Genetic diversity among mycelial compatibility groups of Sclerotium rolfsii (teleomorph Athelia rolfsii) and S. delphinii

2001 ◽  
Vol 105 (5) ◽  
pp. 537-546 ◽  
Author(s):  
Zamir K. Punja ◽  
Li-Juan Sun
Keyword(s):  
Genetic Diversity ◽  
Sclerotium Rolfsii ◽  
Athelia Rolfsii ◽  
Mycelial Compatibility

scholarly journals Sequence Variation in Two Protein-Coding Genes Correlates with Mycelial Compatibility Groupings in Sclerotium rolfsii

2013 ◽  
Vol 103 (5) ◽  
pp. 479-487 ◽  
Author(s):  
Efrén Remesal ◽  
Blanca B. Landa ◽  
María del Mar Jiménez-Gasco ◽  
Juan A. Navas-Cortés
Keyword(s):  
Rna Polymerase Ii ◽  
Sequence Variation ◽  
Geographic Origin ◽  
Sclerotium Rolfsii ◽  
Nuclear Ribosomal Dna ◽  
Causal Organism ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Wide Range ◽  
Mycelial Compatibility

Populations of Sclerotium rolfsii, the causal organism of Sclerotium root-rot on a wide range of hosts, can be placed into mycelial compatibility groups (MCGs). In this study, we evaluated three different molecular approaches to unequivocally identify each of 12 previously identified MCGs. These included restriction fragment length polymorphism (RFLP) patterns of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA (rDNA) and sequence analysis of two protein-coding genes: translation elongation factor 1α (EF1α) and RNA polymerase II subunit two (RPB2). A collection of 238 single-sclerotial isolates representing 12 MCGs of S. rolfsii were obtained from diseased sugar beet plants from Chile, Italy, Portugal, and Spain. ITS-RFLP analysis using four restriction enzymes (AluI, HpaII, RsaI, and MboI) displayed a low degree of variability among MCGs. Only three different restriction profiles were identified among S. rolfsii isolates, with no correlation to MCG or to geographic origin. Based on nucleotide polymorphisms, the RPB2 gene was more variable among MCGs compared with the EF1α gene. Thus, 10 of 12 MCGs could be characterized utilizing the RPB2 region only, while the EF1α region resolved 7 MCGs. However, the analysis of combined partial sequences of EF1α and RPB2 genes allowed discrimination among each of the 12 MCGs. All isolates belonging to the same MCG showed identical nucleotide sequences that differed by at least in one nucleotide from a different MCG. The consistency of our results to identify the MCG of a given S. rolfsii isolate using the combined sequences of EF1α and RPB2 genes was confirmed using blind trials. Our study demonstrates that sequence variation in the protein-coding genes EF1α and RPB2 may be exploited as a diagnostic tool for MCG typing in S. rolfsii as well as to identify previously undescribed MCGs.

First report of Sclerotium rolfsii (=Athelia rolfsii) associated with root rot and leaf spot on clove basil (Ocimum gratissimum L.) in India

2021 ◽  
Author(s):  
Shivannegowda Mahadevakumar ◽  
Yelandur Somaraju Deepika ◽  
Kandikere Ramaiah Sridhar ◽  
Kestur Nagaraj Amruthesh ◽  
Nanjaiah Lakshmidevi
Keyword(s):  
Leaf Spot ◽  
Root Rot ◽  
Sclerotium Rolfsii ◽  
First Report ◽  
Ocimum Gratissimum ◽  
Athelia Rolfsii

scholarly journals Evaluation of the virulence of Sclerotium rolfsii isolates on Arachis hypogaea and screening for resistant genotypes in greenhouse conditions

2015 ◽  
Vol 8 (1) ◽  
pp. 1-11 ◽  
Author(s):  
A.A. Eslami ◽  
S.A. Khodaparast ◽  
S. Mousanejad ◽  
F. Padasht Dehkaei
Keyword(s):  
Plant Height ◽  
Block Design ◽  
Sclerotium Rolfsii ◽  
Soil Surface ◽  
Lesion Length ◽  
Randomized Block Design ◽  
Wide Range ◽  
Mycelial Compatibility ◽  
Pathogenicity Tests ◽  
Plant Maturity

