scholarly journals First Report of the Head Smut Fungus Tilletia maclaganii Infecting Switchgrass (Panicum virgatum) in Indiana

Plant Disease ◽  
2019 ◽  
Vol 103 (8) ◽  
pp. 2135
Author(s):  
G. E. Ruhl ◽  
T. Creswell ◽  
E. M. Karlsen-Ayala ◽  
B. Stefancik ◽  
K. Johnson ◽  
...  
Plant Disease ◽  
2019 ◽  
Vol 103 (3) ◽  
pp. 578 ◽  
Author(s):  
S. C. Kenaley ◽  
G. C. Bergstrom ◽  
Z. K. Montes Ortiz ◽  
A. Van Wallendael ◽  
D. B. Lowry ◽  
...  
Keyword(s):  

2001 ◽  
Vol 50 (6) ◽  
pp. 807-807 ◽  
Author(s):  
J. V. Etheridge ◽  
L. Davey ◽  
D. G. Christian

Plant Disease ◽  
2013 ◽  
Vol 97 (12) ◽  
pp. 1654-1654 ◽  
Author(s):  
A. L. Vu ◽  
M. M. Dee ◽  
J. Zale ◽  
K. D. Gwinn ◽  
B. H. Ownley

Knowledge of pathogens in switchgrass, a potential biofuels crop, is limited. In December 2007, dark brown to black irregularly shaped foliar spots were observed on ‘Alamo’ switchgrass (Panicum virgatum L.) on the campus of the University of Tennessee. Symptomatic leaf samples were surface-sterilized (95% ethanol, 1 min; 20% commercial bleach, 3 min; 95% ethanol, 1 min), rinsed in sterile water, air-dried, and plated on 2% water agar amended with 3.45 mg fenpropathrin/liter (Danitol 2.4 EC, Valent Chemical, Walnut Creek, CA) and 10 mg/liter rifampicin (Sigma-Aldrich, St. Louis, MO). A sparsely sporulating, dematiaceous mitosporic fungus was observed. Fungal plugs were transferred to surface-sterilized detached ‘Alamo’ leaves on sterile filter paper in a moist chamber to increase spore production. Conidia were ovate, oblong, mostly straight to slightly curved, and light to olive-brown with 3 to 10 septa. Conidial dimensions were 12.5 to 17 × 27.5 to 95 (average 14.5 × 72) μm. Conidiophores were light brown, single, multiseptate, and geniculate. Conidial production was polytretic. Morphological characteristics and disease symptoms were similar to those described for Bipolaris oryzae (Breda de Haan) Shoemaker (2). Disease assays were done with 6-week-old ‘Alamo’ switchgrass grown from seed scarified with 60% sulfuric acid and surface-sterilized in 50% bleach. Nine 9 × 9-cm square pots with approximately 20 plants per pot were inoculated with a mycelial slurry (due to low spore production) prepared from cultures grown on potato dextrose agar for 7 days. Cultures were flooded with sterile water and rubbed gently to loosen mycelium. Two additional pots were inoculated with sterile water and subjected to the same conditions to serve as controls. Plants were exposed to high humidity by enclosure in a plastic bag for 72 h. Bags were removed, and plants were incubated at 25/20°C with 50 to 60% relative humidity. During the disease assay, plants were kept in a growth chamber with a 12-h photoperiod of fluorescent and incandescent lighting. Foliar leaf spot symptoms appeared 5 to 14 days post-inoculation for eight of nine replicates. Control plants had no symptoms. Symptomatic leaf tissue was processed and plated as described above. The original fungal isolate and the pathogen recovered in the disease assay were identified using internal transcribed spacer (ITS) region sequences. The ITS region of rDNA was amplified with PCR and primer pairs ITS4 and ITS5 (4). PCR amplicons of 553 bp were sequenced, and sequences from the original isolate and the reisolated pathogen were identical (GenBank Accession No. JQ237248). The sequence had 100% nucleotide identity to B. oryzae from switchgrass in Mississippi (GU222690, GU222691, GU222692, and GU222693) and New York (JF693908). Leaf spot caused by B. oryzae on switchgrass has also been described in North Dakota (1) and was seedborne in Mississippi (3). To our knowledge, this is the first report of B. oryzae from switchgrass in Tennessee. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/, 28 June 2012. (2) J. M. Krupinsky et al. Can. J. Plant Pathol. 26:371, 2004. (3) M. Tomaso-Peterson and C. J. Balbalian. Plant Dis. 94:643, 2010. (4) T. J. White et al. Pages 315-322 in: PCR Protocols: a Guide to Methods and Applications. M. A. Innis et al. (eds), Acad. Press, San Diego, 1990.


