scholarly journals A New Subgroup of Rhizoctonia AG-D, AG-D III, Obtained from Japanese Zoysia Grass Exhibiting Symptoms of a New Disease

Plant Disease ◽  
2006 ◽  
Vol 90 (11) ◽  
pp. 1389-1394 ◽  
Author(s):  
Toshihiro Hayakawa ◽  
Takeshi Toda ◽  
Qu Ping ◽  
Joseph M. Mghalu ◽  
Shigeharu Yaguchi ◽  
...  

Isolates of an unidentified Rhizoctonia sp. (UN isolates) were obtained from Japanese zoysia grass (Zoysia japonica Steud) that exhibited symptoms of a new sheath rot disease. UN isolates were binucleate and showed hyphal fusion with tester isolates of Rhizoctonia anastomosis group (AG)-D. Those isolates were compared with isolates of subgroups I and II of Rhizoctonia AG-D based on cultural morphology, hyphal growth rate at different temperatures, anastomosis frequency, pathogenicity, and sequence analysis of the internal transcribed spacer (ITS) region of ribosomal DNA genes (rDNA-ITS region). The mycelial color of UN isolates was light yellow which differs from AG-D I but is similar to AG-D II. Sclerotia of UN isolates were dark brown in color and larger in size (1 to 3 mm in diameter) than those of AG-D subgroup I (1 mm in diameter), whereas isolates of AG-D II produced white mycelial clamps 4 to 5 mm in size. Hyphal growth rate of UN isolates was slower than that of two AG-D subgroups at several temperatures, especially 25°C. In pathogenicity tests on Japanese zoysia grass, UN isolates showed moderate disease severity and lower pathogenicity than isolates of AG-D subgroups I and II. Sequences of the rDNA-ITS region within UN isolates were almost homologous, but had lower homology with subgroups AG-D I or II. Phylogenetic trees constructed using ITS sequences showed that UN isolates formed an individual cluster that differed from the clusters of the two subgroups. We propose that UN isolates are a new subgroup of Rhizoctonia AG-D, subgroup III, and the name of the disease is “spring-rot” on Japanese zoysia grass.

2005 ◽  
Vol 95 (7) ◽  
pp. 784-792 ◽  
Author(s):  
Mitsuro Hyakumachi ◽  
Achmadi Priyatmojo ◽  
Mayumi Kubota ◽  
Hirokazu Fukui

Root and stem rot of cut-flower roses (Rosa spp.) was observed in commercial glasshouse-grown roses in 10 prefectures of Japan from 1998 through 2001. Binucleate-like Rhizoctonia spp. were isolated mainly from the disease plants. In all, 670 isolates were divided into two types based on cultural appearance; 168 isolates of light brown to brown type and 502 isolates of whitish type. A hyphal anastomosis reaction using representative isolates from each type revealed that the light brown to brown type belonged to anastomosis group G (AG-G), whereas the whitish type (AG-CUT) failed to anastomose with tester strains of binucleate Rhizoctonia AG-A through AG-S. Neither isolates of AG-G nor AG-CUT anastomosed with tester strains of a previously reported unknown AG (AG-MIN) of binucleate Rhizoctonia spp. collected from miniature roses. In pathogenicity tests, randomly selected isolates of the three groups caused root and stem rot on cut-flower and miniature roses. To differentiate AG-CUT and AG-MIN from known AGs of binucleate Rhizoctonia spp., restriction fragment length polymorphism (RFLP) and sequence analyses of a ribosomal (r)DNA internal transcribed spacer (ITS) region were conducted. Among the eight restriction enzymes used, HaeIII produced DNA banding patterns for AG-CUT that differed from those of tester strains and AG-MIN. Additionally, restriction profiles of AG-MIN differed from those of all tester strains. AG-G isolates from cut-flower roses had the same RFLP pattern as the tester strains of AG-G. Based on the results of hyphal anastomosis and RFLP and sequence analysis of an rDNA-ITS region, we propose that AG-CUT be designated AG-T and AG-MIN be designated AG-U, two new AGs of binucleate Rhizoctonia spp. The phylogenetic tree based on the sequence data of the rDNA-ITS region showed that isolates of AG-MIN were in a distinct clade from other AGs, whereas isolates of AG-CUT were in the same clade as those of AG-A. More detailed phylogenetic analysis besides rDNA-ITS region might be necessary for AG classification of binucleate Rhizoctonia spp.


Plant Disease ◽  
2005 ◽  
Vol 89 (6) ◽  
pp. 536-542 ◽  
Author(s):  
Takeshi Toda ◽  
Tomoyuki Mushika ◽  
Toshihiro Hayakawa ◽  
Akemi Tanaka ◽  
Toshikazu Tani ◽  
...  

