Contemporary Monograph of the Rhizophydiales Based on Molecular Phylogeny, Zoospore Ultrastructure and Thallus Morphology

 

Rhizophydiales Letcher
Mycological Research 110: 908 (2006).
MycoBank no.: MB 511767

Sporangium epibiotic or endobiotic, inoperculate or operculate, monocentric or colonial. In the zoospore a microtubular root composed of one or more microtubules may or may not be present, but when present, extends from one side of the kinetosome, usually in a parallel array, to a cisterna on the lipid globule surface; ribosomes are enclosed by a system of double membranes; mitochondria, microbodies, lipid globules, and membrane cisterna are typically associated as a MLC (Microbody-Lipid globule Complex); the non-flagellated centriole and kinetosome lie parallel or slightly angled toward each other and are connected by fibrillar material; a kinetosome associated structure, a spur or shield, may or may not be present, adjacent to the kinetosome; the base of the flagellum proper lacks an electron-opaque plug.

Occurring primarily in aquatic systems as parasites of algae, and in soil primarily as saprotrophs of pollen and to a lesser extent, keratin, chitin, and cellulose.

Currently in Rhizophydiales are 10 families, 14 genera, and several described taxa that are family incertae sedis. The order, families, and genera have been delineated on the bases of molecular monophyly and specific zoospore ultrastructure, and type species have been described on the basis of morphology.

The type for the order is the genus Rhizophydium Schenk.

 

Families and Genera

Alphamycetaceae Angulomycetaceae Aquamycetaceae Globomycetaceae Gorgonomycetaceae Kappamycetaceae Pateramycetaceae Protrudomycetaceae Rhizophydiaceae Terramycetaceae Family incertae sedis

 

Rhizophydiaceae Letcher
Mycological Research 110: 909 (2006).
MycoBank no.: MB 82157

Sporangium spherical at maturity, with multiple discharge pores or papillae. Rhizoids endobiotic, extensive, branched. Zoospore contains a single lipid globule partially covered with an inconspicuous fenestrated cisterna that covers only a small portion of the lipid globule; a microtubular root is present; kinetosome and non-flagellated centriole are parallel and are connected by fibrillar material with a zone of convergence approximately 0.075 micrometers in width centrally located between the two structures; kinetosome-associated structure (KAS) present as a laminated, curved spur.

Saprotrophic on pollen or keratin; common in aquatic and terrestrial habitats.

Rhizophydium is the type for the family.


Rhizophydium Schenk
Verhandlungen Physikalisch-Medizinische Gesellschaft. Wuerzburg, A.F. 8: 235-259 (1858).
MycoBank no.: MB 20484
Description as for family.

Rhizophydium globosum(A. Braun) Rabenh. (Type)
Fl. Eur. Alg. 3:280 (1868).
MycoBank no.: MB 219738

Basionym:
Chytridium globosum A. Braun
Abhandl. Berlin Akad.: 34 (1855).

Type:
A. Braun, Abhandl. Berlin Akad. 1855: 34, pl. 2, figs 14-20 (1855-holotype); Letcher et al., Mycol Res. 110: 907 figs. 3K-P, 911, fig. 7 (2006).

Description as for genus. Sporangium spherical, 10-30 micrometers in diameter, with 1 to 7 protruding discharge papillae. Resting spore spherical with the outer surface smooth when on pollen, or covered with small spines when on Oedogonium sp.

GenBank LSU rDNA sequence DQ485551, ITS1-5.8S-ITS2 rDNA sequence DQ485616.

Rhizophydium brooksianum Longcore
Mycologia 96: 163, figs. 1-21 (2004)
Description as for genus. Sporangium spherical, with multiple, evenly distributed discharge pores 4-10 micrometers in diameter, appearing as lenticular protrusions before discharge.
Rhizoidal system composed of many closely spaced and highly branched axes, with rhizoids extending to 1.75X the diameter of the mature sporangium. Zoospore spherical, 4-5 micrometers in diameter, with one visible lipid globule; flagellum about 27 micrometers long. Resting spores 12-17 micrometers diameter with one large refractive globule.

