Complementary effects of beneficial and non‐beneficial mycorrhizal fungi on root phosphatase activity: A mycorrhizal “White Album” effect

Mycorrhizal fungi are diverse, with strains differing in the magnitude and types of benefits provided to their hosts. In mixture, mycorrhizal strains that have complementary functions could provide their hosts with greater benefits than any constituent strain in isolation. Conversely, mycorrhizal strains could also interfere with one another, competing for host resources, providing less benefits than the most beneficial strain. The actual, realized effects are likely a composite of these complementary and competitive effects. Spatial structure in the root system may allow plants to benefit from complementary benefits while reducing competition among mycorrhizal strains. I tested the role of spatial structure using a species of plant from the family Podocarpaceae, which host arbuscular mycorrhizal fungi inside both finely separated nodules and longer, contiguous sections of fine root. In root nodules, co‐inoculation with both growth‐promoting and non‐growth‐promoting arbuscular mycorrhizal fungi resulted in complementary increases in aggregate root/fungal phosphatase activity. This complementary effect was not present in longer, contiguous sections of fine root or in either root type with P‐fertilization. I dub this interaction a ‘White Album effect’, a reference to the Beatles' best‐selling album, where complementary effects of single artists were only revealed when individual conflicts were avoided by separating band members and synthesizing their contributions in post‐production. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog.