Entrophospora baltica

Blaszk.

In PVLG

SPORES single in the soil; develop inside the neck of a sporiferous saccule; pale orange (6A3) to orange (6A8); globose to subglobose; (110-)177(-220) µm diam; sometimes ovoid; 135-210 x 170-240 µm. Spores and sometimes sporiferous saccules covered with a hyphal mantle. Some spores were associated with Glomus-like spores.

 

 

In PVLG

Mantle hyaline to pale yellow (3A3); 10-40 µm thick; composed of hyaline to pale yellow (3A3) interwoven, sinuous hyphae; 2.5-10 µm wide, with walls 1-2 µm thick; staining lake red (9C8) in Melzer's reagent.

 

 

SUBCELLULAR STRUCTURE OF SPORES composed of a spore wall and one germinal wall.

All in PVLG

Spore wall consists of four layers (swl1-4).

Layer 1 evanescent, hyaline, (1.5-)2.0(-2.5) µm thick.

Layer 2 permanent, pale orange (3A3) to orange (6A8), (1.1-)1.3(-1.7) µm thick, ornamented with evenly distributed warts, 0.6-0.8 µm high.

Layer 3 laminate, hyaline, (1.5-)2.1(-2.7) µm thick.

Layer 4 flexible to semi-flexible, hyaline, 0.5-0.8 µm thick, usually tightly adherent to the lower surface of layer 3, and, hence, difficult to detect.

Germinal wall consists of three layers (gwl1-3).

In PVLG

Layer 1 flexible, (0.5-)1.0(-1.3) µm thick.

Layer 2 flexible, coriaceous, (2.1-)2.7(-3.3) µm thick.

Layer 3 flexible to semi-flexible, hyaline, 0.5-0.8 µm thick, sometimes separating from layer 2 in vigorously crushed spores.

In PVLG

CICATRIX. Two circular scars indicating the region of contact between spore and saccule neck are present. A scar proximal to the saccule is 15.0-32.5 µm diam when seen in a plane view, sometimes with a cylindrical or funnel-shaped stalk (see above), when observed in a cross-view. A scar distal to the saccule is 13.0-16.0 µm diam.

 

 

In PVLG
SPORIFEROUS SACCULE hyaline to pale yellow (3A3); globose to subglobose; (100-)170(-210) µm diam.
Wall of sporiferous saccule composed of a granular, hyaline, 0.5-0.8 µm thick outer layer adherent to a smooth, hyaline inner layer, ca. 1 µm thick.

Spores occasionally with a cylindrical or funnel-shaped stalk projecting inward the sporiferous saccule and with a short subtending hypha, usually present at the opposite of the saccule. Stalk maize yellow (4A6) to deep yellow (4A8); 10-70 µm long, 15-35 µm wide at the spore base, broadened up to 112 µm when funnel-shaped, with a laminate wall, 3.4-3.9 µm thick; stalk surrounding a hole, 15-32.5 µm diam. Subtending hypha pale yellow (4A3); 15-25 µm long, 13-16 µm wide at the spore base, with walls 2.8-3.7 µm thick at the spore base. Saccule collapsing at maturity. Spores and saccule not reacting in Melzer's reagent.

GERMINATION. Not observed.

MYCORRHIZAE. In the field, spores of E. baltica have been associated with vesicular-arbuscular mycorrhizal roots of Ammophila arenaria (L.) Link, Elymus arenarius L., Helichrysum arenarium (L.) Moench, Hieracium umbellatum L., Lathyrus japonicus subsp. maritimus (L.) P. W. Ball., and Petasites spurius (Retz.) Rchb. (Blaszkowski et al. 1998; Tadych and Blaszkowski 2000). Although E. baltica produced spores in trap cultures, many attempts to establish mycorrhizae of this fungus in one-species cultures failed. No literature data exists of the properties of mycorrhizae of E. baltica.

DISTRIBUTION. Entrophospora baltica has originally been recovered from among roots of A. arenaria and P. spurius colonizing dunes adjacent to Swinoujscie (53º55'N, 14º14'E) in north-western Poland (Blaszkowski et al. 1998). Later, this fungus has been found associated with different plant species (see above) growing in maritime dunes of the Slowinski National Park (54º45’N, 17º26’E; Tadych and Blaszkowski 2000).

Apart from Poland, E. baltica has also been revealed at several Alpine elevations in Switzerland and among the mycorrhizal community of forest ecosystems near Valdina in Southern Chile (Sieverding and Oehl 2006).

NOTES. Spores of E. baltica are distinctive because of both being enveloped in a sinuate hyphal mantle and having a unique wall structure. The mantle consists of tightly interwoven thin-walled hyphae that evenly cover the spores and sometimes occur on the sporiferous saccule. The presence of short hyphae on the surface of immature spores and the lack of their evanescent outermost wall layer 1 in crushed spores with a separated mantle suggest this mantle to be formed by hyphae developing from spore wall layer 1. Spore wall layer 1 is visible in most intact spores. Spore wall layer 2 is always present and sometimes detaches from spore wall layer 3 in uncrushed spores mounted in lactic acid. Spore wall layer 3 consists of two to three laminae usually separating from each other in vigorously crushed spores. Spore wall layer 4 has not been included in the original description of the species (Blaszkowski et al. 1998), but it has been reported to exist by Sieverding and Oehl (2006). Germinal wall layer 1 is a typical membranous wall. The coriaceous layer 2 of this wall is flexible and does not crack, despite it is much thicker than the flexible germinal wall layer 1. Germinal wall layer 3 has not been presented in the original protologue (Blaszkowski et al. 1998).

