Soil compaction effects on arbuscular mycorrhizal symbiosis in wheat depend on host plant variety

Abstract

Background and aims Supporting arbuscular mycorrhizal (AM) nutrient acquisition in crops may reduce the need for fertilizer inputs, leading to more cost effective and sustainable crop production. In wheat, AM fungal responsiveness and benefits of symbiosis vary among varieties. This study explored the role of soil compaction in this variation. Methods We examined in a field experiment how soil compaction affects AM fungal colonization and biomass in five spring wheat varieties, and how these varieties differ in their AM-mediated phosphorus (P) uptake. We also studied soil properties, and AM fungal community composition in roots and soil. Results Soil compaction increased AM fungal colonization in the variety Alderon, characterized by root traits that indicate inefficient P uptake. Wheat P concentration and P:N ratio in Alderon and Diskett increased with increased root AM fungal colonization and biomass. In Diskett, which is the most cultivated spring wheat variety in Sweden and has intermediate root traits, total P content per m 2 also increased with root AM fungal colonization and biomass. Conclusions Some wheat varieties, potentially those characterized by P inefficient root traits, such as Alderon, may depend more on AM-mediated P uptake in compacted than in non-compacted soil. Increased P uptake with increased AM fungal colonization in Diskett suggests that efficient root and AM-mediated nutrient uptake can occur simultaneously in a modern variety. Breeding varieties that use roots and AM symbiosis as complementary strategies for nutrient uptake could improve nutrient uptake efficiency and help farmers achieve stable yields in varying conditions.

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