Phylogenetic Subgrouping of Rhizoctonia solani AG 2 Isolates Based on Ribosomal ITS Sequences

Mycologia ◽  
1999 ◽  
Vol 91 (3) ◽  
pp. 459 ◽  
Author(s):  
Oscar Salazar ◽  
Johannes H. M. Schneider ◽  
Maria C. Julian ◽  
Jaap Keijer ◽  
Victor Rubio
Keyword(s):  
Rhizoctonia Solani ◽  
Its Sequences

scholarly journals First Report of Rhizoctonia solani AG-2-2 IIIB Causing Foliar Blight on Bletilla striata in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Hao Zhou ◽  
Shuang-Feng Yang ◽  
Shao-Mei Wang ◽  
Ke Yao ◽  
Xiao-Yu Ye ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Its Sequences ◽  
Nucleotide Sequence Analysis ◽  
Peat Moss ◽  
Its2 Region ◽  
Post Inoculation ◽  
Bletilla Striata ◽  
First Report ◽  
Foliar Blight ◽  
Initial Symptoms

Bletilla striata (Thunb.) Rchb. f. (Orchidaceae), a perennial plant, is a traditional Chinese herb (known as baiji) used to treat hemorrhage, scalding injuries, gastric ulcers, pulmonary diseases, and inflammation (Zu et al. 2019). In May 2019, foliar blight symptoms were observed on approximately 25% of B. striata (cv. Guiji No.1) plants in three plantations (∼4.5 hectares in total) in Ziyuan County, Guangxi Province, China. Initial symptoms were light brown, irregular, water-soaked spots on the plant leaves. Several spots often merged, forming large, irregular, lesions that extended onto the stem after a week and led to leaf abscission, and even plant death. To determine the causal agent, 5-mm squares cut from the margin of 6 infected leaves were surface disinfected in 1% sodium hypochlorite solution for 2 min, rinsed three times with sterile distilled water, plated on potato dextrose agar (PDA), and incubated at 28°C (12-h light-dark cycle) for 3 days. The emerging hyphal tip of a single mycelium was transferred to PDA to obtain pure cultures of the isolates. Twenty isolates were obtained, and 10 isolates (50%) were initially white before turning light brown (∼4 days). Septate hyphae were 4.29 to 10.75 μm (average 6.42 μm) in diameter and branched at right angles with a constriction at the origin of the branch point. Staining with 1% safranin O and 3% KOH solution (Bandoni 1979) revealed multinucleated cells (3 to 9 nuclei per cell, n = 142). This morphology was typical of Rhizoctonia solani Kühn (Meyer et al. 1990). For species confirmation by molecular identification, three isolates (BJ101.6, BJ101.11, and BJ102.2) were cultured on PDA for 4 days, then DNA was extracted from the mycelium using the CTAB method (Guo et al. 2000), and the ribosomal ITS1-5.8S-ITS2 region was amplified by PCR using the universal fungal primers ITS1 and ITS4 (White et al. 1990). Internal transcribed spacer (ITS) sequences of strains BJ101.6, BJ101.11, and BJ102 (deposited in GenBank under accession nos MT406271, MT892815, and MT892814, respectively) had over 99% similarity with those of R. solani AG-2-2 IIIB in GenBank (accession nos JX913810 and AB054858) (Carling et al. 2002; Hong et al. 2012). Phylogenetic analysis using ITS sequences showed that the isolates clustered monophyletically with strains of R. solani AG-2-2 IIIB. The AG of the isolates was confirmed by their ability to grow well on PDA at 35°C, which separates AG-2-2 IIIB from AG-2-2 IV (Inokuti et al. 2019). Based on morphological characteristics and nucleotide sequence analysis, the isolates were identified as R. solani AG-2-2 IIIB. Pathogenicity was tested using 1.5-year-old B. striata (cv. Guiji No.1) plants grown in a perlite and peat moss mixture (1:3) in 7-cm pots. Healthy leaves on plants were inoculated with an aqueous suspension (approximately 1 × 105 hyphal fragments/mL, 100 μL) prepared from cultures of strains BJ101.6, BJ101.11, and BJ102.2, each isolate was inoculated onto three plants; three other plants with sterile water served as controls. All plants were enclosed in transparent plastic bags and incubated in a greenhouse at 28°C for 14 days (12-h photoperiod). Three days post-inoculation, leaves exposed to the mycelial fragments had symptoms similar to those originally observed in the field. No symptoms were detected on control plants. Experiments were replicated three times with similar results. To fulfill Koch’s postulates, R. solani AG-2-2 IIIB was re-isolated on PDA from symptomatic leaves and confirmed by sequencing, whereas no fungus was isolated from the control plants. To our knowledge, this is the first report of R. solani AG-2-2 IIIB causing foliar blight on B. striata in China, and these findings will be useful for further control strategies and research.

