Pyrenophora phaeocomes (Rebent.) Fr., Summa veg. Scand., Section Post. (Stockholm): 397 (1849) MycoBank: MB 222199

= Sphaeria phaeocomes Rebent., Prodr. fl. neomarch. (Berolini): 338 (1804)

Figures of Pyrenophora phaeocomes (neotype). A, B. Ascomata on host specimen. C. Close up of ascoma. D. Side view of ascoma with neck covered with setae. E, F. Sections of ascomata. G. Section of peridium. H. Ostiole, with central periphyses. J. Light brown seta. K-M. Asci with 8 ascospores, distinct ocular chamber and apical ring. N-Q. Mature and immature muriform ascospores. Scale bars: E-F=200 μm, G=30 μm, H=80 μm, J=50 μm, K-M=50 μm, N-Q=15 μm.

Plate 1

 

Description (from neotype)

Sexual state: Ascomata 380–450 × 370–430 μm ( = 395 × 380 µm, n = 10), solitary or scattered, initially immersed, becoming erumpent to near superficial, globose to subglobose, broadly or narrowly conical, coriaceous, smooth-walled, ostiolate. Ostiole usually broadly papillate, central ostiolar canal filled with periphyses and covered with setae. Setae brown to reddish-brown, darkened at the base, septate and tapered towards the apex. Peridium 40–70 μm ( = 45 µm, n = 20) wide, comprising two types of cells, outer cells of 1–2 layers of heavily pigmented cells of textura angularis, inner layer composed of small, light brown to hyaline cells of textura angularis. Pseudoparaphyses not observed. Asci 300–400 × 130–160 μm ( = 345 × 140 µm, n = 20), 8-spored, bitunicate, fissitunicate, clavate to sub-cylindrical, with a short, broad pedicel, thickened and rounded at apex with a distinct ocular chamber surrounded by a large, distinct, apical ring. Ascospores 78–96 × 27–34 μm ( = 88 × 30 µm, n = 40), biseriate to overlapping triseriate, ellipsoidal with broadly rounded ends, hyaline to light brown when immature, becoming brown to chestnut brown when mature, muriform with 5–6 transverse septa and single longitudinal septa in one or all cells, constricted at the septa, smooth-walled, relatively thick-walled, with a 5–9 μm thick mucilaginous sheath. Asexual state: not observed, but see notes.

Material examined: SWEDEN, on leaves of Anthoxanthum (Poaceae), 7 August 1951, J. Nannfeldt (UPS 170980, neotype).

Distribution: Putative collections of Pyrenophora phaeocomes have reported from Belgium, Czech Republic, Denmark, Norway, Portugal, Sweden (GBIF, 2014), but these identifications have not been confirmed  by molecular data.

Type specimen: UPS (neotype), Putative collections of Pyrenophora phaeocomes are available in BG, BPI, C and O

 Sequence data: There is no extype sequence data.

Molecular data is available in GenBank for a putative strain of Pyrenophora phaeocomes (DAOM 222769). However it is not clear if this species was correctly identified and it does not appear to be illustrated anywhere. DAOM 222769 was used by the Assembling the Fungal Tree of Life (AFTOL) project in 2007. AFTOL ID: AFTOL: 283

 ITS: JN943649.1 (ITS1/ITS4); LSU: JN940093.1 (LROR/LR5); SSU: JN940960.1 (NS1/NS4); EF1a: DQ497607.1 (983/2218R); RPB2: DQ497614.1 (fRPB2-SF/fRPB2-7cR)

 Notes: Pyrenophora phaeocomes is the type species of Pyrenophora. Sivanesan (1987) stated that P. phaeocomes has a Drechslera asexual state, but the species was not identified. In our study we did not observe the asexual state of Pyrenophora phaeocomes on the neotype.

 Importance and role

As Pyrenophora phaeocomes is a saprobe on leaves of Anthoxanthum (Poaceae) it plays a vital role in ecosystems in recycling nutrients. A putative collection of Pyrenophora phaeocomes was recorded on Vitis species (Farr and Rossman 2011), but the affected plant parts were not recorded.

 Biosecurity: Generally, Pyrenophora phaeocomes is associated with foliage and causes leaf spots (Farr et al. 1989). Therefore, foliage free dormant cuttings do not provide a pathway for this fungus. Therefore quarantine assessment is probably not required unless it proves to be an endophyte.

Biochemistry

There appears to be no known biochemical studies on Pyrenophora phaeocomes. This species should be assessed for its chemical diversity and novel compounds.

 

References

Farr DF, Bills GF, Chamuris GP, Rossman AY (1989) Fungi on Plants and Plant Products in the United States. APS Press, St. Paul, Minnesota USA.

Farr DF, Rossman AY (2011) Fungal Database, Systematic Mycology and Microbiology Laboratory, ARS, USDA. http://nt.ars grin.gov/fungaldatabases/fungushost/fungushost.cfm Accessed January 2014.

Fries EM. 1849 – Summa vegetabilium Scandinaviae.Typographia Academica, Uppsala

GBIF, 2014 (http://data.gbif.org/species/2616544/)

Rebentisch JF. 1804 – Prodromus Flora Neomarchicae. Schüppel, Berlin

Sivanesan A. 1987 – Graminicolous species of Bipolaris, Curvularia, Drechslera, Exserohilum and their teleomorphs. Mycological Papers 158, 1–261 

Contributors:

Ariyawansa HA1,2,3, Kang JC1, Alias SA4, Chukeatirote E2,3and Hyde KD2,3,5,6
1The Engineering and Research Center for Southwest Bio-Pharmaceutical Resources of National Education Ministry of China, Guizhou University, Guiyang 550025, Guizhou Province, China
2School of Science, Mae Fah Luang University, Chiang Rai. 57100, Thailand
3Institute of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand
4Institute of Biological Sciences, University of Malaya, 50603, Kuala Lumpur
5Centre for Mountain Ecosystem Studies (CMES), Kunming Institute of Botany, 8Chinese Academy of Science, Kunming 650201, Yunnan, China
6World Agroforestry Centre, East Asia Office, Kunming 650201, Yunnan, China