Isolated from soil on pollen.

GenBank SSU rDNA sequence AF164268-9, LSU rDNA sequence AY349086, ITS1-5.8S-ITS2 sequenceDQ485613; mitochondrial genome NCBI # NC_003053.

Terramycetaceae Letcher
Mycological Research 110: 911 (2006).
MycoBank no.: MB 82156
Sporangium spherical to angular at maturity, with multiple, slightly or prominently raised discharge papillae. Rhizoids robust and branched. Zoospore contains a single lipid globule partially covered by a simple or fenestrated cisterna; kinetosome and non-flagellated centriole are connected by fibrillar material with a zone of convergence of fibrils approximately 0.010-0.025 micrometers in width centrally located between the two structures; kinetosome-associated structure (KAS) present as a solid, non-laminar, curved spur.

Saprotrophic on pollen or keratin; primarily from terrestrial habitats.

Terramycetaceae contains two genera, Terramyces and Boothiomyces. Terramyces is the type for the family.


Terramyces Letcher
Mycological Research 110: 911 (2006).
MycoBank no.: MB 29046
Description as for family. Sporangium angular, with multiple, slightly raised discharge papillae. Zoospore contains a single lipid globule partially covered with a simple cisterna; kinetosome-associated structure (KAS) is a spur terminated with a spherical knob.


Terramyces subangulosum (A. Braun) Letcher (Type)
Mycological Research 110: 911 (2006).
MycoBank no.: MB 334766

Basionym:
Chytridium subangulosum A. Braun
Abhandl. Berlin Akad.: 44 (1855).

Type:
A. Braun, Abhandl. Berlin Akad. 1855: 44, pl. 3, figs. 27-31
(1855-holotype); Letcher et al., Mycol. Res. 110: 907 figs. 3A-D,
909 fig. 5 (2006).

Synonym:
Rhizophydium subangulosum (A. Braun) Rabenh.
Fl. Eur. Alg. 3: 281 (1868).

Description as for genus. Sporangium spherical when immature and spherical or angular at maturity, 10-35 micrometers diameter, with multiple discharge papillae.

GenBank LSU rDNA sequence AY439041, ITS1-5.8S-ITS2 rDNA sequence DQ485653.

Boothiomyces Letcher
Mycological Research 110: 911 (2006).
MycoBank no.: MB 29047
Description as for family. Sporangium spherical to angular, with either slightly raised or prominent, dome-shaped to conical, multiple discharge papillae. Zoospore contains a single lipid globule partially covered with a conspicuous fenestrated cisterna; KAS a spur terminated with a spherical or bifurcated knob.

Boothiomyces macroporosum (Karling) Letcher (Type)
Mycological Research 110: 911 (2006).
MycoBank no.: MB 334906

Basionym:
Rhizophydium macroporosum Karling
Sydowia 20: 76, plates XII, XIII, figs 9-20 (1967).

Description as for genus. Sporangium spherical on agar and angular on pollen and keratin, with multiple prominent, raised discharge papillae.

GenBank LSU rDNA sequence AY 439040, ITS1-5.8S-ITS2 rDNA sequence DQ485642.

 

Kappamycetaceae Letcher
Mycological Research 110: 912 (2006).
MycoBank no.: MB 82155
Sporangium epibiotic, spherical. Rhizoids thread-like, branched and compact. Resting spore epibiotic, spherical. Zoospore spherical, containing a ribosomal mass, a single lipid globule, a microbody, a nucleus, and a single mitochondrion, all enveloped in a double-membrane system; thick-membrane bounded vesicles, 0.2-0.3 micrometers in diameter, with electron-opaque contents, either surrounding the kinetosome and non-flagellated centriole or occurring in the peripheral cytoplasm; kinetosome and non-flagellated centriole parallel, or distal end of non-flagellated centriole slightly angled toward the kinetosome; the fibrillar bridge that connects the kinetosome and non-flagellated centriole is positioned diagonally between the two structures; both the kinetosome and non-flagellated centriole have an electron-opaque core.

