Brachypodium distachyon genotypes vary in resistance to Rhizoctonia solani AG8

2016 ◽  
Vol 43 (2) ◽  
pp. 189 ◽  
Author(s):  
Katharina Schneebeli ◽  
Ulrike Mathesius ◽  
Alexander B. Zwart ◽  
Jennifer N. Bragg ◽  
John P. Vogel ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Root Rot ◽  
Quantitative Resistance ◽  
Brachypodium Distachyon ◽  
Genetic Resistance ◽  
Sole Source ◽  
Wheat Root ◽  
Anastomosis Group ◽  
Seedling Vigour ◽  
Rhizoctonia Root Rot

Brachypodium distachyon (L.)P.Beauv. (Bd) has previously been developed as a pathosystem model for the wheat root rot pathogen Rhizoctonia solani Kühn anastomosis group 8 (AG8). Here we explore variation in resistance to R. solani AG8 in Bd, to determine whether genomic tools could be used to find Bd genes involved in the grass defence response, with the aim of using this information for the improvement of Rhizoctonia root rot resistance in wheat. We looked for variation in resistance to R. solani AG8 in a diverse Bd natural accession collection and in Bd T-DNA insertion lines selected based on putative mechanisms reported for tagged genes. All lines were susceptible to the pathogen. Repeatable and significant variation in resistance was measured in both groups, with greater variation in resistance found across the natural accessions than in the T-DNA lines. The widest and most repeatable variation in resistance was between lines Koz-3 and BdTR 13a. The ratio of R. solani AG8-inoculated to uninoculated root length for line Koz-3 was 33% greater than the same ratio for line BdTR 13a. The increased resistance of Koz-3 was associated with nodal root initiation in response to the pathogen. A negative correlation between seedling vigour and resistance was observed, but found not to be the sole source of variation in resistance to R. solani AG8. The only T-DNA line with significantly greater resistance to R. solani AG8 than the reference line had an insertion in a putative galactosyltransferase gene; however, this result needs further confirmation. Genetic resistance to Rhizoctonia root rot is not available in wheat cultivars and only a few instances of quantitative resistance to the pathogen have been described within close relatives of wheat. Brachypodium distachyon offers potential for further investigation to find genes associated with quantitative resistance and mechanisms of tolerance to R. solani AG8.

scholarly journals Characterizing and Mapping Resistance in Synthetic-Derived Wheat to Rhizoctonia Root Rot in a Green Bridge Environment

2016 ◽  
Vol 106 (10) ◽  
pp. 1170-1176 ◽  
Author(s):  
A. K. Mahoney ◽  
E. M. Babiker ◽  
T. C. Paulitz ◽  
D. See ◽  
P. A. Okubara ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Root Rot ◽  
Recombinant Inbred Lines ◽  
Genetic Resistance ◽  
Genotyping By Sequencing ◽  
Interval Mapping ◽  
Environmentally Sustainable ◽  
Soilborne Disease ◽  
Rhizoctonia Root Rot ◽  
Green Bridge

Root rot caused by Rhizoctonia spp. is an economically important soilborne disease of spring-planted wheat in growing regions of the Pacific Northwest (PNW). The main method of controlling the disease currently is through tillage, which deters farmers from adopting the benefits of minimal tillage. Genetic resistance to this disease would provide an economic and environmentally sustainable resource for farmers. In this study, a collection of synthetic-derived genotypes was screened in high-inoculum and low-inoculum field environments. Six genotypes were found to have varying levels of resistance and tolerance to Rhizoctonia root rot. One of the lines, SPBC-3104 (‘Vorobey’), exhibited good tolerance in the field and was crossed to susceptible PNW-adapted ‘Louise’ to examine the inheritance of the trait. A population of 190 BC1-derived recombinant inbred lines was assessed in two field green bridge environments and in soils artificially infested with Rhizoctonia solani AG8. Genotyping by sequencing and composite interval mapping identified three quantitative trait loci (QTL) controlling tolerance. Beneficial alleles of all three QTL were contributed by the synthetic-derived genotype SPCB-3104.

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.

