scholarly journals Characterization of a New Subgroup of Rhizoctonia solani Anastomosis Group 1 (AG-1-ID), Causal Agent of a Necrotic Leaf Spot on Coffee

2001 ◽  
Vol 91 (11) ◽  
pp. 1054-1061 ◽  
Author(s):  
Achmadi Priyatmojo ◽  
Verma E. Escopalao ◽  
Naomi G. Tangonan ◽  
Cecilia B. Pascual ◽  
Haruhisa Suga ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Fragment Length Polymorphism ◽  
Hyphal Growth ◽  
Anastomosis Group ◽  
Fatty Acid Profiles ◽  
Pathogenicity Tests ◽  
Necrotic Spots ◽  
Random Amplified Polymorphism Dna ◽  
Group 1

A new foliar disease on coffee leaves was observed in Mindanao, Philippines, in 1996. The symptoms appeared as large circular or irregularly shaped necrotic areas with small circular necrotic spots (1 mm or less in diameter) usually found around the periphery of the large necrotic areas. Rhizoctonia solani was consistently isolated from these diseased coffee leaves. Isolates obtained were multinucleate (3 to 12 nuclei per hyphal cell), had an optimum temperature for hyphal growth at 25°C, prototrophic for thiamine, and anastomosed with tester isolates belonging to R. solani anastomosis group 1 (AG-1). Mature cultures on potato dextrose agar (PDA) were light to dark brown. Sclerotia, light brown to brown, were formed on the surface of PDA and covered the whole mature colony culture. Individual sclerotia often aggregated into large clumps (3 to 8 mm in diameter) and their color was brown to dark brown. In pathogenicity tests, isolates from coffee caused necrotic symptoms on coffee leaves, whereas isolates of AG-1-IA (not isolated from coffee), 1-IB, and 1-IC did not. The results of analyses of restriction fragment length polymorphism of ribosomal DNA internal transcribed spacer, random amplified polymorphism DNA, and fatty acid profiles showed that R. solani isolates from coffee are a population of AG-1 different from AG-1-IA, 1-IB, and 1-IC. These results suggest that R. solani isolates from coffee represent a new subgroup distinct from AG-1-IA, 1-IB, and 1-IC. A new subgroup ID (AG-1-ID) is proposed.

scholarly journals Characterization of a New Anastomosis Group (AG-W) of Binucleate Rhizoctonia, Causal Agent for Potato Stem Canker

Plant Disease ◽  
2015 ◽  
Vol 99 (12) ◽  
pp. 1757-1763 ◽  
Author(s):  
Y. G. Yang ◽  
C. Zhao ◽  
Z. J. Guo ◽  
X. H. Wu
Keyword(s):  
Fragment Length Polymorphism ◽  
Stem Canker ◽  
Anastomosis Group ◽  
Northeastern China ◽  
Binucleate Rhizoctonia ◽  
Rdna Its ◽  
Its Regions ◽  
Pathogenicity Tests ◽  
Reference Strains

Two binucleate Rhizoctonia (BNR) isolates were recovered from potato cankered stems in Heilongjiang Province, northeastern China. Their cultural appearance on potato dextrose agar remained whitish as the cultures aged. White monilioid cells formed in the fluffy aerial hyphae, whereas no sclerotia appeared during the incubation. The two isolates could anastomose with each other, but they failed to anastomose with reference strains of BNR from AG-A to AG-Q, and AG-U. Analyses of restriction fragment length polymorphism (RFLP) of internal transcribed spacer of ribosomal DNA (rDNA-ITS) regions confirmed that these two isolates differed from the reference strains. The phylogenetic tree based on the sequences of rDNA-ITS regions showed that they were located in a distinct clade from other BNR AGs. These collective results suggested that the isolates recovered from potato in this study belonged to a new BNR AG designated as AG-W. Pathogenicity tests under glasshouse conditions revealed that both isolates were able to cause brown, dry, and slightly sunken lesions on potato subterranean stems. To our knowledge, this is the first report of the AG-W causing potato disease in China as well as worldwide.

Highly polymorphic microsatellite loci in the rice- and maize-infecting fungal pathogen Rhizoctonia solani anastomosis group 1 IA

2008 ◽  
Vol 8 (3) ◽  
pp. 686-689 ◽  
Author(s):  
M. ZALA ◽  
B. A. MCDONALD ◽  
J. BERNARDES DE ASSIS ◽  
M. B. CIAMPI ◽  
M. STORARI ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Microsatellite Loci ◽  
Fungal Pathogen ◽  
Anastomosis Group ◽  
Polymorphic Microsatellite ◽  
Group 1

Characterization of a new subgroup of Rhizoctonia solani anastomosis group 3 (AG-3 TM) associated with tomato leaf blight

2020 ◽  
Vol 86 (6) ◽  
pp. 457-467
Author(s):  
Tomoo Misawa ◽  
Daisuke Kurose ◽  
Kuniaki Shishido ◽  
Takeshi Toda ◽  
Shiro Kuninaga
Keyword(s):  
Rhizoctonia Solani ◽  
Anastomosis Group ◽  
Tomato Leaf ◽  
Leaf Blight ◽  
Group 3

