Botanical Studies (2008) 49: 277-280

*

Corresponding author: Present address: Wenshan Branch,

Taiwan Tea Experiment Station, COA, EY Taipei 22391,

Taiwan; E-mail: amyloplast1982@yahoo.com.tw;

r93633005@ntu.edu.tw.

INTRODUCTION

The genus Muribasidiospora Kamate & Rajendren was

first established in 1968 (Rajendren, 1968) and belongs

to Basidiomycota, Ustilaginomycetes, Exobasidiales,

Exobasidiaceae (Kirk et al., 2001). All members in the

genus are phytoparasites, and only three species¡XM.

hesperidium (Maire) Kamat & Rajendren, M. indica

Kamat & Rajendren, and M. celtidis (Ramakrishnan,

T. S. & K.) Kamat & Rajendren¡Xhave been recorded

(Rajendren, 1968). Their respective hosts are Celtis

tetrandra (Ulmaceae) infected by M. celtidia, Rhus

mysorensis (Anacardiaceae) by M. indica, and R .

oxyacantha by M. hesperidum (Rajendren, 1968; Donk,

1974; Crous et al., 2003). Muribasidiospora hesperidium

and M. celtidis originally belonged to Exobasidium viz.

E. hesperidium Maire and E. celtidis Ramakrishnan

T. S. & K, but Rajendren revised the two species as

Muribasidiospora owing to their production of muriform

basidiospores (Rajendren, 1968). The taxonomy of

Muribasidiospora and Exobasidium are similar, but the

differences are that Muribasidiospora bears muriform

basidiospores, 2-4 sterigmata, sterile hyphidia-like

hyphal elements between the basidia and basidia with

thickened cell walls at the base (Begerow et al., 2001).

The other characteristics are sporulation by rupturing

epidermal cells, basidiospore germination by budding to

produce cylindrical conidia, and the formation of yeast-

like colonies (Begerow et al., 2001). Phylogenetically,

Muribasidiospora is closely related to Exobasidium, based

on the 5¡¦ region of nuclear large subunit of rDNA (LSU

rDNA) (Begerow et al., 2001 and 2002).

A red leaf spot disease of Gordonia axillaris (Roxb.)

Dietr. was discovered in May, 2006 in Taiwan. Gordonia

axillaris, which belongs to Theaceae is distributed from

100 m to 2,200 m above sea level in Taiwan. Gordonia

axillaris is native to Taiwan, and some people plant

them as ornamentals. The new disease was collected in

Anmashan, located 2,000 m above sea level, and the

weather is usually humid and cool. Owing to its different

hosts and morphology, the pathogen was identified as

a new species, which was named Muribasidiospora

gordoniae Shih, Hsieh et Fu. Up to now, no

Muribasidiospora diseases have been recorded in Taiwan,

and the new species on G. axillaris will be described. On

the other hand, the ITS sequence of M. gordoniae is also

analyzed in this article.

MATERIALS AND METHODS

The specimen was collected in Anmashan, Taichung,

Taiwan on 5 May 2006. Hymenium were scraped and

stained with lactophenol containing 0.05% cotton blue.

Cross sections of the infected tissue were made by hand to

observe the hymenium on infected cells. The germination

Muribasidiospora gordoniae sp. nov. occurring on

Gordonia axillaris in Taiwan

Huann Ju HSIEH

1

, Chuen Hsu FU

2

, and Hsin Hui SHIH

1,

*

1

Department of Plant Pathology and Microbiology, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei

10617, Taiwan

2

Division of Forest Protection, Taiwan Forestry Research Institute, 6 Floor, Room 610, #67 San-Yuan Street, Zhongzheng

District, Taipei 10079, Taiwan

(Received March 5, 2007; Accepted November 20, 2007)

ABSTRACT.

The genus Muribasidiospora producing muriform basidiospores belongs to Exobasidiaceae.

Three species, Muribasidiospora hesperidium, M. indica and M. celtidis, have been recorded.

Muribasidiospora gordoniae, which causes a prominant red leaf spot disease on Gordonia axillaris, is a new

species in Taiwan based on the host and its morphology. Additionally, analysis of the internal transcribed

region (ITS1-5.8S rDNA¡VITS2) reveals M. gordoniae is closely related to the genus Exobasidium, especially

those species of it occurring on Camellia species.