Role of antibiosis in antagonism of Streptomyces hygroscopicus var. geldanus to Rhizoctonia solani in soil

1984 ◽  
Vol 30 (12) ◽  
pp. 1440-1447 ◽  
Author(s):  
Craig S. Rothrock ◽  
David Gottlieb
Keyword(s):  
Disease Control ◽  
Rhizoctonia Solani ◽  
Root Rot ◽  
Antibiotic Production ◽  
Streptomyces Hygroscopicus ◽  
Soil Extracts ◽  
Rhizoctonia Root Rot ◽  
Inhibitory Compounds ◽  
Affected Plant

Streptomyces hygroscopicus var. geldanus controlled rhizoctonia root rot of pea in previously sterilized soil if incubated for 2 or more days prior to infesting soil with Rhizoctonia solani and planting. Streptomyces hygroscopicus also reduced saprophytic growth and the population of R. solani in soil. Growth of R. solani was inhibited by geldanamycin, an antibiotic produced by S. hygroscopicus, on nutrient media. Methanol extracts of soils in which the antagonist was incubated for 2 or more days inhibited growth of R. solani. Geldanamycin concentration was 88 μg per gram of soil after 7 days of incubation. Bioautography of soil extracts indicated that the inhibitory compounds were geldanamycin and two other compounds, also found in the geldanamycin standard. The period of incubation necessary for antibiotic production and disease control was similar, with no disease control occurring where no antibiotic was detected. Amending soil with geldanamycin, in amounts equivalent to that produced after 2 or 7 days of incubation, controlled disease and reduced saprophytic growth of the pathogen. Lesser amounts of the antibiotic did neither. No evidence for antagonism owing to competition (nitrogen, carbon) or parasitism was found. Streptomyces hygroscopicus and geldanamycin also affected plant growth.

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<0.01) was found.

scholarly journals First report of collar and root rot of faba bean caused by Rhizoctonia solani AG-2-2 IIIB in Bangladesh

Plant Disease ◽  
2021 ◽  
Author(s):  
S. K. Paul ◽  
Dipali Rani Gupta ◽  
Nur Uddin Mahmud ◽  
A.N.M. Muzahid ◽  
Tofazzal Islam
Keyword(s):  
Rhizoctonia Solani ◽  
Faba Bean ◽  
Root Rot ◽  
Disease Incidence ◽  
Management Strategies ◽  
Its Region ◽  
Anastomosis Group ◽  
Grain Legume ◽  
Collar And Root Rot ◽  
Wheat Kernels

Faba bean (Vicia faba L.) is an underutilized promising grain legume commercially grown in central and northern part of Bangladesh (Yasmin et al. 2020). In January 2021, faba bean plants exhibiting symptoms of collar and root rot and yellowing of leaves were observed in thirty plots of an experimental field at the Bangladesh Agricultural University (24.75° N, 90.50° E), Mymensingh, Bangladesh. Infected plants had dark brown to black lesions on the roots, extending above the collar region. An average disease incidence and severity was 7.16% and 6.91%, respectively. Eight diseased plants were collected from the field by uprooting one plant from each of eight randomly selected experimental plots and surface disinfected with sodium hypochlorite (0.2%) for 3 min followed by 1 min in ethanol (70%), and then rinsed three times with distilled water and dried on sterile paper towels. Collar and root pieces (5×5 mm) of symptomatic tissues were placed on Potato Dextrose Agar (PDA). Plates were incubated at 25°C for three days and isolates were purified from single-tip culture. The isolates produced brown colored mycelia often with brown sclerotia. Under microscope, fungal colonies exhibited right–angled branching with constriction at the base of hyphal branches and a septum near the originating point of hyphal branch consistent with the description of Rhizoctonia solani Kuhn (Sneh et al. 1991). The isolates grew at 35°C on PDA (5 mm/24). Molecular identification of the isolates BTRFB1 and BTRFB7 was determined by sequencing the rDNA internal transcribed spacer (ITS) region using primers ITS1 and ITS4 (White et al. 1990). A BLAST search showed that the sequences (GenBank Accession nos. MZ158299.1 and MZ158298.1) had 99.28% similarity with R. solani isolates Y1063 and SX-RSD1 (GenBank Accession nos. JX913811.1 and KC413984.1, respectively). Phylogenetic analysis revealed that the present isolates grouped with R. solani anastomosis group AG-2-2 IIIB. To confirm pathogenicity, both isolates were grown individually on sterile wheat kernels at 28°C for 6 days (D’aes et al. 2011). Faba bean seedlings were grown in plastic pots containing sterile potting mix (field soil/composted manure/sand 2:2:1 [v/v]). Two-week-old plants were inoculated by placing five infested wheat seeds adjacent to the roots. Control pots were inoculated with sterile wheat kernels using the same procedure. Plants were placed in a growth room with a 16 h/8 h light/dark photoperiod at 25 ± 2°C after inoculation. Fifteen days after inoculation, typical collar and root rot symptoms were developed on inoculated plants, similar to symptoms observed in the field. Control plants remained non-symptomatic. Finally, six isolates of R. solani were isolated from the symptomatic plants and identified by morphological and molecular analysis. Rhizoctonia solani is the causal agent of seed and root rot, hypocotyl canker, and seedling damping-off diseases of faba bean in many other countries (Rashid and Bernier 1993; Assunção et al. 2011). To our knowledge, this is the first confirmed report of Rhizoctonia solani causing collar and root rot of faba bean in Bangladesh. This finding will be helpful for the development of management strategies to control this disease and to expand the production of faba bean in Bangladesh.

