scholarly journals Some characteristic of Rhizoctonia spp. in sharp eyespot of wheat

2014 ◽  
Vol 31 (2) ◽  
pp. 199-208 ◽  
Author(s):  
Helena Furgał-Węgrzycka ◽  
Jan Adamiak ◽  
Ewa Adamiak
Keyword(s):  
Growth Rate ◽  
Root Rot ◽  
Colony Growth ◽  
Anastomosis Group ◽  
Wheat Seedlings ◽  
Binucleate Cells ◽  
Ne Poland ◽  
Sharp Eyespot ◽  
Hyphal Anastomosis ◽  
H 20

Isolates of <i>Rhizttctonia</i> sp. with multinucleate and binucleate cells were obtained from sharp eyespot lesions on wheat culms in Olsztyn region. (NE Poland). These isolates were compared to isolates of AG-4 and GAG-1 testers with reference to cultural morphology of colony, growth rate, hyphal anastomosis and pathogenicity to wheat seedlings. The wheat binucleate isolates were similar in morphology of colonies and anastomosed with the <i>Ceratubasidium</i> anastomosis group GAG-1 tester isolates of <i>R. cerealis</i>. Growth rates on PDA ranged from 9 to 11 mm/24h for wheat isolates and from l to 11 mm/24 h for tester isolates GAG-1 of <i>R. cerealis</i>. The wheat multinucleate isolates were similar in morphology of colonies and anastomosed with <i>Rhizoctonia solani</i> Kühn group AG-4 tester isolate. <i>R. solani</i> AG-4 isolates were morphologically distinct from the <i>R. cerealis</i> isolates. These isolates on PDA were dark and grow rapidly (20-30 mm diam./24 h/20°C) and significantly contrasted with slowly growing white-creamy isolates of <i>R. cerealis</i> (GAG-1). Isolates of <i>R. solani</i> (AG-4) and <i>R. cerealis</i> (GAG-I) developed sharp eyespot lesions on culms and white head symptoms typical of the disease. None of the wheat isolates of <i>R. cerealis</i> (GAG-I) caused root-rot on wheat seedlings. In the present work the classification system of vegetative groups of <i>Rhizoctonia</i> spp. in present work is also discussed.

scholarly journals Rhizoctonia cerealis anastomosis group GAG-1, the common pathogen of wheat, barley and sugar beet

2014 ◽  
Vol 32 (1) ◽  
pp. 107-117
Author(s):  
Helena Furgał-Węgrzycka ◽  
Jan Adamiak ◽  
Ewa Adamiak
Keyword(s):  
Growth Rate ◽  
Sugar Beet ◽  
Crop Rotation ◽  
Root Rot ◽  
Anastomosis Group ◽  
Sharp Eyespot ◽  
Pathogenicity Tests ◽  
The Common ◽  
Hyphal Diameter ◽  
Rhizoctonia Cerealis

Isuluies of <i>Rhizoctonia cerealis</i> anastomosis group GAG-1 were obtained from sharp eyespot lesions on wheat and on barley culms and from diseased sugar beet seedlings. Isolates of <i>R. cerealis</i> were collected from a fields with crop rotation experiments: sugar beet-spring wheat-winter barley. In pathogenicity tests isolates of <i>R. cerealis</i> from sugar beet seedlings and from sharp eyespot lesions on wheat and barley were pathogenic to these crops. Isolates of <i>R. cerealis</i> from sharp eyespot lesions on wheat and barley caused severe damping-ofTof sugar beet. Isolates of <i>R. cerealis</i> from sugar beet seedlings also caused symptoms of sharp eyespot on wheat and barley. None of the wheat and barley isolates of <i>R. cerealis</i> tested caused root-rot on wheat or barley seedlings. Isolates of <i>R. cerealis</i> obtained from diseased plants of wheat, barley and sugar beet were similar in morphology of cultures and anastomosed with GAG-1 tester isolate. The relatinoship between anastomosis. colony characters, growth rate, hyphal diameter and pathogenicity of AG-4. AG-2-2 and AG-5 isolates obtained together with <i>R. cerealis</i> from diseased plants were also investigated.

scholarly journals Phytophthora mediterranea sp. nov., a New Species Closely Related to Phytophthora cinnamomi from Nursery Plants of Myrtus communis in Italy

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 682
Author(s):  
Carlo Bregant ◽  
Antonio A. Mulas ◽  
Giovanni Rossetto ◽  
Antonio Deidda ◽  
Lucia Maddau ◽  
...  
Keyword(s):  
New Species ◽  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Colony Growth ◽  
Phytophthora Species ◽  
Maximum Temperature ◽  
Pathogenicity Test ◽  
Forest Nurseries ◽  
Collar And Root Rot ◽  
A New Species

