopy area, H. schachtii had a more pronounced effect on plant growth. Moreover, while P. penetrans and H. schachtii cause similar root cortex damage, adaptive root responses to P. penetrans differed significantly. P. penetrans-infected roots had longer secondary roots, suggesting a distinct compensatory mechanism. These findings suggest root system adaptations to nematode infection are species specific, reflecting differences in damage location and type. Understanding these mechanisms could provide insights into plant disease tolerance strategies.