Saprotrophic on pollen; primarily from terrestrial habitats.

Kappamyces is the type for the family.

Kappamyces Letcher and Powell
Nova Hedwigia 80: 125 (2005).
MycoBank no.: MB 28952
Description as for family.

Kappamyces laurelensis Letcher & M.J. Powell (Type)
Nova Hedwigia 80: 125 (2005).
MycoBank no.: MB 343251

Description as for genus. Sporangium spherical, 6-12 micrometers in diameter; zoospores discharge through a single large pore and often germinate in clusters when on agar.

GenBank LSU rDNA sequence AY439034, ITS1-5.8 S-ITS2 rDNA sequence DQ485666.

 

Alphamycetaceae Letcher
Mycological Research 112: 771 (2008).
MycoBank no.: MB 511771
Sporangium spherical with a single discharge pore. Rhizoids branched, delicate. Zoospore contains a single lipid globule partially covered with a conspicuous fenestrated cisterna; kinetosome and non-flagellated centriole are parallel and connected by a band of fibrillar material situated diagonally between the two structures; kinetosome-associated structure (KAS) is absent; microbody is simple; mitochondrion single, a portion of which is anterior to the kinetosome; moderately and uniformly electron-dense, thin-membraned vesicles occur in the cytoplasm adjacent to the kinetosome.

Saprotrophic on pollen; primarily from aquatic habitats.

Alphamyces is the type for the family.

Alphamyces Letcher
Mycological Research 112: 772 (2008).
MycoBank no.: MB 511785
Description as for family. Sporangium spherical with a single discharge pore, the upper two thirds of the sporangial wall covered with long slender branched or unbranched hairs up to 30-50 micrometers in length.

Alphamyces chaetiferum (Sparrow) Letcher (Type)
Mycological Research 112: 772 (2008).
MycoBank no.: MB 511786

Basionym:
Rhizophydium chaetiferum Sparrow,
Occ. Papers Boston Soc. Nat. Hist.: 8: 295 (1937).

Type: Sparrow, Papers Mich. Acad. Sci., Arts, Letters 1939: 24, pl. 2, figs 1-13 (1939-holotype).

Description as for genus. On agar, sporangium spherical, 15-22 micrometers in diameter; spores release through a single, wide apical to subapical discharge pore; upon discharge, zoospores usually germinate in clusters.

GenBank LSU rDNA sequence EF585606, ITS1-5.8S-ITS2 rDNA sequence EF585646.

 

Gorgonomycetaceae Letcher
Mycological Research 112: 767 (2008).
MycoBank no.: MB511768
Sporangium spherical with numerous elongate and sinuous discharge tubes. Rhizoids branched. Zoospore contains a single lipid globule partially covered with a conspicuous fenestrated cisterna; kinetosome and non-flagellated centriole are parallel and connected by fibrillar material with a zone of convergence approximately 0.010-0.025 micrometers in width centrally located between the two structures; kinetosome-associated structure (KAS) is absent; microbody is lobed; mitochondria one to five, with a portion anterior to the kinetosome.

Saprotrophic on pollen; primarily from aquatic habitats.

Gorgonomyces is the type for the family.

Gorgonomyces Letcher
Mycological Research 112: 767 (2008).
MycoBank no.: MB511769
Description as for family. Sporangium spherical with one or two broad discharge tubes when on an algal host, or up to 30 elongate discharge tubes when on artificial media.

Gorgonomyces haynaldii (Schaarschm.) Letcher (Type)
Mycological Research 112: 767 (2008).
MycoBank no.: MB 511770

Basionym:
Phlyctidium haynaldii Schaarschm.
Magyar No "ve'nytani Lapok. Kolozsva'r 1883: 58, pl 2, figs 1-11 (1883).

Synonym:
Rhizophydium haynaldii (Schaarschm.) A. Fisch.
Rabenh. Kryptogamen-Fl. 1: 92 (1892).