Keywords: Exobasidiaceae; Gordonia axillaris; Internal transcribed spacer; Muribasidiospora disease;

Taiwan; Taxonomy.

MICROBIOLOGY

278

Botanical Studies, Vol. 49, 2008

of basidiospores was performed on water agar. The fresh

tissue was attached to the lid of the petri dish to allow

basidiospores to fall on to the agar, and the germinated

basidiospores were then transfered to a potato sucrose

agar (PSA) medium. All isolates were grown at 22¢XC.

Half of the dried herbarium material was deposited at

the Department of Plant Pathology and Microbiology,

National Taiwan University (NTUPPM), and half went to

the herbarium at the National Museum of Natural Science,

Taiwan (TNM). The living culture was deposited in the

Bioresource Collection and Research Center (BCRC).

Genomic D NA was extracted with a VIOGENE Plant

Genomic DNA Mini System. The internal transcribed

spacer (ITS) region, composed of ITS1, 5.8S rDNA

and ITS2, was amplified with primer pairs, ITS1

(5¡¦-TCCGTAGGTGAACCTGCGG-3¡¦) and ITS4 (5¡¦-

TCCTCCGCTTATTGATATGC-3¡¦). The PCR product was

purified using a VIOGENE PCR-M Clean Up System.

The purified rDNA was then sequenced with the ITS1 and

ITS4 primers. The obtained ITS sequence was blasted in

the NCBI database (National Center for Biotechnology

Information).

RESULT

Muribasidiospora gordoniae Shih, Hsieh et Fu, sp. nov.

(Figure 1A-I)

Etymology. Named after the host plant, Gordonia

axillaris (Roxb.) Dietr.

Figure 1. Muribasidiospora gordoniae sp. nov. occurring on Gordonia axillaris. A-B, symptoms; C-D: basidia bearing 2-3 sterigmata;

E: colonies on PS A at 22¢XC after 47 days growth; F: germination of basidiospores; G-I: draw-line of hymenium; G: basidia; H:

basidiospores; I: germination of basidiospores. Bar: C-D, F & G-I = 10 £gm; E = 5 mm.

HSIEH et al. ¡X

Muribasidiospora gordoniae

, a new species in Taiwan

279

Hymenium hypophyllum. Basidia hyalina, cylindrica,

120-170 ¡Ñ 5-7 £gm, terminaliter cum 2-3 sterigmatibus

subulatis, 3-4 ¡Ñ (1-)2-2.5 £gm. Basidiosporae primo

continuis dein muriform septatis, 15-21 ¡Ñ 5.5-7 £gm.

Conidia hyalina, 4-11 ¡Ñ 0.6-1.5 £gm.

Holotype. TAIWAN. Taichung: Anmashan, in folia on

Gordonia axillaris (Roxb.) Dietr. 5 May 2006, H.-H. Shih,

TNM F0020737 (NTUPPM-623), BCRC34277 (living

culture).

Fungi infecting lower young leaves and forming red

leaf spots. Leaf spots conspicuous, red, irregular, slightly

hypertrophic; abaxial lesion surface covered with thick,

protruding, white and powdery hymenium, making the leaf

slightly curled.

Hymenium composed of basidia, basidiospores and

conidia. Basidia rupturing from epidermis, cylindrical,

fewer thickened at the basal basidia, 120-170 ¡Ñ 5-7 £gm,

with 2-3 sterigmata. Sterigmata subulate, 3-4 ¡Ñ (1-)2-2.5

£gm. Basidiospores broad obovoid, muriform septa,

15-21 ¡Ñ 5.5-7 £gm. Conidia short fusiform to filiform,

bacilliform, 4-11 ¡Ñ 0.6-1.5 £gm. Basidiospores on water

agar germinating to produce short bacilliform conidia in

the periphery by budding without germ tubes. Colonies on

PSA yeast-like, sticky, smooth, pale yellow at the surface

of the culture, about 1 cm at 22¢XC after 47 days growth,

consisting of abundant budding secondary spores. The

optimal growth temperature is 20-25¢XC.

