Full TGIF Record # 282568
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DOI:10.1094/PDIS-09-16-1349-PDN
Web URL(s):http://apsjournals.apsnet.org/doi/full/10.1094/PDIS-09-16-1349-PDN
    Last checked: 04/10/2017
Publication Type:
i
Report
Author(s):Farinas, C.; Villari, C.; Martin, D.; Taylor, N. J.; Hand, F. Peduto
Author Affiliation:Farinas, Villari, and Martin: Department of Plant Pathology, The Ohio State University, Columbus, OH; Taylor: C. Wayne Ellett Plant and Pest Diagnostic Clinic, The Ohio State University, Reynoldsburg, OH; Hand: Department of Plant Pathology, The Ohio State University, Columbus, OH
Title:Magnaporthe oryzae perennial ryegrass pathotype causes leaf spots and blight on Japanese forest grass in Ohio
Section:Disease notes: Diseases caused by fungi and fungus-like organisms
Other records with the "Disease notes: Diseases caused by fungi and fungus-like organisms" Section
Source:Plant Disease. Vol. 101, No. 3, March 2017, p. 507.
Publishing Information:[Washington, D.C.]: Bureau of Plant Industry, U.S. Dept. of Agriculture
# of Pages:1
Related Web URL:http://apsjournals.apsnet.org/doi/suppl/10.1094/PDIS-09-16-1349-PDN/suppl_file/PDIS-09-16-1349-PDN.sf1.pdf
    Last checked: 04/10/2017
    Requires: PDF Reader
    Notes: Supplementary figure S1
Keywords:TIC Keywords: Disease evaluation; Disease identification; Disease specificity; Hakonechloa macra; Leaf blight; Leaf spot; Lolium perenne; Pyricularia grisea; Oryza sativa; Pathogenicity; Triticum
Cultivar Names:All Gold; Aureola; Bravo; Nipponbare
Geographic Terms:Ohio
Abstract/Contents:"Japanese forest grass (Hakonechloa macra) is a slow growing deciduous perennial C3 plant popularly used as a groundcover in shady landscapes. In August 2015, H. macra cv. All Gold plants grown in a commercial nursery in Ohio exhibited dark-brown to black, 1 to 3 mm diameter, necrotic spots on leaves that were surrounded by a brown halo. Leaf tips were blighted and twisted. Incubation of symptomatic leaves in a moist chamber induced grayish-white fungal sporulation. Spores were suspended in sterile water and spread onto PDA plates. Representative colonies were transferred to oatmeal agar medium and incubated at 21°C under constant light for 7 days. Developing colonies were dark gray and reached in average 5.0 cm diameter (n = 3). The fungus produced a dark gray mat of conidiophores with small amounts of white, filamentous mycelium on the edges. Conidia were 3-celled, papillate at the wider end, and narrowed to a tip at the opposite end. Conidia measured (1) 23.7 to 35.2 (1) x (1) 6.07 to 9.45 (1) μm (n = 50). Based on morphological characteristics, the fungus was identified as Magnaporthe oryzae (Couch and Kohn 2002). Identification of one representative isolate was confirmed by sequence comparison of the internal transcribed spacer region (ITS1-5.8S-ITS2) with sequences available in GenBank, resulting in 99% homology to M. oryzae (JQ747492.1) with 100% coverage (GenBank accession no. KY070277). Since different host-specialized forms of M. oryzae can occur on gramineous crops, we aimed to further identify the isolates pathotype by means of pathogenicity testing and genetic characterization. Pathogenicity tests were conducted on three inoculated and three noninoculated plants of each of the following species: 2-week-old H. macra cvs. Aureola and All Gold; 2-week-old perennial ryegrass; 7-week-old wheat cv. Bravo; and 3-week-old rice cv. Nipponbare. All plants were inoculated by spraying the aboveground plant tissues with a suspension of 3 x 105 spores ml-1 in 0.05% v/v Tween 20 solution. Control plants received sterile aqueous 0.05% v/v Tween 20 solution. After inoculation, plants were maintained in a greenhouse at 28°C and 98% relative humidity. Straw-colored lesions surrounded by a dark necrotic border were observed on the inoculated H. macra blades 4 days post inoculation followed by leaf tip blight 1 week post inoculation. On perennial ryegrass, typical gray leaf spot symptoms were visible 4 days post inoculation. On rice, no symptoms were observed. On wheat, bleaching of the spikes was observed 1 week post inoculation. In all cases where symptomatic lesions were observed, incubation for 24 h in a moist chamber induced abundant spore production. The pathogen was reisolated from the symptomatic tissues and its identity confirmed by morphological observation, which in the case of H. macra fulfilled Kochs postulates. In all cases, control plants remained asymptomatic. The isolate was further tested with a LAMP PCR primer set specific to the M. oryzae perennial ryegrass pathotype (Villari et al. 2017), which resulted in positive amplification. M. oryzae perennial ryegrass pathotype is widely distributed on grasses in several regions of the U.S. (Uddin et al. 2003; Viji et al. 2001); however, to the best of our knowledge, this is the first published report of its occurrence on H. macra in Ohio. The ability of grass isolates to cross-infect important food crops under laboratory conditions highlights the need for epidemiological studies in field settings."
Language:English
References:4
ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Farinas, C., C. Villari, D. Martin, N. J. Taylor, and F. P. Hand. 2017. Magnaporthe oryzae perennial ryegrass pathotype causes leaf spots and blight on Japanese forest grass in Ohio. Plant Disease. 101(3):p. 507.
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DOI: 10.1094/PDIS-09-16-1349-PDN
Web URL(s):
http://apsjournals.apsnet.org/doi/full/10.1094/PDIS-09-16-1349-PDN
    Last checked: 04/10/2017
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