Phylogenetic grouping of cultural types of Rhizoctonia solani AG 2–2 based on ribosomal ITS sequences

Mycologia ◽  
2000 ◽  
Vol 92 (3) ◽  
pp. 505-509
Author(s):  
Oscar Salazar ◽  
María C. Julián ◽  
Mitsuro Hyakumachi ◽  
Victor Rubio
Keyword(s):  
Rhizoctonia Solani ◽  
Its Sequences ◽  
Phylogenetic Grouping ◽  
Cultural Types

Typing of anastomosis groups ofRhizoctonia solaniby restriction analysis of ribosomal DNA

2003 ◽  
Vol 49 (9) ◽  
pp. 556-568 ◽  
Author(s):  
Cécile Guillemaut ◽  
Véronique Edel-Hermann ◽  
Pierre Camporota ◽  
Claude Alabouvette ◽  
Marc Richard-Molard ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Rhizoctonia Solani ◽  
Ribosomal Dna ◽  
Restriction Analysis ◽  
Anastomosis Group ◽  
Internal Transcribed Spacers ◽  
Its Sequences ◽  
Typing Method ◽  
Rflp Type ◽  
Pcr Rflp

A method based on restriction analysis of polymerase chain reaction (PCR)-amplified ribosomal DNA was developed for the rapid characterization of large populations of Rhizoctonia solani at the anastomosis group (AG) level. The restriction maps of the internal transcribed spacers (ITS) sequences were compared for 219 isolates of R. solani belonging to AG-1 to AG-12 and AG-BI, representing diverse geographic and host range origins. Four discriminant restriction enzymes (MseI, AvaII, HincII, and MunI) resolved 40 restriction fragment length polymorphism (RFLP) types among the 219 ITS sequences of R. solani. Each RFLP type could be assigned to a single AG except for two RFLP types, which were common to two AG. A fifth enzyme allowed the discrimination of AG-6 and AG-12. In addition, the combination of four enzymes allowed the discrimination of subsets within AG-1, AG-2, AG-3, and AG-4. The efficiency of the typing method was confirmed by analyzing PCR-amplified ITS sequences of 30 reference strains. Furthermore, the PCR–RFLP method was used to characterize at the AG level 307 isolates of R. solani originating from ten sugar beet fields exhibiting patches of diseased plants in France. The PCR-based procedure described in this paper provides a rapid method for AG typing in R. solani.Key words: Rhizoctonia solani, anastomosis group, PCR–RFLP, ITS, identification, sugar beet.

Phylogenetic Grouping of Cultural Types of Rhizoctonia solani AG 2-2 Based on Ribosomal ITS Sequences

Mycologia ◽  
2000 ◽  
Vol 92 (3) ◽  
pp. 505 ◽  
Author(s):  
Oscar Salazar ◽  
Maria C. Julian ◽  
Mitsuro Hyakumachi ◽  
Victor Rubio
Keyword(s):  
Rhizoctonia Solani ◽  
Its Sequences ◽  
Phylogenetic Grouping ◽  
Cultural Types

Comparison of rDNA-ITS Sequences between Potato and Tobacco Strains in Rhizoctonia solani AG-3

2000 ◽  
Vol 66 (1) ◽  
pp. 2-11 ◽  
Author(s):  
Shiro KUNINAGA ◽  
Donald E CARLING ◽  
Toru TAKEUCHI ◽  
Ryozo YOKOSAWA
Keyword(s):  
Rhizoctonia Solani ◽  
Its Sequences ◽  
Rdna Its ◽  
Rdna Its Sequences

Phylogenetic subgrouping of Rhizoctonia solani AG 2 isolates based on ribosomal ITS sequences

Mycologia ◽  
1999 ◽  
Vol 91 (3) ◽  
pp. 459-467 ◽  
Author(s):  
Oscar Salazar ◽  
Johannes H. M. Schneider ◽  
María C. Julián ◽  
Jaap Keijer ◽  
Victor Rubio
Keyword(s):  
Rhizoctonia Solani ◽  
Its Sequences

scholarly journals Hyphal Anastomosis Reactions, rDNA-Internal Transcribed Spacer Sequences, and Virulence Levels Among Subsets of Rhizoctonia solani Anastomosis Group-2 (AG-2) and AG-BI

2002 ◽  
Vol 92 (1) ◽  
pp. 43-50 ◽  
Author(s):  
D. E. Carling ◽  
S. Kuninaga ◽  
K. A. Brainard
Keyword(s):  
Rhizoctonia Solani ◽  
Internal Transcribed Spacer ◽  
Anastomosis Group ◽  
Its Sequences ◽  
Rdna Its ◽  
Rdna Its Sequences ◽  
Internal Transcribed Spacer Sequences ◽  
Hyphal Anastomosis ◽  
Group 2 ◽  
Group Specific Primer

Hyphal anastomosis reactions, rDNA-internal transcribed spacer (ITS) sequences, and virulence of isolates representing Rhizoctonia solani AG-BI and six subsets of anastomosis group (AG)-2 (-2-1, -2-2 IIIB, -2-2 IV, -2-2 LP, -2-3, and -2-4) were compared. AG-2-4 is a subset described for the first time in this report. Anastomosis reactions within AG-BI and the listed subsets of AG-2 were generally strong but, between subsets, ranged from strong to a very weak “bridging” -type reaction. Anastomosis reaction alone generally did not provide adequate evidence for placement of an isolate into a subset of AG-2. Anastomosis reactions between AG-BI and the original subsets of AG-2 (-2-1 and -2-2) are very strong; for this reason, we propose that it be included as a subset of AG-2 (designation AG-2 BI). Subsets -2-3 and -2-4 show very weak bridging-type anastomosis reactions with all other subsets of AG-2 and thus may be candidates for independent AG status. Grouping within AG-2 based on rDNA-ITS sequences was consistent with the abovementioned subsets. However, grouping based on virulence as measured herein does not conform to established grouping patterns within AG-2 and does not seem useful as a group-defining criterion. A broad range of damage was observed among members of the most virulent subsets (-2-1, -2-2 IIIB, -2-2 IV, and -2-4), whereas other subsets (-2 BI, -2-2 LP, and -2-3) were similar to one another in causing a minimal level of damage. Group-specific primer pairs for each of the seven subsets of AG-2 were designed based on the abovementioned rDNA-ITS sequences. Primer pairs proved dependable and subset specific in polymerase chain reaction amplifications of purified genomic DNA from 109 isolates of R. solani and two isolates of binucleate Rhizoctonia. These primers will provide a simple and useful method for subset-specific characterization within AG-2 if further critical evaluations confirm their specificity.

scholarly journals Summer Blight of White Clover (Trifolium repens) Caused by Rhizoctonia solani AG-1-IB in China