Plant Disease ◽  
2012 ◽  
Vol 96 (1) ◽  
pp. 143-143 ◽  
Author(s):  
T. Tsukiboshi ◽  
M. Ebina ◽  
I. Okabe ◽  
K. Sugawara ◽  
K. Kouki

Guinea grass (Panicum maximum Jacq.) is an important C-4 perennial plant that grows in southern Japan. In March 2010, a smut disease was found in grass that is cultivated in the Ishigaki Islands, Okinawa, in southernmost Japan. Spikelets of susceptible cultivars were swollen and filled with gray spore masses and seed production was substantially reduced. Two single-spore isolates of a smut fungus were obtained from infected spikelets and deposited at the NIAS Genebank, Japan as MAFF511519 and 511520. The 28S rDNA sequences of the isolates were analyzed as described by Boekhout et al. (1). The 28S rDNA sequence (GenBank Accession No. AB647346) of isolate MAFF511519 matched that of Conidiosporomyces ayresii (GenBank Accession No. AY819017) isolated from P. maximum with 99.8% similarity. Spores were pale brown to brown, globose to subglobose, verrucose, and 14 to 16 × 15 to 18 μm in diameter with relatively thick walls of 2 to 3 μm. With scanning electron microscopy, warts appeared dense and short with pointed tips. Spores germinated under wet conditions and produced masses of basidiospores. Basidiospores were aseptate, long, cylindrical, straight to slightly curved, 20 to 37 × 2 to 3 μm, and often germinated into Y-shaped conidia. This description matches previous descriptions (3) of C. ayresii (Berk.) Vánky (Tilletia ayresii Berk.) of the smut pathogen of guinea grass (2). The smut fungus was identified as C. ayresii on the basis of morphology and molecular phylogenetic analysis. To produce inoculum, the isolates were grown on potato dextrose agar at 25°C in the dark for 7 days. Two plants of cv. Ryukyu 5-gou with half-flowering heads were grown in a greenhouse for approximately 1 month and then inoculated by atomizing them with conidial suspensions of each isolate (106 conidia/ml). A plant sprayed with sterilized distilled water served as the control. Inoculated heads were covered with plastic bags for 48 h at 25°C. After 30 days, all inoculated plants were symptomatic with swollen spikelets releasing gray spores. Controls remained asymptomatic. The smut fungus was reisolated from released gray spores, confirming Koch's postulates. To our knowledge, this is the first report of smut caused by C. ayresii on guinea grass in Japan. References: (1) T. Boekhout et al. Stud. Mycol. 38:175, 1995. (2) J. M. Lenné and P. Trutmann. Diseases of Tropical Pasture Plants. CAB International, Wallingford, UK, 1994. (3) K. Vánky and R. Bauer. Mycotaxon 43:427, 1992.


Plant Disease ◽  
2018 ◽  
Vol 102 (2) ◽  
pp. 466-466 ◽  
Author(s):  
L. M. Kumar ◽  
J. A. Foster ◽  
C. McFarland ◽  
M. Malapi-Wight

Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1192-1192 ◽  
Author(s):  
K. D. Waxman ◽  
G. C. Bergstrom

Switchgrass (Panicum virgatum L.) is a perennial grass with biofuel potential. From 2007 to 2010, foliar lesions were observed on first year and mature stands of switchgrass in various locations in New York. Foliar lesions were purple, elliptical (up to 1 cm) with either distinct or diffuse margins, and occasionally with yellow halos and/or white necrotic centers. After 2 to 5 days of moist chamber incubation, surface-sterilized, symptomatic leaf tissue produced conidia that when streaked onto potato dextrose agar containing 0.3 g of streptomycin per liter gave rise to cultures with gray-to-black mycelium that developed brown conidia. The fungus was identified as Bipolaris oryzae (Breda de Haan) Shoemaker on the basis of conidial morphology (1,2). Conidiophores were brown, straight, cylindrical, and multiseptate. Conidia were brown, curved, ellipsoidal tapering to rounded ends, with 3 to 14 septa. Conidia averaged 105 μm (54 to 160 μm) long and 16 μm (12 to 20 μm) wide. Sequences of the glyceraldehyde-3-phosphate dehydrogenase (GDP) gene of three isolates from Tompkins County (Cornell Accession and corresponding GenBank Nos.: Bo005NY07 [cv. Cave-in-Rock], JF521648; Bo006NY07 [cv. Kanlow], JF521649; and Bo038NY07 [cv. Shawnee], JF521650) exhibited 100% nucleotide identity to B. oryzae isolates (GenBank Nos. AY277282–AY277285) collected from switchgrass in North Dakota (1). Sequences of the rDNA internal transcribed spacer (ITS) regions of the isolates (Cornell Accession and corresponding GenBank Nos.: Bo005NY07, JF693908; Bo006NY07, JF693909; and Bo038NY07, JF693910) exhibited 100% nucleotide identity to B. oryzae isolates (GenBank Nos. GU222690–GU222693) collected from switchgrass in Mississippi (3). Pathogenicity of two of the sequenced isolates (Bo006NY07 and Bo038NY07) along with one other isolate (Bo116NY09 from ‘Cave-in-Rock’ in Cayuga County) was evaluated in the greenhouse. Six- to eight-week-old switchgrass plants were inoculated with conidial suspensions (40,000 conidia/ml) of B. oryzae. Inoculum or sterilized water was applied until runoff. There were three plants per treatment of each of ‘Blackwell’, ‘Carthage’, ‘Cave-in-Rock’, ‘Kanlow’, ‘Shawnee’, ‘Shelter’, and ‘Sunburst’. After inoculum had dried, plants were placed in a mist chamber for 24 h and then returned to the greenhouse. Symptoms developed 2 to 4 days after inoculation for all cultivars. No symptoms developed on the control plants. Foliar lesions closely resembled those observed in the field. B. oryzae was consistently reisolated from symptomatic tissue collected from greenhouse experiments. B. oryzae was first reported as a pathogen of switchgrass in North Dakota (1) and more recently in Mississippi (3). To our knowledge, this is the first report of B. oryzae causing a leaf spot on switchgrass in New York. Observation of severe leaf spot in several field plots suggests that switchgrass populations should be screened for their reaction to regional isolates of B. oryzae prior to expanded production of switchgrass as a biofuel crop. References: (1) J. M. Krupinsky et al. Can. J. Plant Pathol. 26:371 2004. (2) R. A. Shoemaker. Can. J. Bot. 37:883, 1959. (3) M. Tomaso-Peterson and C. J. Balbalian. Plant Dis. 94:643 2010.