Effect of nitrogen and residual copper on the occurrence of Rhizoctonia bare patch in wheat grown near Esperance, Western Australia

1991 ◽  
Vol 31 (2) ◽  
pp. 259 ◽  
Author(s):  
RF Brennan
Keyword(s):  
Grain Yield ◽  
Rhizoctonia Solani ◽  
Ammonium Nitrate ◽  
Western Australia ◽  
Root Rot ◽  
Plant Nutrition ◽  
Bare Patch ◽  
Grain Yields ◽  
Cu Deficiency ◽  
Rhizoctonia Root Rot

The area of rhizoctonia bare patch and the incidence and severity of rhizoctonia root rot (caused by Rhizoctonia solani Khnn) were reduced by the application of ammonium nitrate fertiliser. Residual copper (Cu) from a Cu fertiliser treatment in 1967 had no effect on the area of rhizoctonia bare patch or the incidence and severity of root rot. With no applied nitrogen (N), 17.6% (mean of residual Cu levels) of the plot was affected by patches while the area of plot affected by patches declined to 4.2% where 92 kg N/ha had been applied. The incidence and severity of rhizoctonia root rot declined from 45.9 and 27.0% to 32.7 and 9.1%, respectively, with the application of N fertiliser. The grain yield of wheat supplied with adequate Cu increased although the level of N fertiliser exceeded that considered adequate for plant nutrition. The response is explained by the control of rhizoctonia bare patch. The area of rhizoctonia patches and the incidence and severity of rhizoctonia root rot decreased with the application of N, and with adequate Cu fertiliser (2.2 kg Cu/ha), the grain yields increased. However, with marginal and deficient levels of applied Cu fertiliser, the application of N fertiliser induced Cu deficiency in wheat plants, and the grain yields declined although rhizoctonia patches were reduced.

Organic matter input influences incidence of root rot caused by Rhizoctonia solani AG8 and microorganisms associated with plant root disease suppression in three Australian agricultural soils

Soil Research ◽  
2019 ◽  
Vol 57 (4) ◽  
pp. 321 ◽  
Author(s):  
Rowena S. Davey ◽  
Ann M. McNeill ◽  
Stephen J. Barnett ◽  
Vadakattu V. S. R. Gupta
Keyword(s):  
Rhizoctonia Solani ◽  
Root Rot ◽  
Microbial Biomass Carbon ◽  
Plant Root ◽  
Abiotic Factors ◽  
Root Disease ◽  
Disease Suppression ◽  
Gaeumannomyces Graminis ◽  
Wheat Seedlings ◽  
Rhizoctonia Root Rot

Soil-borne plant root disease caused by Rhizoctonia solani AG8 is prevalent in cereal farming systems worldwide, particularly in semiarid agricultural regions. A controlled environment study was undertaken using three Australian soils to test the hypothesis that OM input from crop roots and residues decreases infection by Rhizoctonia root rot via biologically mediated disease suppression. The specific aim was to determine the relative effect of two different OM inputs (wheat stubble or roots) on (a) abundance (DNA) of the pathogen R. solani AG8 and soil organisms putatively associated with disease suppression, and (b) incidence of Rhizoctonia root rot infection of wheat seedlings (% root infected). An increase in microbial biomass carbon (C) following OM amendment indicated a potential for enhanced general biological disease suppression in all soils. OM inputs also increased the population size (DNA) of certain bacteria and fungi putatively associated with specific suppression for Rhizoctonia root rot, suggesting a C resource-mediated change in microbial functions related to disease suppression. There were no significant changes to measured pathogens with stubble addition. However, OM inputs via root residues and rhizodeposits from living roots increased the populations of R. solani AG8 and Gaeumannomyces graminis var. tritici so that in subsequently planted wheat there was greater incidence of root disease infection and reduced plant shoot and root DM compared with that following OM input as stubble. Differences between soils in terms of plant and soil organism responses to each OM input suggest that abiotic factors modify the development of biological disease suppression and the expression of the disease.

