First report of Rhizopogon roseolus in Iran

Rhizopogon is a hypogeous fungal genus that grows in an ectomycorrhizal symbiosis mostly with members of the Pinaceae family and its worldwide distribution correlates with natural and exotic Pinaceae forests. In Iran, Rhizopogon species have received scant attention from collectors in the past and have not been adequately collected. Few older studies, report the presence of R. luteolus (Saber 1999), and R. vulgaris in Iran (Ershad 2009). However, the accuracy of the species identification merely on the basis of morphological features is questionable. Rhizopogon roseolus is common in northwestern United States USA (Coker & Couch 1928, Harrison & Smith 1968). So far, it has been reported from, Finland (Schulmann 1955), Chile (Garrido 1986), Brazil (Baseia & Milanez 2002), Poland (Iwanski et al. 2006), Spain (Dominguez-Nunez et al. 2013) and New Zealand. In this study, seven specimens associated with roots of Pinus eldarica based on morphological and molecular characteristics were examined. Basidiocarps were hypogeous, globose, subglobose or irregular with different sizes (up to 10 cm in diam.) (Fig. 1A). Peridium was smooth and orange. Gleba was white to olive (Fig. 1B). Fresh mature basidiocarp not reacting in iodine. The basidia were club-shaped and 15–20 × 6–8 μm (Fig. 1C). Columella absent and paraphyses about 12–18 × 5–9 μm (Fig. 1D). The basidiospores ellipsoidal, smooth, hyaline, 6–8 × 3–4 μm, often contain two guttulae inside and falsely septate (Fig. 1E). All DNA sequences of Rhizopogon (accession numbers: KP202698 to KP202700) showed 100% homology with valid sequences previously identified and deposited in GenBank. Phylogenetic trees constructed based on ITS sequences showed that, all Iranian specimens are in the same branch in a clade with R. roseolus reported from other authors (Fig. 2). Rhizopogon roseolus, R. Burlinghamii,and R. vulgaris form distinct clades which were well-supported by bootstrap value (78% MP). This is the first report of R. roseolus and its host plant from Iran.