Karstenia 40: 49- 51, 2000

Filobasidiella lutea: parasitism of Hypochnicium venereum

J. GINNS and ANNAROSA BERNICCHIA

GINNS, J. & BERNICCHIA, A. 2000: lutea: parasitism ofHypochnicium ellereum. - Karstenia 40: 49- 51. Helsinki. ISSN 0453-3402. The presence of haustoria! branches and a restricted host range suggest that Filobasi­ diella lutea is a mycoparasite. Microscopic features are illustrated from recent Italian collections. Key words: Filobasidiella, fungi, mycoparasite, systematics J. Ginns, Eastern Cereals and Oilseed Research Centre, AAFC, Ottawa, ON, KIA OC6 Canada. E-mail: [email protected]. Current address: Pacific Agriculture Research Centre, 4200 Highway 97, Summerland, British Columbia, VOH JZO, Canada Annarosa Bernicchia, /stituto di Patologia Vegetate, niversita Delgi Studi, 40126 Bologna, Italia. E-mail: abernicc@pop. agrsci. unibo. it

Introduction Collecting of wood decaying Basidiomycetes in Filobasidiella lutea P. Roberts, Mycotaxon 63: Italy yielded two specimens of an unusual, re­ 198, 1997.- Fig. 1 cently described named Filobasidiella lutea P. Roberts (1997). The fungus, until now Basidiomes effuse, inconspicuous, typically known from only six localities in England, grew several em long and broad, some nearly 0.3 mm on basidiomes of Hypochnicium vellereum (Ellis thick, adnate. Hymenial surface smooth, arid, & Cragin) Parmasto (Hyphodermataceae). The powdery, buff color. Margin indistinct. Subicu­ purpose of this paper is to confirm the connec­ lum a loose web of hyphae within the basidiome tion between F lutea and its host, document var­ of the host. iability in some morphological features, and ex­ ! system monomitic. Generative hyphae tend the geographic range. simple septate, with rare clamp connections, 2- 3 flm diam, the walls thin, hyaline, blue in cotton Methods The standard mounting media for microscopic examina­ blue, nonamyloid, nondextrinoid. Haustoria! tion of specimens of Hymenomycetes were used, i.e., branches broadly clavate, about 4 f.tm long, sim­ Melzer's reagent, 2% potassium hydroxide, aqueous ple septate at the base, most with one or two phloxine, and cotton blue in lactic acid. The formulae truncated appendages up to 2 f.tm long that are for these can be found in Boidin (1958), Hawksworth et appressed to hyphae of the host H. vellereum. a!. (1995), Hjortstam et a!. (\987) and Smith et a!. (1981). Abbreviations for herbaria where specimens are Basidia sub tended by an inverted T -shaped preserved follow Holmgren eta!. (1990). foot-cell that links each to the my- 50 GINNS & BERNICCHIA: FILOBASIDIELLA KARSTENIA 40 (2000)

one bud arising in each of the four compartments delimited by the apical septa. Basidiospores when mature globose to subglobose with the basal side slightly truncated, (5.5- ) 6.0-6.5 (- 7.0) 11m (n = 21), catenulate, the walls smooth, about 0.5 J..Lm thick, hyaline, dextrinoid, dark blue in cot­ ton blue. Spore germination not seen. Habitat. Over the hymenial surface of Hy­ pochnicium vellereum basidiomes that grew on rotted wood of Ulmus glabra Huds. and unspec­ ified of Ulmus .

Specimens examined: Italy: Parco Naz. Foreste Casen­ tinesi, Riserva di Badia Prataglia: Lama: loc. Fornino (Forli), 700 m, I.G.M. : 25,000, 265-11, on rotted wood Ulmus glabra, 17.X.l996 A. Bernicchia 6702 (DAOM, HUBO); 13 .X.1996 A. Bernicchia 6703 (HUBO) .