Nuclear Behavior in Homokaryotic and Heterokaryotic Fruiting of Thanatephorus cucumeris (Rhizoctonia Solani) Anastomosis Group 1, Subgroup IC

Mycologia ◽  
1997 ◽  
Vol 89 (3) ◽  
pp. 361 ◽  
Author(s):  
Maria C. Julian ◽  
Annette M. Dullemans ◽  
Cor H. van Silfhout ◽  
Jaap Keijer
Keyword(s):  
Rhizoctonia Solani ◽  
Anastomosis Group ◽  
Thanatephorus Cucumeris ◽  
Nuclear Behavior ◽  
Group 1

scholarly journals Characterization of Populations of Rhizoctonia solani in Paddy Rice Fields in Côte d'Ivoire

1999 ◽  
Vol 89 (5) ◽  
pp. 414-420 ◽  
Author(s):  
S. Banniza ◽  
A. A. Sy ◽  
P. D. Bridge ◽  
S. A. Simons ◽  
M. Holderness
Keyword(s):  
Rhizoctonia Solani ◽  
Cote D'ivoire ◽  
Côte D’Ivoire ◽  
Morphological Characters ◽  
Morphological Characterization ◽  
Anastomosis Group ◽  
Cote D’Ivoire ◽  
Côte D'ivoire ◽  
Length Polymorphisms

Isolates of Rhizoctonia solani were obtained from plant and soil samples that had been systematically collected in a field experiment in Côte d'Ivoire to study the diversity of the pathogen and the influence of three different rice rotations on the pathogen population. Characterization by morphology, anastomosis testing, pathogenicity testing, and restriction fragment length polymorphisms (RFLPs) of AT-rich DNA (AT-DNA) showed that there were no differences in isolates from different experimental plots, suggesting that the soil as well as the plant population of the fungus was indistinguishable throughout the experiment and was not influenced by crop rotation. Analysis of AT-DNA showed that the isolates obtained from plant material and one from soil shared a distinct banding pattern, identical with the AT-DNA RFLP obtained for the reference strain of anastomosis group 1 (AG-1). The remaining soil isolates produced a consistent RFLP pattern that was distinct from that of the plant isolates. Morphological characterization of isolates produced two major clusters consisting of the same groups of isolates as found by AT-DNA RFLP. Diversity in morphological characters was much higher in plant than in soil isolates and indicated that the population might consist of several clones. Anastomosis testing revealed that soil as well as plant isolates were able to fuse with the tester strain of AG-1. Significant differences in disease severity were observed between the two groups of isolates in pathogenicity tests on rice plants, with plant isolates being distinctively more virulent.

scholarly journals Characterization of Verticillium albo-atrum Field Isolates Using Pathogenicity Data and AFLP Analysis

Plant Disease ◽  
2003 ◽  
Vol 87 (6) ◽  
pp. 633-638 ◽  
Author(s):  
Sebastjan Radišek ◽  
Jernej Jakše ◽  
Andrej Simončič ◽  
Branka Javornik
Keyword(s):  
Fragment Length Polymorphism ◽  
Economic Losses ◽  
Aflp Analysis ◽  
Mild Form ◽  
Aflp Data ◽  
Green Pepper ◽  
Clear Separation ◽  
Pathogenicity Tests ◽  
Verticillium Albo Atrum

Since 1997, hop wilt induced by a virulent pathotype of Verticillium albo-atrum has caused considerable economic losses in hop fields in Slovenia. In all, 20 isolates of V. albo-atrum, including 12 from plants affected with the lethal form (PG2) of hop wilt, 6 from plants with the mild form (PG1), 1 from cucumber, and 1 from petunia, as well as 1 isolate of V. dahliae each from hop and green pepper, were analyzed by amplified fragment length polymorphism (AFLP). Differences in the virulence of hop isolates were confirmed by pathogenicity tests on hop cultivars. The AFLP method was optimized for analysis of these fungi and 7 of 39 primer combinations tested were used for the analysis of polymorphism among isolates. Cluster analysis of AFLP data divided the isolates into two, well-separated V. albo-atrum and V. dahliae clusters, confirming that the two species are genetically distinct. Within the V. albo-atrum cluster, isolates were further separated into two distinct groups: the A1 group contained PG1 hop pathotype and cucumber and petunia isolates, and the A2 group all hop isolates of the PG2 pathotype. Minor genetic variation was detected within pathotype-associated AFLP groups, but the clear separation of V. albo-atrum hop isolates according to their level of virulence shows genetic differentiation among hop V. albo-atrum pathotypes.

scholarly journals Characterization of AG-13, a Newly Reported Anastomosis Group of Rhizoctonia solani

