Nested PCR detection of Archaea in defined compartments of pine mycorrhizospheres developed in boreal forest humus microcosms.

Archaea colonising defined compartments of Scots pine Suillus bovinus or Paxillus involutus mycorrhizospheres developed in forest humus-containing microcosms were investigated by nested polymerase chain reaction (PCR), cloning, restriction fragment length polymorphism (RFLP) and sequencing. Archaea representing six RFLP groups were detected in the system. Sequence analysis of clones representing the different RFLP types confirmed the presence of novel Finnish forest soil Crenarchaeota. Archaeal sequences were identified from mycorrhizas of both P. involutus and S. bovinus, at the margins of the external mycelium and in uncolonised humus but not from non-mycorrhizal short roots. Fungal and compartment-specific crenarchaeal occupation of mycorrhizospheres is discussed in relation to bacterial community distribution in similar systems.