Entrophospora baltica differs greatly from other species of the Glomeromycota forming entrophosporioid spores (Intraspora and Kuklospora spp.) in appearance, the morphology of the spore ornamentation, and in spore wall structure. None of the species forms spores enveloped in a hyphal mantle. Entrophospora infrequens, now the only other member of the genus Entrophospora, and Kuklospora kentinensis produce spores with an ornamented laminate spore wall layer. However, the ornamentation of the former fungus consists of vacuolated projections (Ames and Schneider 1979; Blaszkowski 1989; Hall 1977; Sieverding and Oehl 2006), and that of the latter species is composed of evenly distributed pits (Morton 2000; Sieverding and Oehl 2006; Wu et al. 1995). In contrast, spores of E. baltica are ornamented with warts present on a permanent, unit spore wall layer adherent to a laminate layer. Kuklospora colombiana and Intraspora schenckii may be separated readily from E. baltica because of having smooth spores of a different subcellular structure (Schenck et al. 1984; Sieverding and Oehl 2006; Sieverding and Toro 1987). Additionally, spores of E. schenckii are hyaline (Sieverding and Toro 1987; Schenck et al. 1984), whereas those of E. baltica are coloured.

Arbuscular fungi having spores enveloped in a sinuate hyphal mantle also are Glomus mortonii, Gl. sinuosum, and Gl. tortuosum (Almeida and Schenck 1990; Bentivenga and Hetrick 1991; Schenck and Smith 1982). However, the mantle of Gl. mortonii and Gl. sinuosum consists of thick-walled hyphae, not reacting in Melzer's reagent. The mantle hyphae of E. baltica are thin-walled and stain lake red in this reagent. Although the mantle of Gl. tortuosum is composed of thin-walled hyphae, this fungus produces spores with a spore wall composed of only one laminate layer (Morton 2000). Spores of Glomus spp. originate terminally from subtending hyphae (Morton and Benny 1990). Additionally, Gl. mortonii and Gl. sinuosum produce spores in sporocarps. In contrast, E. baltica spores develop within the neck of a sporiferous saccule and occur singly in the soil.

REFERENCES

Almeida R. T., and N. C. Schenck. 1990. A revision of the genus Sclerocystis (Glomaceae, Glomales). Mycologia 82, 703-714.

Ames R. N., Schneider R. W. 1979. Entrophospora, a new genus in the Endogonaceae. Mycotaxon 8, 347-352.

Bentivenga S. P., and Hetrick B. A. D. 1991. Glomus mortonii sp. nov., a previously undescribed species in the Glomaceae isolated from the tallgrass prairie in Kansas. Mycotaxon 42, 9-15.

Blaszkowski J. 1989. Polish Endogonaceae. I. Acaulospora bireticulata, Entrophospora infrequens, Glomus caledonium, and Scutellispora pellucida. Karstenia 29, 1-10.

Blaszkowski J., Madej T., Tadych M. 1998. Entrophospora baltica sp. nov. and Glomus fuegianum, two species in the Glomales from Poland. Mycotaxon 68, 165-184.

Morton J. B. 2000. International Culture Collection of Arbuscular and Vesicular-Arbuscular Mycorrhizal Fungi. West Virginia University. http://www.invam.caf.wvu.edu/.

Morton J. B., Benny G. L. 1990. Revised classification of arbuscular mycorrhizal fungi (Zygomycetes): a new order, Glomales, two new suborders, Glomineae and Gigasporineae, and two new families, Acaulosporaceae and Gigasporaceae, with an emendation of Glomaceae. Mycotaxon 37, 471-491.

Hall I. R. 1977. Species and mycorrhizal infections of New Zealand Endogonaceae. Trans. Br. Mycol. Soc. 68, 341-356.

Schenck N. C., Smith G. S. 1982. Additional new and unreported species of mycorrhizal fungi (Endogonaceae) from Florida. Mycologia 74, 77-92.

Schenck N. C., Spain J. L., Howeler R. H. 1984. Several new and unreported vesicular-arbuscular mycorrhizal fungi (Endogonaceae) from Colombia. Mycologia 76, 685-699.

Sieverding E., Oehl F. 2006. Revision of Entrophospora and description of Kuklospora and Intraspora, two new genera in the arbuscular mycorrhizal Glomeromycetes. J. Appl. Bot. Food Qual. 80, 69-81.

Sieverding E., Toro S. T. 1987. Entrophospora schenckii: a new species in the Endogonaceae from Colombia. Mycotaxon 28, 209-214.

Tadych M., Blaszkowski J. 2000. Arbuscular fungi and mycorrhizae (Glomales) of the Slowinski National Park, Poland. Mycotaxon 74, 463-483.

Wu C.-G., Liu Y.-S., Hwuang Y.-L., Wang Y.-P., Chao C.-C. 1995. Glomales of Taiwan: V. Glomus chimonobambusae and Entrophospora kentinensis, spp. nov. Mycotaxon 53, 283-294.