Pseudocercospora microsori - Fungal Planet

156 Persoonia – Volume 25, 2010 

Pseudocercospora microsori

Persoonial Reflections 

157 

Fungal Planet 68 – 23 December 2010 

Pseudocercospora microsori R.G. Shivas, A.J. Young & B.C. McNeil, sp. nov. 

Frondium maculae amphigenae, sparsae ad confluentes, saepe tegentes 

multum paginae frondium, circulares ad irregulares, marginibus distinctis, 

inaequalibus et areis chloroticis, finitis venis principibus, 5–15 mm diametro, 

fuscis rubellis-brunneis, centris cinerascentibus. Conidiomata rubella-brunnea, 

amphigena, fasciculata, orientia ex stromate maturo substomatali 20–60 

µm lato. Conidiophora 5–30 in fasciculis densis vel laxis, geniculata ad sinuosa, 

inramosa, rubella-brunnea, pallidiora ad apicem, 1–5-septata 30–65 

× 3–5 µm. Cellulae conidiogenae terminales in conidiophoro, integratae, 

subcylindraceae, brunneolae, leves, 10–35 × 2.5–4 µm. Conidia obclavata 

ad subcylindracea, curvata ad flexuosa, apice rotundato, basi truncata vel 

paulum obconice truncata, 2–12-septata, 50–110 × 2.5–4 µm, brunneola, 

levia; hila nec crassata nec fuscata. 

Etymology. From the name of the host plant Microsorum (Polypodiaceae). 

Frond spots amphigenous, scattered to confluent, often covering 

much of the frond surface, circular to irregular with distinct, 

uneven margins and chlorotic haloes, limited by the main veins, 

5–15 mm diam, dark reddish brown with centres becoming grey. 

Conidiomata reddish brown, amphigenous, fasciculate, arise 

from a well-developed substomatal stroma, 20–60 µm wide. 

Conidiophores 5–30 in dense or loose fascicles, geniculate 

to sinuous, unbranched, reddish brown, paler towards apex, 

1–5-septate 30–65 × 3–5 µm. Conidiogenous cells terminal on 

conidiophore, integrated, subcylindrical, pale brown, smooth, 

10–35 × 2.5–4 µm. Conidia obclavate to subcylindrical, curved 

to flexuous, apex rounded, base truncate to slightly obconically 

truncate, 2–12-septate, 50–110 × 2.5–4 µm, pale brown, 

smooth; hila not thickened nor darkened. 

Typus. Australia, Queensland, Brisbane, West End, Doris Street, on 

fronds of Microsorum pustulatum, 6 Aug. 2010, B.C. McNeil, BRIP 53617, 

holotype; cultures ex-type BRIP 53617, ITS sequence GenBank HQ624985, 

MycoBank MB517678; Indooroopilly Research Centre, Indooroopilly, 26 Aug. 

2010, B.C. McNeil, BRIP 53618, paratype. 

Notes — Although several Pseudocercospora spp. have 

been recorded on ferns, P. microsori is the first on the genus 

Microsorum. Other Pseudocercospora spp. with fasciculate 

conidiophores that have been recorded on ferns include: 

P. adianti 1 , P. arachniodis 2 , P. athyrii 2 , P. christellae 3 , P. cyatheae 

4 , P. lonchitidis 1 , P. nephrolepidis 5 , P. phyllitidis 1 , P. plagiogyriae 

2 , P. pteridicola 6 , P. pteridophytophila 2 and P. thelypteridis 2 . 