Plant Disease ◽  
2016 ◽  
Vol 100 (2) ◽  
pp. 536-536
Author(s):  
M. Abbasi ◽  
M. C. Aime ◽  
G. E. Ruhl ◽  
T. C. Creswell
Keyword(s):  

Plant Disease ◽  
2010 ◽  
Vol 94 (5) ◽  
pp. 643-643 ◽  
Author(s):  
M. Tomaso-Peterson ◽  
C. J. Balbalian

‘Alamo’ switchgrass (Panicum virgatum L.) seedlings growing in a soilless mix exhibiting dark brown, irregular-shaped foliar lesions with black borders were submitted to the Mississippi State University Plant Disease Diagnostic Laboratory in the summer of 2009 from a local forest products company. Symptomatic tissues were plated onto water agar (WA) and incubated for 21 days on a laboratory bench top with a 12-h photoperiod at 22°C. An asexual, sporulating, dematiaceous hyphomycete identified as Bipolaris oryzae (Breda de Haan) Shoemaker was observed. Conidiophores were single, mostly straight, multiseptate, brown, and ranging from 138 to 306 × 7.7 to 15.3 μm and averaged 221.6 × 10.7 μm. Conidia were golden brown, multiseptate, ranging from 3 to 10 septa, straight to slightly curved to fusoid, wider midway, and tapering toward the terminal cells. Conidia measured 40.8 to 109.7 × 10.2 to 20.4 μm and averaged 75.8 × 13.8 μm. Morphological characteristics of B. oryzae were similar to those described by Drechsler (1) and Sivanesan (3). The internal transcribed spacer (ITS) region of ribosomal DNA from four pure culture colonies derived from single conidia was amplified by PCR using ITS1 and ITS4 primers. The resultant 572 bp was sequenced for isolates 86 through 89 (GenBank Accession Nos. GU222690–93). The sequences were 99% similar to the sequence of B. oryzae strain ATCC-MYA 3330 (GenBank No. FJ746665) isolated from P. virgatum. Pathogenicity of isolates 86 and 88 was confirmed by inoculating sterile potting mix with a fungal slurry. Sterile Alamo switchgrass seeds were sown into the infested soil in Magenta boxes and incubated for 6 weeks in a growth chamber with a 14-h photoperiod at 30°C. Leaf lesions and leaf blight were observed in seedling stands growing in B. oryzae-infested soil. Lesions were excised and plated onto WA. Sporulation of B. oryzae was observed on symptomatic tissue. In the interim, 300 nonsterilized Alamo switchgrass seeds of the same seed lot as the original symptomatic seedlings and originating from Oklahoma were plated onto WA (10 seed per plate). The seeds were incubated on the bench top as previously described. The experiment was repeated and B. oryzae colonized 1.4% of the total switchgrass seeds evaluated, indicating seed transmission and subsequent seedling infection as previously observed in the original seedlings. Leaf spot, caused by B. oryzae, was first reported as a new disease of switchgrass in North Dakota (2). In the summer of 2009, the authors observed leaf spot in four cultivars of switchgrass, including Alamo, growing in research plots in Webster County, MS. Twenty-two isolates of B. oryzae were recovered from diseased leaves of these switchgrass cultivars. To our knowledge, this is the first report of B. oryzae causing leaf spot of switchgrass in Mississippi, which broadens the natural distribution of this disease. References: (1) C. Drechlser. J. Agric. Res. 24:641, 1923. (2) J. M. Krupinsky et al. Can. J. Plant Pathol. 26:371, 2004. (3) A. Sivanesan. Mycol. Pap. 158:201, 1987.


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