Summary Sclerotium rolfsii is a soil borne pathogen responsible for root and stem rot on a wide range of crops. This study was conducted to identify the virulence of different S. rolfsii isolates on a susceptible local peanut germplasm and determine the resistance of 20 peanut genotypes to the most virulent isolate and also the relationship between virulence and mycelial compatibility groups (MCGs). Seventy eight isolates of this fungus from 10 host plants and six known MCGs were used in the experiment. The experiment was done in greenhouse conditions (25±5°C) using a complete randomized block design with three replications. Pots containing sterile soil (pH=6.7) were inoculated with barley seeds colonized by each isolate separately before being seeded with the peanut germplasm. Disease severity was assessed by scoring the wilting, yellowing or death of plants, mycelia or sclerotia production on the soil surface or on plant stem, stem area affected (%) and stem lesion length, at the stage of plant maturity. Also, shoot wet weight and plant height were recorded at this stage. According to the results of the pathogenicity tests, all of the isolates were virulent on the susceptible peanut germplasm and the virulence diff ered signifi cantly between the isolates (P≤0.01). There was no relationship between the virulence of the five groups of isolates identified in the present study and the MCGs. The peanut genotype 140, which was better than the others based on seed size, plant height and the canopy size, was also the most resistant one

scholarly journals Monitoring Fungicide Sensitivity Levels and Mycelial Compatibility Groupings of Sclerotium rolfsii Isolates from Florida Peanut Fields

2017 ◽  
Vol 44 (2) ◽  
pp. 83-92 ◽  
Author(s):  
K. Khatri ◽  
S. Kunwar ◽  
R. L. Barocco ◽  
N. S. Dufault
Keyword(s):  
Management Practices ◽  
Phenotypic Diversity ◽  
Sclerotium Rolfsii ◽  
Morphological Characteristics ◽  
Morphological Diversity ◽  
Fungicide Sensitivity ◽  
Dose Effects ◽  
Mycelial Compatibility ◽  
Monitoring Survey ◽  
High Level

ABSTRACT Sclerotium rolfsii, the causal agent of peanut stem rot, is a diverse pathogen that has exhibited decreases in sensitivity to fungicides in areas where they are frequently applied. To better understand this pathogen's diversity and its response to various fungicides in Florida, a monitoring survey was done to examine isolates from several peanut producing areas using morphological characteristics, mycelial compatibility groupings and fungicide sensitivity profiles. A high level of morphological diversity was observed among a small number (N = 15) of isolates which was affirmed by both Shannon-Weiner (E = 0.812) and Simpson's (D = 0.280) indices. However, despite this high level of diversity, fungicide sensitivity of these isolates to flutolanil (EC50 = 0.031 ppm) and tebuconazole (EC50 = 0.008 ppm) appears to remain relatively unchanged when compared to a previous baseline study. Utilizing a small number of isolates, this monitoring survey indicated the EC50 values for the products azoxystrobin (EC50 = 0.050 ppm), prothioconazole (EC50 = 0.213 ppm), penthiopyrad (EC50 = 0.016 ppm) and solatenol (EC50 = 0.005 ppm). A trend for hormesis was also noted in this survey (e.g. flutolanil), but further research is necessary to better understand sub-lethal fungicide dose effects on increasing mycelial growth. It is apparent from these results that despite the high levels of phenotypic diversity in S. rolfsii populations, current fungicide management practices should remain effective for disease control.

scholarly journals Purification and Characterization of Cellobiose Dehydrogenase from the Plant Pathogen Sclerotium(Athelia) rolfsii

2001 ◽  
Vol 67 (4) ◽  
pp. 1766-1774 ◽  
Author(s):  
Ursula Baminger ◽  
Sai S. Subramaniam ◽  
V. Renganathan ◽  
Dietmar Haltrich
Keyword(s):  
Sclerotium Rolfsii ◽  
Cation Radical ◽  
Molecular Size ◽  
Extracellular Enzyme ◽  
Cellobiose Dehydrogenase ◽  
Phytopathogenic Fungus ◽  
Athelia Rolfsii ◽  
Heme Domain ◽  
Acid Cation

ABSTRACT Cellobiose dehydrogenase (CDH) is an extracellular hemoflavoenzyme produced by several wood-degrading fungi. In the presence of a suitable electron acceptor, e.g., 2,6-dichloro-indophenol (DCIP), cytochromec, or metal ions, CDH oxidizes cellobiose to cellobionolactone. The phytopathogenic fungus Sclerotium rolfsii (teleomorph: Athelia rolfsii) strain CBS 191.62 produces remarkably high levels of CDH activity when grown on a cellulose-containing medium. Of the 7,500 U of extracellular enzyme activity formed per liter, less than 10% can be attributed to the proteolytic product cellobiose:quinone oxidoreductase. As with CDH from wood-rotting fungi, the intact, monomeric enzyme from S. rolfsii contains one heme b and one flavin adenine dinucleotide cofactor per molecule. It has a molecular size of 101 kDa, of which 15% is glycosylation, and a pI value of 4.2. The preferred substrates are cellobiose and cellooligosaccharides; additionally, β-lactose, thiocellobiose, and xylobiose are efficiently oxidized. Cytochrome c (equine) and the azino-di-(3-ethyl-benzthiazolin-6-sulfonic acid) cation radical were the best electron acceptors, while DCIP, 1,4-benzoquinone, phenothiazine dyes such as methylene blue, phenoxazine dyes such as Meldola's blue, and ferricyanide were also excellent acceptors. In addition, electrons can be transferred to oxygen. Limited in vitro proteolysis with papain resulted in the formation of several protein fragments that are active with DCIP but not with cytochrome c. Such a flavin-containing fragment, with a mass of 75 kDa and a pI of 5.1 and lacking the heme domain, was isolated and partially characterized.

