scholarly journals Characterization of Rhizoctonia solani Associated with Black Scurf in Cyprus

Plant Disease ◽  
2016 ◽  
Vol 100 (8) ◽  
pp. 1591-1598
Author(s):  
Loukas Kanetis ◽  
Dimitris Tsimouris ◽  
Michalakis Christoforou
Keyword(s):  
Rhizoctonia Solani ◽  
Internal Transcribed Spacer ◽  
Black Scurf ◽  
Crop Rotations ◽  
Potato Tubers ◽  
Biological Aspects ◽  
Its1 And Its2 ◽  
Comprehensive Study

During 2011, 96 sclerotial isolates of Rhizoctonia solani were collected from potato tubers from all main potato-cultivating regions of Cyprus. All isolates were found to be multinucleate. Characterization of anastomosis groups (AG) based on hyphal anastomosis reactions showed that 91 isolates belonged to AG3 and 5 to AG4. Sequence analysis of the internal transcribed spacer (ITS) regions (ITS1 and ITS2) of ribosomal DNA (rDNA) of 68 isolates confirmed the prevalence of AG3. In addition, phylogenetic analysis found that AG3 isolates were of the potato type, distinctly separated from the AG3 tobacco type, while AG4 isolates were separated into two different subgroups (HGI and HGII). Temperature studies showed that isolates belonging to both AG4 subgroups had significantly higher optimum growth temperatures compared with AG3. In vitro sensitivities to the fungicide pencycuron, in terms of concentrations where 50% growth inhibition was observed, ranged from 0.012 to 0.222 μg/ml. Pathogenicity and aggressiveness of the isolates was determined on ‘Annabelle’ potato sprouts and seedlings of a number of selected hosts, based on crop rotations followed in Cyprus. The majority of the isolates were pathogenic to potato sprouts, with disease severity (DS) values ranging from 0 to 88%. Mean DS values were statistically different among AG and subgroups, with AG4-HGI (69.25%) and AG4-HGII (3.12%) being the most and least aggressive, respectively. However, AG4-HGII isolates were the most aggressive in all rotational hosts tested, while AG3 isolates were the least aggressive. More specifically, the highest DS levels by AG4-HGI were recorded to barley, by AG4-HGII to lettuce and melon, and by AG3 isolates to vetch. This is the first comprehensive study to elucidate the AG composition, pathogenicity and other biological aspects of R. solani isolates associated with potato black scurf in Cyprus.

scholarly journals Rhizoctonia solani Anastomosis Group 3 is Predominant in Potato Tubers in Poland

Plant Disease ◽  
2013 ◽  
Vol 97 (9) ◽  
pp. 1245-1245 ◽  
Author(s):  
J. W. Woodhall ◽  
B. Lutomirska ◽  
J. C. Peters ◽  
P. S. Wharton
Keyword(s):  
Rhizoctonia Solani ◽  
Tap Water ◽  
Anastomosis Group ◽  
Black Scurf ◽  
Crop Rotations ◽  
Potato Tubers ◽  
Hyphal Fusion ◽  
Group 3 ◽  
Plant Pathol ◽  
Potato Crops

Rhizoctonia solani is a species complex of 13 related but genetically distinct anastomosis groups (AGs). In potato, R. solani can infect the stems, stolons, and roots, resulting in quantitative losses. It can also cause qualitative losses through blemishes occurring on progeny tubers, such as black scurf and elephant hide (corky cracking). Knowledge of the AG in local populations is important because they differ in host range, fungicide sensitivity, and disease severity (2). To determine the AGs present in Poland, 54 tuber samples displaying typical R. solani symptoms were taken from six different fields in 2011. The fields were representative of five different administrative regions of Poland and from at least 10 different varieties. Rhizoctonia was isolated from tubers by placing symptomatic material on to tap water agar amended with streptomycin and penicillin and after 2 to 3 days Rhizoctonia colonies were identified and hyphal tips of these transferred to potato dextrose agar. Rhizoctonia was successfully isolated from 48 tubers displaying black scurf and two tubers displaying elephant hide symptoms. DNA was extracted from Rhizoctonia cultures using a Wizard Food kit (Promega) and the AG was determined using specific real-time PCR assays (1). All Rhizoctonia isolates were determined to be AG3 and this was confirmed for 10 selected isolates by observing hyphal fusion with a known AG3 tester isolate (Rs08) as described previously (3). Pairings were also conducted amongst the 10 Polish isolates, C2 reactions were typically observed indicating numerous vegetative compatible groups are present. This study shows that AG3 is likely to be the predominant AG in potato tubers in Poland. This is similar to other studies in Europe, which have all determined that AG3 accounts for at least 92% of isolates from potato (2,3). AG2-1, 4, and 5 have also been found in tubers worldwide and climate and certain crop rotations can influence the presence of these other AGs in potato tubers (2). However, climate and crop rotations in Poland are similar to other parts of Europe so the predominance of AG3 is expected. AG3 was also isolated from elephant hide symptoms; however, it was more frequently isolated from sclerotia. The ability of AG3 to prolifically produce sclerotia and thereby survive on seed tubers may explain its predominance in potato crops (4). Therefore, studies focusing on the management of Rhizoctonia potato disease in Poland should consider AG3 in the first instance. References: (1) G. E. Budge et al. Plant Pathol. 58:1071, 2009. (2) L. Tsror. J. Phytopathol. 158:649, 2010. (3) J. W. Woodhall et al. Plant Pathol. 56:286, 2007. (4) J. W. Woodhall et al. Plant Pathol. 57:5, 2008.

scholarly journals Inhibition of Mycelial Growth of Rhizoctonia Solani by Chitosan in vitro and in vivo

2019 ◽  
Vol 13 (1) ◽  
pp. 156-161
Author(s):  
Sabah R. Mohammed ◽  
Elsayed M. Zeitar ◽  
Ivan D. Eskov
Keyword(s):  
Rhizoctonia Solani ◽  
Mycelial Growth ◽  
Phenylalanine Ammonia Lyase ◽  
Inhibitory Effect ◽  
Black Scurf ◽  
Potato Tubers ◽  
Antifungal Effect ◽  
Poisoned Food Technique

Objective: Evaluate the antifungal effect of chitosan against Rhizoctonia solani in vitro and the possible mechanisms of its induced activity in potato tubers to control black scurf disease. Methods: The in vitro influence of chitosan at different concentrations on mycelial growth of R. solani was tested by using the poisoned food technique in PDA medium. The effect of these concentrations on the development of lesion diameters in tubers inoculated with R. solani mycelium was assayed for 30 days. The concentration that showed the greatest inhibitory effect on lesion diameters was tested to assess the induced activity of defense-related enzymes in the infected tubers. Results: In the poisoned food technique, chitosan at 1% completely inhibited the growth of R. solani mycelium. In vivo tests showed that chitosan treatment at 0.5% effectively controlled the black scurf in tubers inoculated with R. solani mycelium. Chitosan increased the activities of defense-related enzymes such as Peroxidase (POD), Polyphenol Oxidase (PPO) and Phenylalanine Ammonia-lyase (PAL) in treated tubers of tested cultivars. Conclusion: This work demonstrated that chitosan directly inhibited the growth of R. solani, and potentially elicited defense reaction in potato tubers.

scholarly journals First Report of Black Scurf Caused by Rhizoctonia solani AG-3 on Potato Tubers in Mauritius

Plant Disease ◽  
2021 ◽  
Vol 105 (1) ◽  
pp. 213
Author(s):  
S. D. Takooree ◽  
H. Neetoo ◽  
V. M. Ranghoo-Sanmukhiya ◽  
S. Hardowar ◽  
J. E. van der Waals ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Black Scurf ◽  
Potato Tubers ◽  
First Report

scholarly journals In vitro evaluation of fungicidal responses on the growth of pathogenic Rhizoctonia solani Kuhn, antagonistic binucleate Rhizoctonia and Trichoderma harzianum Rifai

1970 ◽  
Vol 39 (1) ◽  
pp. 107-110
Author(s):  
Md Maniruzzaman Khandaker ◽  
Md Khurshed Alam Bhuiyan ◽  
Abul Khair
Keyword(s):  
Boric Acid ◽  
Rhizoctonia Solani ◽  
Key Words ◽  
Trichoderma Harzianum ◽  
Stem Canker ◽  
Black Scurf ◽  
Binucleate Rhizoctonia ◽  
Crop Fields ◽  
Potato Plants

Two pathogenic isolates of Rhizoctonia solani Kuhn causing stem canker/black scurf disease of potato plants and four antagonist isolates, two of binucleate Rhizoctonia and two of Trichoderma harzianum Rifai were isolated from crop fields and evaluated in vitro for their fungicidal responses against eight fungicides. Vitavax was effective in inhibiting the growth of R. solani and binucleate Rhizoctonia but it did not inhibit the growth of T. harzianum at 100 ppm concentration. Terraclor Super X, Dithane M 45 and Boric acid are the fungicides which at 100 ppm concentration did not inhibit the growth of antagonist isolates of T. harzianum and binucleate Rhizoctonia but inhibited the growth of isolates of R. solani to some extent. The in vitro findings suggest that any one of these three fungicides along with antagonist isolates of binucleate Rhizoctonia and T. harzianum can be used as biocontrol agents to reduce soil borne inocula of R. solani. Key words: Rhizoctonia solani; Binucleate; Trichoderma harzianum; Fungicide DOI: 10.3329/bjb.v39i1.5534Bangladesh J. Bot. 39(1): 107-110, 2010 (June)

Characterization of Cell Wall Degrading Enzymes of Rhizoctonia solani AG-3 from Tobacco Target Spot

2014 ◽  
Vol 1010-1012 ◽  
pp. 1161-1164
Author(s):  
Yan Qin Zhao ◽  
Yuan Hua Wu ◽  
Xiu Xiang Zhao ◽  
Meng Nan An ◽  
Jian Guang Chen ◽  
...  
Keyword(s):  
Cell Wall ◽  
Rhizoctonia Solani ◽  
Cell Wall Degrading Enzymes ◽  
Degrading Enzymes ◽  
Yield And Quality ◽  
Target Spot ◽  
Causal Pathogen

Rhizoctonia solaniKühn is a causal pathogen responsible for many types of plant disease worldwide and a major soilborne fungal pathogen that severely impairs yield and quality of tobacco worldwide. Activities, pathogenicity of the cell wall-degrading enzymes produced by theRhizoctoniasolanifrom tobacco target spot disease both in liquid medium and in tobacco tissue were studied. The result showed thatR.solanifrom tobacco can produce pectinase and cellulase both in vitro and vivo, and the activity of PG and PMG was the highest in vitro. The activity of Cx and β-glucosidase was the highest in vivo, and enzyme production ability of strong pathogenicity strains is stronger than the weak pathogenicity strains in vitro.

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 Identification and characterization ofDaldinia eschscholtziiisolated from skin scrapings, nails, and blood

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2637 ◽  
Author(s):  
Kee Peng Ng ◽  
Chai Ling Chan ◽  
Su Mei Yew ◽  
Siok Koon Yeo ◽  
Yue Fen Toh ◽  
...  
Keyword(s):  
Internal Transcribed Spacer ◽  
Woody Plants ◽  
Antimicrobial Agents ◽  
Inhibitory Concentration ◽  
Antifungal Susceptibility ◽  
Future Studies ◽  
Identification And Characterization ◽  
Morphological And Molecular Characterization

BackgroundDaldinia eschscholtziiis a filamentous wood-inhabiting endophyte commonly found in woody plants. Here, we report the identification and characterization of nineD. eschscholtziiisolates from skin scrapings, nail clippings, and blood.MethodsThe nine isolates were identified based on colony morphology, light microscopy, and internal transcribed spacer (ITS)-based phylogeny.In vitroantifungal susceptibility of the fungal isolates was evaluated by the Etest to determine the minimum inhibitory concentration (MIC).ResultsThe nine isolates examined were confirmed asD. eschscholtzii. They exhibited typical features ofDaldiniasp. on Sabouraud Dextrose Agar, with white felty colonies and black-gray coloration on the reverse side. Septate hyphae, branching conidiophore with conidiogenous cells budding from its terminus, and nodulisporium-like conidiophores were observed under the microscope. Phylogenetic analysis revealed that the nine isolates were clustered within theD. eschscholtziispecies complex. All the isolates exhibited low MICs against azole agents (voriconazole, posaconazole, itraconazole, and ketoconazole), as well as amphotericin B, with MIC of less than 1 µg/ml.DiscussionEarly and definitive identification ofD. eschscholtziiis vital to reducing misuse of antimicrobial agents. Detailed morphological and molecular characterization as well as antifungal profiling ofD. eschscholtziiprovide the basis for future studies on its biology, pathogenicity, and medicinal potential.

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