Monitoring surveys of Phytophthora related diseases in four forest nurseries in Italy revealed the occurrence of fourteen Phytophthora species to be associated with collar and root rot on fourteen plants typical of Mediterranean and alpine regions. In addition, a multilocus phylogeny analysis based on nuclear ITS and ß-tubulin and mitochondrial cox1 sequences, as well as micromorphological features, supported the description of a new species belonging to the phylogenetic clade 7c, Phytophthora mediterranea sp. nov. Phytophthora mediterranea was shown to be associated with collar and root rot symptoms on myrtle seedlings. Phylogenetically, P. mediterranea is closely related to P. cinnamomi but the two species differ in 87 nucleotides in the three studied DNA regions. Morphologically P. mediterranea can be easily distinguished from P. cinnamomi on the basis of its smaller sporangia, colony growth pattern and higher optimum and maximum temperature values. Data from the pathogenicity test showed that P. mediterranea has the potential to threaten the native Mediterranean maquis vegetation. Finally, the discovery of P. cinnamomi in alpine nurseries, confirms the progressive expansion of this species towards cold environments, probably driven by climate change.

Colony growth rate of encrusting marine bryozoans (Electra pilosa and Celleporella hyalina)

2001 ◽  
Vol 263 (1) ◽  
pp. 1-23 ◽  
Author(s):  
Pernille Hermansen ◽  
Poul S Larsen ◽  
Hans Ulrik Riisgård
Keyword(s):  
Growth Rate ◽  
Colony Growth ◽  
Electra Pilosa

scholarly journals Antagonistic Strain Bacillus amyloliquefaciens XZ34-1 for Controlling Bipolaris sorokiniana and Promoting Growth in Wheat

Pathogens ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1526
Author(s):  
Yanjie Yi ◽  
Youtian Shan ◽  
Shifei Liu ◽  
Yanhui Yang ◽  
Yang Liu ◽  
...  
Keyword(s):  
Biological Control ◽  
Root Rot ◽  
Bacillus Amyloliquefaciens ◽  
Biological Control Agent ◽  
Wheat Yield ◽  
Bipolaris Sorokiniana ◽  
Common Root ◽  
Bioactive Substances ◽  
Wheat Seedlings ◽  
Common Root Rot

Common root rot, caused by Bipolaris sorokiniana, is one of the most prevalent diseases of wheat and has led to major declines in wheat yield and quality worldwide. Here, strain XZ34-1 was isolated from soil and identified as Bacillus amyloliquefaciens based on the morphological, physiological, biochemical characteristics and 16S rDNA sequence. Culture filtrate (CF) of strain XZ34-1 showed a high inhibition rate against B.sorokiniana and had a broad antifungal spectrum. It also remarkably inhibited the mycelial growth and spore germination of B. sorokiniana. In pot control experiments, the incidence and disease index of common root rot in wheat seedlings were decreased after treatment with CF, and the biological control efficacy was significant, up to 78.24%. Further studies showed XZ34-1 could produce antifungal bioactive substances and had the potential of promoting plant growth. Lipopeptide genes detection with PCR indicated that strain XZ34-1 may produce lipopeptides. Furthermore, activities of defense-related enzymes were enhanced in wheat seedlings after inoculation with B.sorokiniana and treatment with CF, which showed induced resistance could be produced in wheat to resist pathogens. These results reveal that strain XZ34-1 is a promising candidate for application as a biological control agent against B.sorokiniana.

scholarly journals Genetic Determinants of Wheat Resistance to Common Root Rot (Spot Blotch), Fusarium Crown Rot, and Sharp Eyespot

2020 ◽  
Author(s):  
Jun Su ◽  
Jiaojie Zhao ◽  
Shuqing Zhao ◽  
Mengyu Li ◽  
Xiaofeng Shang ◽  
...  
Keyword(s):  
Root Rot ◽  
Spot Blotch ◽  
Crown Rot ◽  
Genetic Determinants ◽  
Common Root ◽  
Fusarium Crown Rot ◽  
Common Root Rot ◽  
Sharp Eyespot ◽  
Root And Crown Rot ◽  
Moderate Resistance