Type: Schaarschmidt, Magyar Novenytani Lapok. Kolozsvar (1883): 58, pl 2, figs 1-11 (1883- holotype); Letcher et al. 2008, Mycol. Res. 112: 764 figs 2E-I, 768 fig 5B (2008).

Description as for genus. Sporangium on agar is spherical, up to 50 micrometers in diameter at maturity. Rhizoidal system is sparingly branched with thread-like rhizoids arising from a cylindrical or knoblike extension of the sporangium base; at maturity, discharge tubes are numerous (10-30), elongate (30-45 micrometers), and sometimes bifurcated; on pollen, discharge tubes are generally short.

GenBank LSU rDNA sequence EF585605, ITS1-5.8S-ITS2 rDNA sequence EF585645.

 

Protrudomycetaceae Letcher
Mycological Research 112: 773 (2008).
MycoBank no.: MB 511772
Sporangium spherical to anatropous with one to three prominent discharge papillae. Rhizoids peg-like on algae or branched on agar. Zoospore contains a single lipid globule partially covered with a conspicuous fenestrated cisterna; kinetosome and non-flagellated centriole are parallel and connected by fibrillar material with a zone of convergence approximately 0.010-0.025 micrometers in width centrally located between the two structures; kinetosome-associated structure (KAS) absent; mitochondria are numerous; microbody is lobed around mitochondria proximal to the lipid globule.

Saprotrophic on pollen; primarily from aquatic habitats.

Protrudomyces is the type for the family.

Protrudomyces Letcher
Mycological Research 112: 773 (2008).
MycoBank no.: MB 511777
Description as for family.

Protrudomyces lateralis (Braun) Letcher (Type)
Mycological Research 112: 774 (2008).
MycoBank no.: MB 534024

Basionym:
Chytridium laterale A. Braun
Abhandl Berlin Akad.: 41 (1855).

Type:
A. Braun, Abhandl Berlin Akad. 1855: 44, pl. 2, figs 20-21, 23-26 (1855-holotype); Letcher et al., Mycol. Res. 112: 764 fig. 2R-U, 768 fig. 5E (2008).

Synonyms:
Rhizophydium laterale (A. Braun) Rabenh.
Fl. Eur. Alg. 3: 281 (1868).
Phlyctidium laterale (A. Braun) Sorok.
Arch. Bot. Nord France 2: 20 (1883).
Rhizophydium karlingii Sparrow
Aquatic Phycomycetes, 2nd edn: 243 (1960).

Description as for genus. On agar, sporangium is spherical to obpyriform, sometimes roundly triangular, 12-25 micrometers diameter, 15-25 micrometers in length, with 1-3 apical, subapical or lateral, blunt, protruding discharge papilla. Rhizoidal system is composed of 1-2 rhizoidal axes with branched rhizoids that are scarcely to moderately extensive.

Saprotrophic on pollen; primarily from aquatic habitats.

GenBank LSU rDNA sequence EF585628, ITS1-5.8S-ITS2 rDNA sequence EF585668.

 

Aquamycetaceae Letcher
Mycological Research 112: 774 (2008).
MycoBank no.: MB 511773
Sporangium spherical with few or many discharge pores. Rhizoids branched. Zoospore contains a single lipid globule partially covered with a conspicuous fenestrated cisterna; kinetosome and non-flagellated centriole are parallel and connected by fibrillar material with a zone of convergence approximately 0.075 micrometers in width centrally located between the two structures; kinetosome-associated structure (KAS) absent; a microtubular root is present; mitochondria single or few, with a portion anterior to the kinetosome; microbody lobed around a portion of a mitochondrion.

Saprotrophic on pollen; primarily from aquatic habitats.

Aquamyces is the type for the family.

Aquamyces Letcher 2008.
Mycological Research 112: 775 (2008).
MycoBank no.: MB 511778
Description as for family.

Aquamyces chlorogonii (Serbinow) Letcher (Type)
Mycological Research 112: 775 (2008).
MycoBank no.: MB 511784

Basionym:
Phlyctidium chlorogonii Serbinow
Scripta Bot. Horti Univ. Imper. Petro. 24: 156, plate 5, figs 11-17 (1907).

