Hydrogen cyanide, a key plant defense, as a potential driver of root-associated nematode communities along urbanization gradients

Introduction Plant chemical defenses can influence the distribution, community composition, and abundance of soil biota. Urbanization plays a key role in shaping biotic communities either directly through changes properties or indirectly via plant characteristics such as defense traits. The effects urbanization on structure aboveground plant-associated have been studied, yet their belowground root-associated are poorly understood. Methods Here we sampled white clover ( Trifolium repens L.) leaves roots along urban–rural gradients cities Antwerp Ghent, Belgium. We measured production hydrogen cyanide (HCN) leaves, known trait against herbivores, abundances different feeding guilds nematodes associated with roots. Results found that HCN decreased increasing levels both cities. was significantly correlated shifts nematode but not Ghent. Responses trophic groups to were highly dependent clovers’ production, especially Changes channel ratio indicated urban more strongly dominated by fungivorous nematodes. Discussion Our results demonstrate is driving phenotypic nematodes, well interact. mechanisms could thus help elucidate biota communities. As strong differences existed between two studied cities, particular should be taken into account better understand direction strength driven urbanization.