scholarly journals Mycelial compatibility and aggressiveness of Sclerotinia sclerotiorum isolates from Brazil and the United States

2014 ◽  
Vol 49 (4) ◽  
pp. 265-272 ◽  
Author(s):  
Lucimara Junko Koga ◽  
Charles Roger Bowen ◽  
Claudia Vieira Godoy ◽  
Maria Cristina Neves de Oliveira ◽  
Glen Lee Hartman
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Sclerotinia Sclerotiorum ◽  
Country Of Origin ◽  
The United States ◽  
Soybean Field ◽  
Soybean Cultivars ◽  
Mycelial Compatibility ◽  
The Usa ◽  
Midwest Region

The objective of this work was to evaluate the genetic diversity among Sclerotinia sclerotiorum isolates from Brazil and the USA, assess their aggressiveness variability, and verify the existence of an isolate-cultivar interaction. Isolate variability was determined by mycelial compatibility grouping (MCG), and isolate aggressiveness by cut-stem inoculations of soybean cultivars. Two experiments for MCGs and two for aggressiveness were conducted with two sets of isolates. The first set included nine isolates from the same soybean field in Brazil and nine from the Midwest region of the USA. The second set included 16 isolates from several regions of Brazil and one from the USA. In the first set, 18 isolates formed 12 different MCGs. In the second set, 81% of the isolates from Brazil grouped into a single MCG. No common MCGs were observed among isolates from Brazil and the USA. The isolates showed aggressiveness differences in the first set, but not in the second. Although aggressiveness differed in the first set, soybean cultivars and isolates did not interact significantly. Cultivar rank remained the same, regardless of the genetic diversity, aggressiveness difference, and region or country of origin of the isolate. Results from screening of soybean cultivars, performed by the cut-stem method in the USA, can be used as reference for researchers in Brazil.

scholarly journals First Report of Root and Collar Rot by Sclerotium rolfsii on Apple Trees in Italy

Plant Disease ◽  
1999 ◽  
Vol 83 (7) ◽  
pp. 695-695
Author(s):  
L. Corazza ◽  
A. Belisario ◽  
E. Forti
Keyword(s):  
Apple Tree ◽  
Sclerotium Rolfsii ◽  
Apple Trees ◽  
Collar Rot ◽  
Athelia Rolfsii ◽  
Leaf Chlorosis ◽  
General Decline ◽  
Summer Temperatures ◽  
Ground Plate ◽  
Mycelial Strands

Sclerotium rolfsii Sacc. (teleomorph Athelia rolfsii (Curzi) Tu & Kimbrough) is a polyphagous, soilborne plant pathogen. In summer 1998, a sudden death of 2-year-old apple trees (Malus domestica Borkh.) cv. Royal Gala grafted on M9 rootstock was observed in an orchard near Rome, Italy. Symptoms were stunted vegetation, leaf chlorosis, and root and collar rot. A fungus identified as S. rolfsii was observed producing sclerotia and whitish mycelial strands on root and collar bark. Isolations from roots and at the margin of subcortical necrosis on the collar consistently yielded S. rolfsii colonies on potato dextrose agar (PDA); sclerotia developed within 7 days. Koch's postulates were fulfilled by inoculating 10 1-year-old apple tree cv. M9 rootstocks, grown in 3.5-liter pots, with an S. rolfsii isolate grown for 1 week on PDA at 25°C. One ground plate per plant was used, placed around collar and main roots. Five control plants were treated with PDA only. Rootstocks were kept in the greenhouse at 26 ± 2°C. Within 2 months, 70% of inoculated plants died, with marked necrosis girdling the collar. The other inoculated plants showed a general decline, with widespread necrosis on collars and main roots. Control plants remained healthy. S. rolfsii was reisolated from collars and roots of symptomatic plants. S. rolfsii has been recorded on apple trees in the U.S., India, China, and Israel. In Italy, it is destructive on several crops, and was recently recorded on walnut (1). This first outbreak of S. rolfsii on apple in Italy may have been favored by exceptionally warm late spring and summer temperatures. Reference: (1) A. Belisario and L. Corazza. Plant Dis. 80:824, 1996.

Sign in / Sign up

Export Citation Format

Share Document