Synonym:
Rhizophydium chlorogonii (Serbinow) Jacz.
Opredelitel Gribov. Sovershennye Griby (Diploidnye Stadii). I. Fikomitsety: 38 (1931).

Type: Serbinow, Scripta Bot. Horti Univ. Imper. Petro. 1907: 24, pl. 5, figs 11-17 (1907-holotype); Letcher et al., Mycol. Res. 112: 765 figs. 3A-D, 769 fig. 5F (2008).

Description as for genus. Sporangium on agar is spherical, up to 35 micrometers diameter, with up to ten raised, dome-shaped discharge papillae, and zoospores emerged singly through the discharge pores. Rhizoidal system most commonly is composed of short, robust, sometimes bifurcate rhizoidal axes from which rhizoids branch; at maturity rhizoids are strongly branched but compact; on pollen, sporangia are angular and the discharge papillae more prominent than when on agar.

GenBank LSU rDNA sequence EF585603, ITS1-5.8S-ITS2 rDNA sequence EF585643.

 

Angulomycetaceae Letcher
Mycological Research 112: 775 (2008).
MycoBank no.: MB 511774
Sporangium spherical with few to numerous discharge papillae. Rhizoids branched, extensive, and compact. Zoospore contains several small mitochondria; a single lipid globule partially covered with a simple cisterna; kinetosome and non-flagellated centriole are parallel and connected by fibrillar material with a zone of convergence approximately 0.01-0.025 micrometers in width centrally located between the two structures; kinetosome-associated structure (KAS) is absent; microbody is lobed with a portion anterior to the kinetosome; vesicles with morphologically distinct matrices in the cytoplasm peripheral to the ribosomal core, but not in the vicinity of the kinetosome.

Saprotrophic on pollen; primarily from aquatic habitats.

Angulomyces is the type for the family.

Angulomyces Letcher 2008.
Mycological Research 112: 776 (2008).
MycoBank no.: MB 511779
Description as for family.

Angulomyces argentinensis Letcher
Mycological Research 112: 776, figs. 3I-L, 5G (2008).
MycoBank no.: MB 511787

Description as for genus. On agar, sporangium is spherical to angular, up to 35 micrometers diameter, with numerous raised discharge papillae; on pollen, sporangia are angular and discharge papillae more prominent then when on agar.

GenBank LSU rDNA sequence EF585595, ITS1-5.8S-ITS2 rDNA sequence EF585635.

 

Globomycetaceae Letcher
Mycological Research 112: 776 (2008).
MycoBank no.: MB 511775
Sporangium spherical with a single discharge pore. Rhizoids sparingly branched. Zoospore with a single lipid globule partially covered with a conspicuous or inconspicuous fenestrated cisterna; kinetosome and non-flagellated centriole are parallel and connected by fibrillar material with a zone of convergence approximately 0.075 micrometers in width centrally located between the two structures; kinetosome-associated structure (KAS) is absent; microbody is simple or lobed; distinct thick-membraned spherical vesicles with uniformly electron-dense contents occur in the peripheral cytoplasm.

Saprotrophic on pollen; primarily from aquatic habitats.

Globomycetaceae contains two genera, Globomyces and Urceomyces. Globomyces is the type for the family.


Globomyces Letcher 2008.
Mycological Research 112: 777 (2008).
MycoBank no.: MB 511780
Description as for family. Zoospore contains a single lipid globule partially covered with conspicuous fenestrated cisterna; microbody is lobed.

Type: Globomyces pollinis-pini (A. Braun) Letcher (Type)
Mycological Research 112: 777, figs. 3Q-T, 5H1 (2008).
MycoBank no.: MB 511788

Basionym:
Chytridium pollinis-pini A. Braun
Abhandl. Berlin Akad.: 40 (1855).

Synonyms:
Chytridium vagans A. Braun
Monatsber. Berlin Akad.: 588 (1856).
Phlyctidium vagans (A. Braun) Rabenh.
Fl. Eur. Alg. 3: 278 (1868).
Rhizophydium pollinis-pini (A. Braun) Zopf
Abhandl. Naturforsch. Gesell. Halle: 17 (1887).

