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Fine‐scale spatial distribution of orchid mycorrhizal fungi in the soil of host‐rich grasslands
Author(s) -
Voyron Samuele,
Ercole Enrico,
Ghig Stefano,
Perotto Silvia,
Girlanda Mariangela
Publication year - 2017
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.14286
Subject(s) - biology , botany , orchidaceae , grassland , spatial distribution , glomeromycota , host (biology) , mycorrhiza , ecology , symbiosis , geography , remote sensing , genetics , bacteria
Summary Mycorrhizal fungi are essential for the survival of orchid seedlings under natural conditions. The distribution of these fungi in soil can constrain the establishment and resulting spatial arrangement of orchids at the local scale, but the actual extent of occurrence and spatial patterns of orchid mycorrhizal (OrM) fungi in soil remain largely unknown. We addressed the fine‐scale spatial distribution of OrM fungi in two orchid‐rich Mediterranean grasslands by means of high‐throughput sequencing of fungal ITS 2 amplicons, obtained from soil samples collected either directly beneath or at a distance from adult Anacamptis morio and Ophrys sphegodes plants. Like ectomycorrhizal and arbuscular mycobionts, OrM fungi (tulasnelloid, ceratobasidioid, sebacinoid and pezizoid fungi) exhibited significant horizontal spatial autocorrelation in soil. However, OrM fungal read numbers did not correlate with distance from adult orchid plants, and several of these fungi were extremely sporadic or undetected even in the soil samples containing the orchid roots. Orchid mycorrhizal ‘rhizoctonias’ are commonly regarded as unspecialized saprotrophs. The sporadic occurrence of mycobionts of grassland orchids in host‐rich stands questions the view of these mycorrhizal fungi as capable of sustained growth in soil.