Isolates of an unidentified Rhizoctonia sp. (NP isolates), obtained from creeping bentgrass (Agrostis stolonifera var. palustris) in Japan that exhibited symptoms of a new disease, were compared with isolates of three varieties of Waitea circinata var. oryzae, var. zeae, and var. circinata. NP isolates also were compared with isolates of R. oryzae obtained from creeping bent-grass exhibiting white patch-like symptoms (RW isolates). The color and size of sclerotia, color of mycelia, and pigment deposition of NP isolates was similar to that of RW isolates and W. circinata var. circinata, but distinctly different from W. circinata var. oryzae and W. circinata var. zeae. The optimal temperature for hyphal growth of NP isolates, RW isolates, and W. circinata var. circinata was 28°C, and for W. circinata var. oryzae and W. circinata var. zeae was 30°C. Pathogenicity tests on creeping bentgrass showed that the severity of disease caused by NP isolates, RW isolates, and W. circinata var. circinata was greater than with W. circinata var. oryzae, but lower than with W. circinata var. zeae. No significant differences in symptom expression were apparent among NP isolates, RW isolates, and W. circinata var. circinata. A phylogenic tree, obtained using the results of random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR), showed that isolates of W. circinata var. oryzae and W. circinata var. zeae separated into individual clusters, while NP isolates, RW isolates, and W. circinata var. circinata clustered together. The lengths of the rDNA internal transcribed spacer (ITS) region of NP isolates, RW isolates, and W. circinata var. circinata were identical but smaller than those of W. circinata var. oryzae and W. circinata var. zeae. Restriction fragment length polymorphism (RFLP) analysis of the rDNA-ITS region, using three enzymes (HapII, HinfI, and MboI), also showed that NP isolates were the same as RW isolates and W. circinata var. circinata, but different from W. circinata var. oryzae and W. circinata var. zeae. Based on these results, the NP isolates causing a new disease on bentgrass are W. circinata var. circinata, and that RW isolates are also W. circinata var. circinata but not R. oryzae. We propose that the name of the disease on creeping bentgrass caused by W. circinata var. circinata is brown ring patch.


2020 ◽  
Vol 46 (4) ◽  
pp. 289-298
Author(s):  
Maria Aurea Saboya Chiaradia Picarelli ◽  
Flavia Rodrigues Alves Patricio ◽  
Ricardo Harakava ◽  
Eliana Borges Rivas ◽  
Addolorata Colariccio

ABSTRACT The use of cultivated grasses in Brazil has grown by 40% between 2010 and 2015, and the species Zoysia japonica Steud, especially the cultivar ‘Esmeralda’, corresponds to 81% of the grass market in the country. The most important disease affecting zoysia grass, known as large patch, is caused by Rhizoctonia solani and occurs in the Brazilian lawns particularly during winter months. The aim of this study was to contribute to the identification and characterization of the anastomosis group of R. solani isolates from lesions typical of large patch collected from ‘Esmeralda’ grass at gardens and golf courses in the states of São Paulo and Bahia, Brazil. All 12 obtained isolates presented dark-brown colonies with aerial mycelial growth, multinucleated hyphae and absence of concentric zonation or sclerotia, and showed their greatest mycelial growth rate at 25°C. In pathogenicity experiments, except three out of R. solani isolates, reduced the growth of zoysia grass. Based on the analysis of sequences of the rDNA-ITS region, the isolates clustered with reference isolates of the anastomosis group AG 2-2 LP. Phylogenetic inference showed that the Brazilian isolates are grouped into two clades that shared the same common ancestral with 96% bootstrap. One of the clades includes only Brazilian isolates while the other one also includes American and Japanese R. solani isolates AG 2-2 LP. This is the first report and characterization of R. solani AG 2-2 LP in zoysiagrass in Brazil.


2021 ◽  
Vol 285 ◽  
pp. 05020
Author(s):  
Elena Lobodina ◽  
Ivan Suprun ◽  
Natalya Ageeva ◽  
Ekaterina Al-Nakib

The studies present the results of morphological, cultural and genetic analysis of the ITS1-ITS4 region of the autochthonous yeast strains genome by using the HaeIII restriction enzyme. On the red and white grapes varieties, based on the morphology of the cells, autochthonous strains belonging to the genus Saccharomyces prevail – 83.3%, what is confirmed by genetic analysis of rDNA ITS region. Restriction analysis showed that all strains of the genus Saccharomyces belong to the species Saccharomyces cerevisiae / S. paradoxus. The percentage of Saccharomyces isolated on the Pervenets Magaracha variety is 86.7%, Krasnostop Anapsky - 80%. The non-Saccharomyces yeast had a product size of 750 bp, presumably of the species Hanseniaspora uvarum.