Type: A. Braun, Abhandl.. Berlin Akad. 1855: 40, pl. 3, figs. 1-15 (1855-holotype); Letcher et al., Mycol.Res. 112: 765 figs. 3Q-T, 770 fig. 5H-1 (2008)

Description as for genus. On agar, sporangium is spherical, up to 25 micrometers diameter, with a single broad apical or lateral papilla, which becomes evident a few minutes before zoospore release; on pollen, sporangia are sessile or pedicellate and spherical or urceolate when empty; Zoospore 3-4 micrometers in diameter emerge in an evanescent vesicle, and the sporangial wall at the edge of the discharge pore is recurved after discharge.

GenBank LSU rDNA sequence EF585625, ITS1-5.8S-ITS2 rDNA sequence EF585665.

Urceomyces Letcher
Mycological Research 112: 777 (2008).
MycoBank no.: MB 511781
Sporangium spherical with a single discharge pore. Zoospore contains a single lipid globule partially covered with an inconspicuous fenestrated cisterna; microbody is simple.

Urceomyces sphaerocarpum (Zopf) Letcher (Type)
Mycological Research 112: 778 (2008, figs. 4A-D, 5H2 (2008).
MycoBank no.: MB 511789

Basionym:
Rhizidium sphaerocarpum Zopf
Nova Acta Acad. Leop.-Carol. 47:202 (1884).

Synonym:
Rhizophydium sphaerocarpum (Zopf) A. Fisch.
Rabenh. Kryptogamen-Fl. 1: 95 (1892).

Type: Zopf, Nova Acta Acad. Leop.-Carol. 47: 202, pl 19, figs. 16-27 (1884-holotype); Letcher et al., Mycol. Res. 112: 778, figs. 4A-D, 5H2 (2008)

Description as for genus. On agar, sporangium is spherical, up to 25 micrometers in diameter, with a single broad apical or lateral papilla, which becomes evident a few minutes before zoospore release; on pollen, sporangia are sessile or pedicellate and spherical or urceolate when empty; Zoospores 3-4 micrometers in diameter emerge in an evanescent vesicle, and the sporangial wall at the edge of the discharge pore is recurved after discharge. Rhizoids are isodiametric, sparsely branched, and develop from a slender, delicate main axis. Resting spores form on pollen but not in agar cultures; resting spores are spherical, 12-18 micrometers in diameter, with a smooth colourless wall and contained a single large lipid globule; the wall becomes rugose and light brown in age.

GenBank LSU rDNA sequence EF585619, ITS1-5.8S-ITS2 rDNA sequence EF585659.

 

Pateramycetaceae Letcher
Mycological Research 112: 778 (2008).
MycoBank no.: MB 511776
Sporangium spherical with a single discharge pore. Rhizoidal system consists of a rhizoidal axis and extensive, branched, isodiametric rhizoids. Zoospore contains a single lipid globule partially covered with a fenestrated cisterna; kinetosome and non-flagellated centriole are parallel and connected by fibrillar material with a zone of convergence approximately 0.010 to 0.025 micrometers in width centrally located between the two structures; kinetosome-associated structure (KAS) is absent; mitochondrion single, a lobe of which lies above and proximal to the kinetosome; microbody lobed; walled, moderately electron-dense vesicles occur in the peripheral cytoplasm, often proximal and lateral to the kinetosome.

Saprotrophic on pollen; primarily from aquatic habitats.

Pateramyces is the type for the family.


Pateramyces
Letcher
Mycological Research 112: 779 (2008).
MycoBank no.: MB511782
Description as for family.

Pateramyces corrientinensis Letcher (Type)
Mycological Research 112: 779, figs. 4E-H, 5I (2008).
MycoBank No.: MB511790

Description as for genus. On agar, sporangium is spherical, up to 30 micrometers in diameter, with a single broad apical or subapical papilla; Zoospores are spherical, 3-4 micrometers in diameter, and emerge from the sporangium in a vesicle through a discharge pore formed by the dehiscence of a circular operculum; the operculum is completely separated and pushed away from the sporangium by the expanding discharge vesicle.