Discussion Some parasitic fungi have a very narrow host range and Filobasidiella lutea may be one such species. Although described only three years ago, the ten known collections ofF lutea are all on the hymenial surfaces of Hypochnicium vel­ lereum. How frequently F lutea colonizes H. vel­ lereum is uncertain. Examination of 42 collec­ tions of H. vellereum by JG (at BPI) failed tore­ veal any F lutea. Even though eight were on Ul­ mus. However, 39 were from the United States and Canada, with only one each from England, Italy and Japan. The efficiency of the mode of dispersal of Fig. 1. Filobasidiella lutea. Three basidia attached to subicular hyphae (above), and four haustoria! branches, mycoparasitic fungi is intriguing. Random dis­ the two on left attached to a hypha of the host, Hy­ persal of air-borne spores would seem to have a pochnicium vellereum, shown with shaded walls. All low chance oflanding on a host that is small and from Bernicchia 6702. widely scattered. Filobasidiella lutea 's copi­ ous, loosely attached, statimospores and both the host fungus's relatively small size (basidiomes celium. Foot-cells about 6J..Lm diamat the basidial of H vellereum are typically a few ems long and base, tapering to 3 J..Lm diam where the stem of the broad), and its habit (partially hidden basidiomes T-cell joins the main portion of the hypha, the on the lower surfaces of dead branches and stem typically 10- 20 J..Lm long, but some up to 40 stems) suggest dispersal by an insect or arachnid Jlm. Basidia clavate, (200- ) 240- 290 (- 310) x 12- vector. The ector may locate H vellereum by fol­ 13 11m (n = 11 ), each with a single clamp connec­ lowing an aroma produced by H vellereum. tion at the base, the basidial stem about 210- 240 The Italian specimens enable us to expand Jlm long and 5- 9 11m diam, cylindrical, the inflated upon several morphological features ofF lutea. basidial apex about 30 11m long, the walls thin to First, although a clamp connection is present at 0.5 J..Lm thick, hyaline, blue in cotton blue, non­ the base of each basidium, they were rare on the amyloid, nondextrinoid, cruciately septate with hyphae. The basal clamp connection strongly the septa extending 6 J..Lm into the apex of the ba­ suggests that meiosis occurs in the basidium. sidium. Sterigmata lacking. Basidiospores devel­ Second, the description of the foot-cell at the oping as obovoid buds from the basidial apex, base of each basidium confirms the connection K.L\.RSTENIA 40 (2000) GINNS & BERNICCHIA: FILOBASIDIELLA 51