Pseudocercospora microsori is morphologically distinct from 

these species with its combination of moderately wide (2.5–4 

µm) and curved to flexuous conidia. A megablast search of 

NCBIs GenBank nucleotide database using the ITS sequence 

revealed high identity to P. lythri (GenBank EF535713; Identities 

= 496/498 (99 %), Gaps = 0/498 (0 %)), P. humuli (GenBank 

EF535685; Identities = 495/498 (99 %), Gaps = 1/498 (0 %)), 

P. crousii (GenBank GQ852756; Identities = 497/502 (99 %), 

Gaps = 2/502 (0 %)) and P. araliae (GenBank EF535717; Identities 

= 495/499 (99 %), Gaps = 1/499 (0 %)). Genomic DNA of 

P. microsori (holotype) is stored in the Australian Biosecurity 

Bank (www.padil.gov.au/pbt/). 

96 

Pseudocercospora humuli humuli voucher voucher KACC 42529 KACC (EF535685) 42529 (EF535685) 

68 

Pseudocercospora microsori microsori BRIP 53617 BRIP ( ) 53617 (HQ624985) 

56 

Pseudocercospora balsaminae balsaminae voucher voucher KACC 42643 KACC (EF535715) 42643 (EF535715) 

53 

Pseudocercospora lythri lythri voucher voucher KACC 42641 KACC (EF535713) 42461 (EF535713) 

95 

Pseudocercospora araliae araliae voucher voucher KACC 42645 KACC (EF535717) 42645 (EF535717) 

Pseudocercospora kaki CPC kaki 10636 CPC 10636 (GU214677) (GU214677) 

Pseudocercospora mangifericola mangifericola BRIP 52776 BRIP (GU188048) 52776 (GU188048) 

Pseudocercospora avicenniae avicenniae BRIP 52764 BRIP (GU188047) 52764 (GU188047) 

Cercospora zebrinae CBS CBS 118790 118790 (GU214657) (GU214657) 

0.005 

Maximum Likelihood Tree obtained using the General Time 

Reversible Model from an ITS sequence alignment generated 

with MUSCLE in MEGA4. The bootstrap support values from 

1 000 replicates are shown at the nodes. Bar represents number 

of substitutions per site. The species described here is printed 

in bold face. The tree was rooted to Cercospora zebrinae CBS 

118790 (GU214657). 

Colour illustrations. Microsorum pustulatum in a garden, Brisbane with a 

frond (right) severely infected with P. microsori; frond with lesions caused by 

P. microsori; stroma with conidiophores; conidia. Scale bars (left to right) = 

1 cm, 10 µm, 10 µm. 

References. 1 Crous PW, Braun U. 2003. Mycosphaerella and its anamorphs: 

1. Names published in Cercospora and Passalora. CBS Biodiversity 

Series 1: 1–571. 2 Guo YL, Liu XL, Hsieh WH. 1998. Pseudocercospora. 

Flora Fungorum Sinicorum, Vol. 9. Science Press, Beijing. 3 Phengsintham P, 

Chukeatirote E, McKenzie EHC, Moslem MA, Hyde KD, Braun U. 2010. Two 

new species and a new record of cercosporoids from Thailand. Mycosphere 

1: 205–212. 4 Nakashima C, Inaba S, Park JY, Ogawa Y. 2006. Addition and 

re-examination of Japanese species belonging to the genus Cercospora and 

allied genera. IX. Newly recorded species from Japan (4). Mycoscience 47: 

48–52. 5 Kirschner R, Chen CJ. 2007. Foliicolous hyphomycetes from Taiwan. 

Fungal Diversity 26: 219–239. 6 Braun U, Melnik VA. 1997. Cercosporoid fungi 

from Russia and adjacent countries. Proceedings of the Komarov Botanical 

Institute, Russian Academy of Sciences. 

Roger G. Shivas, Anthony J. Young & Bradley C. McNeil, Agri-Science Queensland, Ecosciences Precinct, Dutton Park 4102, Queensland, Australia; 

e-mail: roger.shivas@deedi.qld.gov.au, anthony.young@deedi.qld.gov.au & brad.mcneil@deedi.qld.gov.au 

© 2010 Nationaal Herbarium Nederland & Centraalbureau voor Schimmelcultures

Pseudocercospora microsori - Fungal Planet

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