Horticulturae ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 87
Author(s):  
Kumpei Shiragaki ◽  
Shuji Yokoi ◽  
Takahiro Tezuka

The genus Capsicum is comprised of 5 domesticated and more than 30 wild species. The region of nuclear ribosomal DNA internal transcribed spacers (rDNA-ITS) has widely been used for species identification, but has rarely been used in Capsicum. In this study, the evaluation of genetic diversity and a phylogenetic analysis were conducted using rDNA-ITS of 28 Capsicum accessions, including five domesticated and two wild species. We surveyed six conventional keys of domesticated species and another five traits in Capsicum accessions. Specific morphological characteristics were found in C. annuum, C. baccatum, and C.pubescens. Three subclones of each accession were sequenced, and rDNA-ITS polymorphisms were detected in all accessions excluding C. annuum, suggesting that incomplete concerted evolution occurred in rDNA-ITS of Capsicum. The genetic diversity was evaluated using nucleotide polymorphism and diversity. C. annuum had the lowest genetic diversity of all species in this study. The phylogenetic tree formed a species-specific clade for C. annuum, C. baccatum, and C. pubescens. The C. chinense clade existed in the C. frutescens clade, implying that it was a cultivated variant of C. frutescens. C. chacoense likely belonged to the C. baccatum complex according to its morphologic and genetic features. This study indicated that the rDNA-ITS region can be used for simple identification of domesticated Capsicum species.


2016 ◽  
Vol 10 (1s) ◽  
pp. 35
Author(s):  
Jordan Merkuri ◽  
Stefania Mirela Mang ◽  
Ippolito Camele ◽  
Magdalena Cara ◽  
Gian Luigi Rana

Basidiomata of a wild mushroom macroscopically recognised as <em>Pleurotus ostreatus</em> were observed on an oak trunk in a mixed wood of northern Albania. Pure cultures of the fungus were then obtained on potato-dextrose-agar medium. Molecular analyses of genomic DNA of the fungus confirmed its identification. The rDNA ITS region nucleotide sequence of the studied <em>Pleurotacea</em> matched at 99% those of two <em>P. ostreatus</em> strains already present in NCBI GenBank database. The rDNA ITS nucelotide sequences of two pure cultures of the Albanian <em>P. ostreatus</em> were deposited in EMBL database under the accession numbers LN849458 and LN849459. One of the fungus isolates was subsequently cultivated under protected and semi-natural conditions. Productivity and biological efficiency of the Albanian <em>P. ostreatus</em> ranged from about 10% to 16% and from 33 to 53.33%, respectively. This seems to be the first report on the artificial cultivation of <em>P. ostreatus</em> in Albania and could have, in the next future, a high economic impact on development and diffusion of this important edible mushroom over the country.


Plant Disease ◽  
2010 ◽  
Vol 94 (5) ◽  
pp. 563-569 ◽  
Author(s):  
L. D. Maccarone ◽  
M. J. Barbetti ◽  
K. Sivasithamparam ◽  
R. A. C. Jones

Lettuce plants showing symptoms of lettuce big-vein disease were collected from fields in the Perth Metropolitan region of southwest Australia. When root extracts from each plant were tested by polymerase chain reaction (PCR) using primers specific to the rDNA internal transcribed spacer (ITS) region of Olpidium brassicae and O. virulentus, only O. virulentus was detected in each of them. The nucleotide sequences of the complete rDNA ITS regions of isolates from five of the root samples and 10 isolates of O. virulentus from Europe and Japan showed 97.9 to 100% identities. However, with the six O. brassicae isolates, their identities were only 76.9 to 79.4%. On phylogenetic analysis of the complete rDNA-ITS region sequences of the five Australian isolates and 10 others, the Australian isolates fitted within two clades of O. virulentus (I and II), and within clade I into two of its four subclades (Ia and Id). Japanese isolates had greatest sequence diversity fitting into both clades and into all of clade I subclades except Ib, while European isolates were restricted to subclades Ib and Id. When the partial rDNA-ITS region sequences of two additional southwest Australian isolates, four from Europe, and four from the Americas were included in the analyses, the Australian isolates were within O. virulentus subclades Ia and Id, the European isolates within subclade Ic, and the American isolates within subclades Ia and Ib. These findings suggest that there may have been at least three separate introductions of O. virulentus into the isolated Australian continent since plant cultivation was introduced following its colonization by Europeans. They also have implications regarding numbers of different introductions to other isolated regions. Lettuce big-vein associated virus and Mirafiori lettuce big-vein virus were both detected when symptomatic lettuce leaf tissue samples corresponding to the root samples from southwest Australia were tested using virus-specific primers in reverse transcription–PCR, so presence of both viruses was associated with O. virulentus occurrence.


1996 ◽  
Vol 13 (9) ◽  
pp. 1276-1295 ◽  
Author(s):  
M. A. Hershkovitz ◽  
L. A. Lewis

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