Saprotrophic on pollen; primarily from aquatic habitats.

GenBank LSU rDNA sequence EF585617, ITS1-5.8S-ITS2 rDNA sequence EF585657.

 

Family incertae sedis

Coralloidiomyces Letcher
Mycologia 100: 328 (2008).
MycoBank no.: MB 506748
Sporangium sessile or occasionally interbiotic. Rhizoidal system is an isodiametric rhizoidal axis and sparsely branched, thin rhizoids. Resting spores are spherical, hyaline, with a thick, smooth wall and contain one to several large lipid globules. Zoospore with a single lipid globule partially covered with a conspicuous fenestrated cisterna; a microbody with laminated lobes that extend into and partially around the ribosomal core; a KAS as a solid shield, from which a microtubular root composed of four microtubules extends to the fenestrated cisterna; kinetosome and non-flagellated centriole are parallel and connected by fibrillar material with a zone of convergence approximately 0.075 micrometers in width centrally located between the two structures.
Saprotrophic on pollen; primarily from aquatic habitats.

Coralloidiomyces digitatusLetcher (Type)
Mycologia 100: 330, figs. 2A-Q, 3A-D, 5A-F (2008).
MycoBank no.: MB 506749

Description as for genus. Sporangium in pure culture on nutrient agar sporangium lobed at maturity, 20-40 micrometers in diameter with multiple discharge papillae; zoospores are discharged from one or more inoperculate discharge papillae. Resting spore spherical, 12-20 micrometers in diameter, with one to several large lipid globules.

GenBank LSU rDNA sequence EF634248, ITS1-5.8S-ITS2 rDNA sequence EF634250.

 

Batrachochytrium Longcore, Pessier and Nichols (Type)
Mycologia 91: 220 (1999).
MycoBank no.: MB 27960
Thalli monocentric or colonial; each segment of colonial thallus forms a sporangium. Sporangium with 1 or more inoperculate discharge papillae. Rhizoidal system composed of 1-several rhizoidal axes with thread-like rhizoids. Zoospore spherical or slightly ovate, with aggregated ribosomes; numerous lipid globules associated with a sheet of microbody and nested in peripheral cytoplasm; microtubular root a group of microtubules extending parallel to the kinetosome into the ribosomal aggregation; kinetosome and non-flagellated centriole connected by overlapping fibrils; fenestrated MLC cisterna and transition zone plug absent.
Forming sporangia in epidermis of amphibians.

Batrachochytrium dendrobatidis Longcore, Pessier and Nichols (Type)
Mycologia 91: 220, figs. 2-30 (1999).
MycoBank no.: MB 450228

Description as for genus. Sporangia on agar up to 40 micrometers in diameter.

GenBank LSU rDNA sequence AY546693, ITS1-5.8S-ITS2 rDNA sequence AY997031.

 

Entophlyctis helioformis (P.A. Dang.) Ramsbottom
Transactions of the British Mycological Society 5: 318 (1915)
MycoBank no.: MB 100289

Basionym:
Chytridium helioformis P.A. Dang.
Bull. Soc. Bot. France 33: 356 (1886); Ann. Sci. Nat. Bot. VII, 4: 293 (1886).

Synonyms:
Chytridium heliomorphum P.A. Dang.
Journ. De Botanique 2: 143, pl. 5, figs. 19-23 (1888).
Entophlyctis heliomorpha (P.A. Dang.) A. Fisch.
Rabenhorst. Kryptogamen-Fl. 1: 118 (1892).

Sporangium spherical or ovoid, 6-20 micrometers in diameter, wall smooth, colorless, somewhat thickened, discharge tube cylindrical, of variable length. Rhizoids unbranched or sparingly branched, arising from 3-12c main axes formed at any place on the sporangium. Resting spore borne like the sporangium, spherical, subspherical, or broadly ovoid, 8-24 micrometers in diameter, with a double wall, the outer thicker than the inner, contents yellowish, with numerous oil globules; germination not observed. Zoospores spherical, 3-4 micrometers in diameter, with a conspicuous centric or eccentric colorless globule and a long flagellum; escaping individually upon the rupture of the tip of the discharge tube, movement swimming with axial rotation, or amoeboid.