Plant Disease ◽  
2014 ◽  
Vol 98 (8) ◽  
pp. 1153-1153 ◽  
Author(s):  
Q. R. Bai ◽  
X. Y. Jiang ◽  
Y. Y. Xie ◽  
H. Y. Sun ◽  
J. Gao
Keyword(s):  
Rhizoctonia Solani ◽  
White Clover ◽  
Trifolium Repens ◽  
Morphological Characteristics ◽  
Its Region ◽  
Its Sequences ◽  
Northwestern China ◽  
Pathogenicity Test ◽  
Potted Plants ◽  
Plastic Bags

White clover (Trifolium repens), also known as Dutch clover (family Fabaceae), is an herbaceous, perennial plant, widely planted as pasture crop and occasionally used as lawn plant. From June to September in 2012 and 2013, approximately 5 to 8% of the plants as garden lawn were infected in the areas surveyed in Tonghua County, Jinlin Province. Ash green and water-soaked lesions appeared initially on the petiole and leaves. Subsequently, petioles collapsed with soft watery rot followed by collapse of leaves and eventually the entire plant. Aerial hyphae appeared on all the infected parts, followed by production of light brown to brown sclerotia. Seven isolates with the morphological characteristics of Rhizoctonia solani Kühn were isolated from symptomatic petioles and leaves which were surface disinfested in 70% alcohol for 30 s and 0.5% sodium hypochlorite for 1 min and plated on potato dextrose agar (PDA). Hyphal tips were transferred to a fresh plate of PDA and the cultures were examined for morphological characters microscopically. Mycelia of all isolates were branched at right angles with a septum near the branch and a slight constriction at the branch base. Hyphal cells were determined to be multinucleate when stained with 1% safranin O and 3% KOH solution (1) and examined at 400× magnification with a microscope. The internal transcribed spacer (ITS) region of the nuclear rDNA was amplified by using the primers ITS4 and ITS5 (2). The ITS sequences of isolates BSYJ14 (GenBank Accession No. HF678123), BSYJ31 (HF571130), BSYY21 (HF678126), and BSY22 (KC572140) exhibited 100% identity with that of R. solani AG 1-1B (AB122138 and HQ185364). ITS sequences of another three isolates, BSYJ11 (HF678122), BSYJ32 (HF678125), and BSYJ12 (HF678121) exhibited 99% identity with the ITS sequence of R. solani AG 1-1B. Pathogenicity tests were performed on healthy, potted T. repens. Five potted plants were inoculated at the base of the petiole with a 0.6-cm diameter mycelial plug from 3-day-old PDA cultures for each isolate, and the inoculation sites were covered with moistened sterile absorbent cotton. Another five potted plants were inoculated with sterile PDA plugs as controls. All plants in the experiments were covered with plastic bags and kept in a greenhouse at 20 to 25°C for 72 h, then the plastic bags were removed. After 5 to 7 days, the symptoms of watery rot were observed on petioles and leaves of all plants inoculated with these isolates, while control plants remained healthy. R. solani AG 1-IB was re-isolated from all plants inoculated with the isolates. The isolates were confirmed by morphological characteristics of the hyphae and hyphal fusions with the original isolates. The pathogenicity test was carried out twice with similar results. R. solani has been reported to cause root rot on T. pratense in northwestern China (4) and summer blight on T. pratense in Japan (3). To our knowledge, this is the first report of R. solani AG 1-IB causing summer blight on T. repens in China. References: (1) R. J. Bandoni. Mycologia 71:873, 1979. (2) D. E. L. Cooke et al. Mycol. Res. 101:667, 1997. (3) T. Tsukiboshi et al. Bull. Natl. Grassl. Res. Inst. 39:50, 1988. (4) W.-Y. Zhuang (ed.). Fungi of Northwestern China. Mycotaxon Ltd. Ithaca, NY, 2005.

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