Identification and differentiation of mycorrhizal isolates of black alder by sequence analysis of the ITS region

Abstract

 Twenty isolates of black alder ectomycorrhizas were characterized on the basis of internal transcribed spacer (ITS) DNA sequences and colony morphology in pure culture. The isolates were obtained from individual, surface-sterilized mycorrhizas morphologically identified as the mycorrhizal type "Alnirhiza cystidiobrunnea". Analysis of ITS sequences allowed differentiation into four groups; three were closely related, while one isolate (BEh-Uw1) was separated by high sequence dissimilarity within the ITS1 and ITS2 spacer regions. Culture morphology was not a satisfactory differentiating feature for these four groups. An Ncbi GenBank DNA database search revealed that isolates within the three closely related ITS groups displayed high homology to ITS sequences of Tomentella sublilacina and Thelephora terrestris, whereas BEh-Uw1 had the highest sequence similarity to an ITS DNA sequence of a basidiomycete DNA isolated from bamboo leaves.