Saprotrophic in Nitella, Vaucheria, and Chara spp.

GenBank LSU rDNA sequence DQ273784, ITS1-5.8S-ITS2 rDNA sequence AY997048.

Rhizophlyctis harderi Uebelmesser
Archiv fur Mikrobiologie 25: 324, fig. 7 (1956).
MycoBank no.: MB 305151
Sporangium spherical, smooth-walled, 40-60 micrometers in diameter. Rhizoids arising from one to several places on the sporangium, delicate, branched, those within the substrate with a small apophysis. Resting spore with a smooth, thick wall and large eccentric refractive globule, bearing a number of elongate ornamentations. Zoospores spherical, 4 micrometers in diameter, with a 20 micrometer long flagellum and small, colorless basal globule, discharged through a 40 micrometer broad opening in a mass surrounded for a time by the gelatinized wall of the sporangium. Zoospore contains a nucleus is partially embedded in the ribosomal aggregation; multiple lipid globules, the posterior lipid globule encased by a fenestrated cisterna, the anterior globules encased by simple cisternae; two microtubular roots, one of which originates at the side of the kinetosome and extends toward the fenestrated cisterna, the other originating near the anterior ends of the kinetosome and non-flagellated centriole and extending anteriorly into the cytoplasm.

Saprotrophic on pine pollen, from halophytic soils and in fresh-water deposits.

GenBank LSU rDNA sequence EF585617, ITS1-5.8S-ITS2 rDNA sequence EF585657.


Rhizophydium aestuarii
(Ulken) Amon
Mycologia 76: 138, fig. 13 (1984).
MycoBank no.: MB 319900

Basionym:
Phlyctochytrium aestuarii Ulken
Veroff. Inst. Meeresforsch. Bremerhaven 13: 215, figs. 5, 6 (1972).
Sporangium spherical or subspherical, 23-40 micrometers in diameter, with numerous (5-16) protruding discharge papillae. Rhizoids thin, up to 70 micrometers in length, with an apophysis. Resting spore sessile, spherical, 13-21 micrometers in diameter, contents a globule 9-15 micrometers in diameter; germination of resting spore not observed. Zoospore spherical or oval, 3-4 micrometers in diameter, with a flagellum 13-17 micrometers in length; zoospore contains an aggregation of ribosomes, a single lipid globule partially covered with a fenestrated cisterna and a microbody, a microtubular root composed of 7 parallel microtubules, and a fibrillar bridge between the kinetosome and non-flagellated centriole. Mass culture yellow.

GenBank LSU rDNA sequence DQ485541, ITS1-5.8S-ITS2 rDNA sequence DQ485605.
Saprobic on pollen, from submersed estuary soil.


Rhizophydium littoreum
Amon
Mycologia 76: 137, figs. 1-12 (1984).
MB 107228
Sporangium spherical or subspherical, 13-26 micrometers in diameter when on Bryopsis, with 1-(1-2) papillae, 80-120 micrometers in diameter when on nutrient agar, with 1-10 papillae. Rhizoid system on agar moderately branched, often lacking apophysis and extending about 1.5 times diameter of sporangium. Zoospore spherical to ovoid, about 2.7-3.6 micrometers in diameter, phototactic, flagellum about 24 micrometers in length; zoospores contain an aggregation of  ribosomes, a single lipid globule partially covered with a fenestrated cisterna and a microbody, a microtubular root, and a fibrillar bridge between the kinetosome and non-flagellated centriole. Mass culture pale yellow. 
An obligate halophyte on siphonaceous alga Bryopsis plumosa and Codium sp.

Type isolate for the species, ATCC 36100.

GenBank LSU rDNA sequence DQ485540, ITS1-5.8S-ITS2 rDNA sequence DQ485604.






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