between the basidium and the mycelium, and its chogastrema B. Metzler & Oberw. (1989), Syzy­ presence indicates that there is no development gospora G.W. Martin (Ginns 1986) and Tremel­ of a distinct subhymenial tissue. Third, hyphae lodendropsis (Comer) D.A. Crawford (Comer ofF lutea were 300 J.lm below the hymenial sur­ 1966). The presence of partial septa does not ap­ face in H. vellereum basidiomes. Whether hy­ pear to indicate a close relationship because two phae extended below the Hypochnicium basidi­ of the five genera are in the , one each ome is not known but it seems unlikely consider­ is in the Ceratobasidiales and Tulasnellales ing the parasitic nature ofF lutea. Fourth, the (Hawksworth et al. 1995), while Filobasidiella is haustoria! branches, best seen in phloxine placed in the (Roberts 1997). mounts because they stained deep red, were subtended by a simple septum and they were Acknowledgments: Dr. R.J. Bandoni, Vancouver, pro­ common in some areas of the host basidiome, i.e., vided constructi e comments on the systematics of this group. Dr. Peter Roberts, Kew, critically re iewed the five haustoria! branches were seen along a 30 11m manuscript. Drs. Amy Rossman and David Farr were section of a H. vellereum hypha. Fifth, cyanoph­ most cooperative during my February 1998 visit to The ily was observed in walls of spores, basidia and National Fungus Collections, Beltsville. hyphae. Roberts ( 1997) reported spore walls to be cynaophilous. Finally, the connection be­ References tween the catenate spores was fragile because Boidin, J. 1958: Essai biotaxonomique sur les Hydnes chains of spores were rarely seen, whereas indi­ Resupines et les Corticies. - Rev. Mycol. (Paris). vidual spores floating in mounts were common. Mem. hors-ser. 6: 1- 387. Roberts (1997) illustrated a disjunctor between Comer, E.J.H. 1966: The clavarioid complex of Aphe­ laria and Tremellodendropsis. - Trans. Br. Mycol. the spores in a chain, but this was not seen by us. Soc. 49: 205-211. Three species comprise the Filobasi­ Ginns, J. 1986: The genus Syzygospora (Heterobasidio­ diella. The principal morphological feature ofthe mycetes: Syzygosporaceae). - Mycologia 78: 619- genus Filobasidiella is the production by bud­ 636. ding of catenulate basidiospores from four sites Hawksworth, D.L. , Kirk, P.M., Sutton, B.C. & Pegler, D.N. 1995: Ainsworth & Bisby's dictionary of the on the apex of the basidium. Morphologically F fungi. 8th Ed. - CAB International, Wallingford, neoformans Kwon-Chung (1998) has a clamp United Kingdom. 616 pp. connection at each septum, haustoria! branches Hjortstam, K., Larsson, K.-H., & Ryvarden, L. 1987: and a stage. Whereas, F depauperata Introduction and keys. - Corticiaceae of North Eu­ rope I: 1- 59. (Petch) Samson et al. (1983) lacks these three fea­ Holmgren, P.K. , Holmgren, N.H. & Bamett,L.C. 1990: tures. Filobasidiella lutea has a clamp connec­ Index Herbariorum, Part I. 8th Ed. - Regnum Vegeta­ tion at the base of each basidium but clamp con­ bile 120: 1- 693. nections on the hyphae are rare. Like F neofor­ Kwon-Chung, K.J. 1998: 82. Filobasidiella Kwon­ mans, F lutea has haustoria! branches but these Chung. pp. 656- 663. - In: Kurtzman, C.P. & Fell, J.W. (eds.). The , A taxonomic study. 4'h ed. branches in the two species differ in morphology. Elsevier, Amsterdam. And, perhaps because it has not been cultured, a Lowy, B. 1964: A new genus of the Tulasnellaceae. - yeast stage has not been seen in F lutea. All Mycologia 56: 696- 700. three species are parasitic. Filobasidiella neo­ Metzler, B., Oberwinkler, F. & Petzold, H. 1989: Rhyn­ chogastrema gen. nov. and Rhynchogastremaceae formans is a parasite of mammals, F depauperata fam. nov. (Tremellales). - Syst. Appl. Microbial. 12: appears to be a parasite of species 280-287. that are entomopathogenic, and F lutea is also Olive, L.S. 1957: Two new genera of the Ceratobasid­ mycoparasitic (Kwon-Chung 1998, Roberts 1997, iaceae and their phylogenetic significance. - Amer. J. Samson et al. 1983). Bot. 44: 424-435. Roberts, P. 1997: New Heterobasidiomycetes from The occurrence of basidia with a partially sep­ Great Britain. Mycotaxon 63 : 195- 216. tate apex is unusual. Howe er, in Filobasidiella Samson, R.A., Stalpers, J.A. & Weijman A.C.M. 1983: they are known in F lutea, where all basidia we On the of the entomogenous fungus Filo­ observed were partially septate, and in F depau­ basidiella arachnophila. - Antonie van Leeuwenhoek 49: 447-456. perata some basidia are partially septate(Kwon­ Smith, A.H., Smith, H.V. & Weber, N.S. 1981: How to Chung 1998). Such septa also occur in some spe­ know the non-gilled mushrooms. 2nd ed. - W.C. cies of the genera Metabourdotia L.S. Olive Brown Co., Dubuque, Iowa. 324 pp. (1957), Pseudotulasnella Lowy (1964), Rhyn-