The ITS sequence (accession number in NCBI

database: EU262600) of

Muribasidiospora gordoniae is

composed of 598 bases. A BLAST search in the NCBI

database revealed that the ITS sequence of M. gordoniae

to be closely related to the Exobasidium genus, especially

to those species occurring on Camellia species such as

E. reticulatum (AB180377, 92% identity) and E. gracile

(AB180371, 88% identity). Up to now, ITS sequences

o f Muribasidiospora species are absent from the NCBI

database, and that of M. gordoniae is the first one.

DISCUSSION

The morphology of Muribasidiospora is similar

t o Exobasidium, but production of muriform

basidiospores by Muribasidiospora is the most important

character distinguishing it from Exobasidium. Few

Muribasidiospora species have ever been recorded, but

all of them cause leaf-spot symptoms (Rajendren, 1968;

Crous et al., 2003). In this study, M. gordoniae induces

red leaf-spots on Gordonia axillaris, and its morphology

is typical of Muribasidiospora, except for the thickened

cell wall at the basal basidia. In this specimen, many

long cylindrical basidia were found, but the lack of

sterigmata on the top of basidia indicated immaturity. The

basidiospore size of M. gordoniae is different from that

of M. hesperidium (12-25 ¡Ñ 7-9 £gm) and of M. indica

(12-20 ¡Ñ 8-16 £gm) (Rajendren, 1968; Crous et al., 2003).

The reference on M. celtidis is, regrettably, unavailable

for comparison. M. gordoniae is thought to be a new

species, owing to the different hosts and morphology. In

the previous study, the phylogenetic relationship between

Exobasidium and Muribasidiospora was closer (Begerow

et al., 2001). The recorded hosts of Muribasidiospora are

Rhus (Anacardiaceae) and Celtis (Ulmaceae), but those

hosts

aren¡¦t infected by Exobasidium. However, Gordonia

axillaris can be infected by E. monosporum (Sawada,

1922) and M. gordoniae in Taiwan. The leaves infected by

E. monosporum produce near circular, yellow green spots

on the surface. Analyzing the ITS sequence, M. gordoniae

was more similar to Exobasidium species occurring on

Camellia than to those on Ericaceae. The suspected reason

is that both Camellia and Gordonia belong to Theaceae.

However, the ITS sequence of E. monosporum is absent,

and it may be more interesting to pursue the relationship

between E. monosporum and M. gordoniae.

Acknowledgements. This study was supported by

Grant NSC-95-2313-B-054-016 from National Science

Council, Taiwan, ROC. Thanks to Dr. Yu-Ming Ju and

Huei-Mei Hsieh of the Institute of Plant and Microbial

Biology, Academia Sinica, Taipei for their assistance

with the molecular biological experiments, and Miss Kai-

Leen Hsueh for her comment on an earlier version of this

manuscript.

LITERATURE CITED

Begerow, D., R. Bauer, and F. Oberwinkler. 2001.

Muribasidiospora: Microstrom atales or Exobasidiales.

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Begerow, D., R. Bauer, and F. Oberwinkler. 2002. The

Exobasidiales: an evolution hypothesis. Mycol. P rog. 1:

187-199.

Crous, P.W., J.Z. Groenewald, and G. Carroll. 2003.

Muribas idiospora indica caus ing a prominent leaf s pot

disease on Rhus lancea in South Africa. Aust. Plant Pathol.

32: 313-316.

Donk, M.A. 1974. Check list of European Hymenomycetous

Heterobasidiae: supplement and correction. Persoonia 8:

33-50.

Kirk, P.M., P.F. Cannon, J.C. David, and J.A. Stalpers. 2001.

Dictionary of the Fungi 9ed. CABI International, 655 pp.

Rajendren, R.B. 1968. Muribasidiospora¡VA new genus of the

Exobasidiaceae. Mycopath. Mycol. Appl. 36: 218-222.

Sawada, K. 1922. Descriptive Catalogue of the Formosan fungi

II. Rept. Dept. Agr. Gov¡¦t. Res. Inst. Formosa, 173 pp.

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