Due to the field soil changes, high density planting, and straw-returning methods, wheat common root rot (spot blotch), Fusarium crown rot (FCR), and sharp eyespot have become severe threatens to global wheat productions. Only a few wheat genotypes show moderate resistance to these root and crown rot fungal diseases, and the genetic determinants of wheat resistance to these devastating diseases have been poorly understood. This review summarizes the recent progress of genetic studies on wheat resistance to common root rot, Fusarium crown rot, and sharp eyespot. Wheat germplasms with relative higher resistance are highlighted and genetic loci controlling the resistance to each of the disease are summarized.

scholarly journals Temperature, Moisture, and Seed Treatment Effects on Rhizoctonia solani Root Rot of Soybean

Plant Disease ◽  
2003 ◽  
Vol 87 (5) ◽  
pp. 533-538 ◽  
Author(s):  
A. E. Dorrance ◽  
M. D. Kleinhenz ◽  
S. A. McClure ◽  
N. T. Tuttle
Keyword(s):  
Soil Moisture ◽  
Rhizoctonia Solani ◽  
Root Rot ◽  
Seed Treatment ◽  
Anastomosis Group ◽  
Control Measures ◽  
Root Weight ◽  
Wide Range ◽  
Plant Stand ◽  
Growth Chamber Studies

The effects of temperature and soil moisture on infection and disease development by Rhizoctonia solani on soybean were studied individually. In addition, the anastomosis group of R. solani isolates recovered from soybean from 35 fields in 15 counties was determined. All of the 44 isolates recovered in this study were AG-2-2 IIIB. Five isolates of R. solani were able to infect and colonize soybean roots and hypocotyls at 20, 24, 28, and 32°C in growth chamber studies. The temperatures evaluated in this study were not limiting to the isolates tested. In greenhouse studies, nine R. solani isolates and a noninoculated control were evaluated at 25, 50, 75, and 100% soil moisture holding capacity (MHC). Root weights were greater and percent stand averages higher at 50 and 75% than at 25 or 100% MHC; however, as percentage of control, the main effect on percent moisture for percent stand, plant height, or root weight was not significant. There were significant differences among the isolates for the percent stand, root rot rating, and root fresh weight of soybean in each study. In both temperature and moisture studies, the R. solani isolates could be separated as predominantly causing (i) seed rot, as detected by greatly reduced plant stand; (ii) root rot generally having no effect on plant stand but a high root rot rating and low root weight; or (iii) hypocotyl lesions, having no effect on plant stand, a low root rot score, and a high number of red lesions on the hypocotyl. In the greenhouse seed treatment evaluations of five fungicides, there was no fungicide by isolate interaction using these pathogenic types of R. solani. None of the seed treatments evaluated in this study provided 100% control of the four isolates tested. Due to the wide range of environmental factors that permit R. solani infection and disease on soybeans, other control measures that last all season, such as host resistance, should be emphasized.

COMPARATIVE STUDIES OF NORTH AMERICAN AND EUROPEAN CULTURES OF THE ROOT ROT FUNGUS, FOMES ANNOSUS (FR.) COOKE

1955 ◽  
Vol 33 (5) ◽  
pp. 416-428 ◽  
Author(s):  
D. E. Etheridge
Keyword(s):  
Growth Rate ◽  
North American ◽  
Growth Rates ◽  
Root Rot ◽  
Linear Growth ◽  
Morphological Characteristics ◽  
Dry Weight ◽  
Cellulolytic Activity ◽  
Ph Optimum ◽  
Two Cultures

Cultures of Fames annosus originating in Europe could not be distinguished from those originating in North America either by colony appearance, growth rate, pH optimum, or cellulolytic activity. Three growth rate types on 2.5% malt agar were recognized and these are ascribed to individual variation rather than to host or geographical influences. Successive subculturing produced variants that fell into three growth classes. Half of the isolates displayed spontaneous, but reversible, changes in growth rate and colony appearance during subculturing and this is discussed from the standpoint of genetical and environmental influences. Cultures displaying different morphological characteristics and linear-growth rates differed little metabolically; each had a similar pH optimum ranging from 4.6 to 5.5, and each proved capable of altering the initial acidity of the medium to a reaction which was more suitable for growth. Two cultures were characterized by double pH optima at 4.6 and 5.5. Cultures having different linear-growth rates produced about the same dry-weight of mycelium on a cellulose substrate in a semisynthetic nutrient solution. On the basis of a statistical analysis of cellulose utilization by representative isolates it was impossible to distinguish between North American and European cultures.

STUDIES ON FOOT AND ROOT ROT OF WHEAT: II. CULTURAL RELATIONSHIPS ON SOLID MEDIA OF CERTAIN MICRO-ORGANISMS IN ASSOCIATION WITH Ophiobolus graminis SACC.