2002 ◽  
Vol 92 (8) ◽  
pp. 893-899 ◽  
Author(s):  
D. E. Carling ◽  
R. E. Baird ◽  
R. D. Gitaitis ◽  
K. A. Brainard ◽  
S. Kuninaga
Keyword(s):  
Rhizoctonia Solani ◽  
Internal Transcribed Spacer ◽  
Aerial Mycelium ◽  
Its Region ◽  
The United States ◽  
Anastomosis Group ◽  
Its Regions ◽  
Cotton Plants ◽  
Agar Surface

Rhizoctonia solani anastomosis group (AG)-13 was collected from diseased roots of field grown cotton plants in Georgia in the United States. Isolates of AG-13 did not anastomose with tester isolates of AG-1 through AG-12. Mycelium of all isolates of AG-13 were light brown but darkened as cultures aged. All isolates produced aerial mycelium. Concentric rings were visible after 3 to 4 days of growth but disappeared as cultures aged and darkened. Individual sclerotia were up to 1.5 mm in diameter, similar in color to the mycelium, and generally embedded in the agar. Clumps of sclerotia up to 5 mm in diameter were produced on the agar surface. All attempts to induce basidiospore production were unsuccessful. The 5.8S region of the rDNA from isolates of AG-13 was identical in length and sequence to isolates of all other AGs of R. solani. Length and sequence of the internal transcribed spacer (ITS) regions of rDNA from isolates of AG-13 were unique among AGs of R. solani. Similarity between AG-13 and other AGs of R. solani ranged from 68 to 85% for ITS region 1 and 85 to 95% for ITS region 2. Selected isolates of AG-13 caused minor or no damage to barley, cauliflower, cotton, lettuce, potato, and radish in laboratory or greenhouse studies.

scholarly journals Characterization of Mycorrhizal Isolates of Rhizoctonia solani from an Orchid, Including AG-12, a New Anastomosis Group

1999 ◽  
Vol 89 (10) ◽  
pp. 942-946 ◽  
Author(s):  
D. E. Carling ◽  
E. J. Pope ◽  
K. A. Brainard ◽  
D. A. Carter
Keyword(s):  
Rhizoctonia Solani ◽  
Leaf Litter ◽  
Anastomosis Group ◽  
Thanatephorus Cucumeris ◽  
Pathogenic Potential ◽  
Agar Surface ◽  
Extensive Damage

Isolates of Rhizoctonia solani collected from mycorrhizal orchid (Pterostylis acuminata) plants and adjacent leaf litter were characterized. Of 23 selected isolates, 20 were members of a new anastomosis group (AG-12) and the rest were members of AG-6. There were no bridging anastomosis reactions observed between AG-12 and other AGs of R. solani. Among the 20 isolates of AG-12 evaluated, 18 vegetatively compatible populations were detected, indicating diversity within the AG. Mature cultures were dark brown, as were mature sclerotia. Some cultures produced alternating dark- and light-colored concentric rings, with sclerotia forming in the darker rings. Most cultures were appressed to the agar surface. In tests run to characterize pathogenic potential, selected mycorrhizal isolates of AG-12 and AG-6 did little damage to potato and barley seedlings, moderate damage to head lettuce seedlings, and more extensive damage to seedlings of cauliflower and radish. Isolates of AG-12 have not been observed to fruit in nature, and all attempts to induce formation of the teleomorph (Thanatephorus cucumeris) in the laboratory by selected isolates of AG-12 failed.

scholarly journals First Report of Web Blight on Verbena Caused by Rhizoctonia solani

Plant Disease ◽  
2000 ◽  
Vol 84 (4) ◽  
pp. 492-492 ◽  
Author(s):  
G. E. Holcomb ◽  
D. E. Carling
Keyword(s):  
Rhizoctonia Solani ◽  
Fungal Pathogen ◽  
Baton Rouge ◽  
Anastomosis Group ◽  
First Report ◽  
Foliage Blight ◽  
Pathogenicity Tests ◽  
Stem Lesions ◽  
Web Blight ◽  
Branch Death

Web blight was observed on verbena (Verbena × hybrida) during July 1999 in a cultivar trial planting at Burden Research Plantation in Baton Rouge, LA. Foliage blight, stem lesions, and branch death were common symptoms on 12 of 24 cultivars in the trial. Plant death occurred in cvs. Babylon Florena (one of four plants), Purple Princess (two of four plants), and Taylortown Red (two of four plants). Isolations from infected leaves and stems on acidified water agar consistently yielded a fungus with the mycelial and cultural characteristics of Rhizoctonia solani. Pathogenicity tests were carried out by placing 5-day-old fungal mycelial plugs, grown on acidified potato dextrose agar, at the base of healthy verbena stems and holding plants in a dew chamber at 26°C. After 3 days, foliage blight and stem lesions appeared on inoculated plants, and plants were moved to a greenhouse where temperatures ranged from 23 to 32°C. Seven of nine inoculated plants died after 7 days; noninoculated plants remained healthy. The fungal pathogen was reisolated from all inoculated plants. The fungus was identified as R. solani anastomosis group (AG)-1 IB based on multinucleate condition, type of sclerotia produced, and ability to anastomose with R. solani tester isolates of AG-1 IB. This is the first report of web blight on verbena.

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