1933 ◽  
Vol 8 (6) ◽  
pp. 545-552 ◽  
Author(s):  
W. C. Broadfoot
Keyword(s):  
Root Rot ◽  
Potato Dextrose Agar ◽  
Wheat Seedlings ◽  
Reliable Indication ◽  
Solid Media ◽  
Metabolic Products ◽  
Growth Reaction ◽  
Bacteria And Fungi ◽  
Micro Organisms ◽  
Pot Culture

The antagonistic and compatible growth relationships of 66 cultures of bacteria and fungi, most of which were from the soil, towards O. graminis on potato dextrose agar and Molisch's salt peptone agar, were compared with the effect of each on the virulence of this pathogene on wheat seedlings in open soil culture.Of the 21 cultures which controlled the virulence of O. graminis in the soil, only 15 of these were antagonistic on potato dextrose agar, while of the 45 cultures which gave intermediate or no control, 17 were compatible and 28 were decidedly antagonistic. From data secured indirectly, the antagonism or compatibility of the micro-organisms toward O. graminis, observed on potato dextrose agar, did not seem to depend on active alkali or acid more than on other metabolic products. The study apparently demonstrates that the growth reaction of various micro-organisms and O. graminis, associated on the two solid media used, is not a reliable indication that the same micro-organism will or will not suppress the virulence of this pathogene on wheat in soil in open pot culture.

Severity, Distribution, and Losses from Taproot Cankers Caused by Rhizoctonia solani in Peanuts1

1988 ◽  
Vol 15 (2) ◽  
pp. 73-75 ◽  
Author(s):  
John T. Turner ◽  
Paul A. Backman
Keyword(s):  
Rhizoctonia Solani ◽  
Surface Area ◽  
Disease Severity ◽  
Negative Correlation ◽  
Root Rot ◽  
High Frequency ◽  
Significant Negative Correlation ◽  
Anastomosis Group ◽  
Group 4

Abstract Research on the ecology of peanut roots from fields in Georgia, Florida, and Alabama revealed a high frequency of sunken, dark cankers on the taproot which persisted to harvest. Isolations from these cankers resulted in recovery of Rhizoctonia solani anastomosis group 4 (AG-4) from more than 50% of the cankers. A survey of peanut fields being harvested during early September revealed that 28% of the fields had an average of more than 50% of the taproot surface area cankered. In contrast, for fields in the same area harvested one month later, 77% had disease severities of less than 25% and none were greater than 50%. In an experiment conducted in 1984, roots from 64 plots were examined and rated for root rot severity and yield. When taproot disease severity was regressed against yield, a highly significant negative correlation (r2 − 0.60, P&lt;0.01) was found.

Diversité morphologique en culture, sensibilité au carbendazime et pouvoir pathogène du Tapesia yallundae (anamorphe : Pseudocercosporella herpotrichoides)

1995 ◽  
Vol 73 (9) ◽  
pp. 1379-1384 ◽  
Author(s):  
Peter Frei ◽  
Daniel Gindrat
Keyword(s):  
Growth Rate ◽  
Triticum Aestivum ◽  
Hordeum Vulgare ◽  
Rapid Growth ◽  
Slow Growth ◽  
Colony Growth ◽  
Sexual Stage ◽  
Pseudocercosporella Herpotrichoides ◽  
Tapesia Yallundae ◽  
Irregular Margin

Three types of colonies (WH, WA, and RA) have been characterized among 2245 isolates of Pseudocercosporella herpotrichoides on the basis of colony growth rate and appearance (W, rapid growth and regular margin; R, slow growth and irregular margin) and of the shape of the majority of conidia (H, coiled; A, straight). Apothecia of Tapesia yallundae (anamorph : P. herpotrichoides) were produced on naturally infected stems of winter wheat and barley. Apothecia of an undetermined discomycete were occasionally observed. The progeny of more than 1700 ascospores from 72 apothecia of T. yallundae was distributed among the three types of colonies. These types remained stable through successive conidial and mycelial subcultures. All three colony types were sometimes obtained from a single apothecium. WH and WA were the most common, while RH was never observed. WA isolates were more often resistant than WH isolates to carbendazim. Inoculations of wheat and barley stems with ascospores of T. yallundae were unsuccessful, while inoculations with conidia or mycelium resulted in eyespot lesions. During equivalent periods, RA isolates were less virulent than WH and WA. Key words: cereals, eyespot, Deuteromycetes, sexual stage, Hordeum vulgare, Triticum aestivum.

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