scholarly journals Influence of selected Rhizoctonia solani isolates on sugar beet seedlings

2016 ◽  
Vol 56 (2) ◽  
pp. 116-121
Author(s):  
Paweł Skonieczek ◽  
Mirosław Nowakowski ◽  
Jacek Piszczek ◽  
Marcin Żurek ◽  
Łukasz Matyka
Keyword(s):  
Sugar Beet ◽  
Rhizoctonia Solani ◽  
Root Rot ◽  
Laboratory Tests ◽  
Anastomosis Group ◽  
Damping Off ◽  
Highly Pathogenic ◽  
Breeding Lines ◽  
Brown Root Rot

Abstract From 2008 to 2010 the levels of sugar beet seedlings infection caused by Rhizoctonia solani were compared in laboratory tests. Seven sugar beet lines were tested: H56, H66, S2, S3, S4, S5 and S6 as well as three control cultivars: Carlos, Esperanza and Janosik. Sugar beet lines with tolerance to rhizoctoniosis and cultivars without tolerance were infected artificially by R. solani isolates: R1, R28a and R28b. These isolates belong to the second anastomosis group (AG), which is usually highly pathogenic to beet roots. The aim of the experiment was to test whether the tolerance of sugar beet genotypes to R. solani AG 2 prevents both root rot, and damping-off of seedlings, induced by the pathogen. Sugar beet lines tolerant to brown root rot in laboratory tests were significantly less sensitive to infection of the seedlings by R. solani AG 2 isolates in comparison to control cultivars. Rhizoctonia solani AG 2 isolates demonstrated considerable differences in pathogenicity against seedlings of sugar beet lines and cultivars. The strongest infection of sugar beet seedlings occurred with the isolate R28b. The greatest tolerance to infection by AG 2 isolates was found for the S5 and S3 breeding lines.

scholarly journals First Report of Petunia Root Rot Caused by Rhizoctonia solani in Argentina

Plant Disease ◽  
2004 ◽  
Vol 88 (1) ◽  
pp. 86-86
Author(s):  
E. R. Wright ◽  
M. C. Rivera ◽  
K. Asciutto ◽  
L. Gasoni ◽  
V. Barrera ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Root Rot ◽  
Disease Incidence ◽  
Common Garden ◽  
Anastomosis Group ◽  
Fluorescent Light ◽  
First Report ◽  
Blue Solution ◽  
Crown And Root Rot ◽  
Species Taxonomy

Common garden petunias (Petunia × hybrida Hort. Vilm.-Andr.) are herbaceous annual plants with brightly colored flowers up to 10 cm in diameter. During the winter of 2002, crown and root rot were observed on plants (cv. Ultra) growing in five greenhouses in Buenos Aires. Affected plants were randomly distributed in the greenhouses, and mean disease incidence in all the greenhouses was 26%. Basal leaves turned yellow and gradually became necrotic, and infected plants were often killed. Small pieces of affected tissues were disinfested in 2% sodium hypochlorite for 1 min and plated on 2% potato dextrose agar (PDA). Fifteen isolates identified to the genus Rhizoctonia were obtained. Fungal colonies were initially white, turned brown with age, and produced irregularly shaped, brown sclerotia. Hyphal branched at right angles, were constricted at the base of the branch near the union with main hyphae, and septate near the constriction. Basidia were not observed in the greenhouses or on the plates. Isolates were cultivated on water agar and incubated at 25°C for 3 days. Hyphal cells were determined to be multinucleate when stained with 1% aniline blue solution (2) and examined at ×400. Anastomosis group of one isolate was determined by using AG-4 HG II, AG-1 IA, AG-1 IB, AG-1 IC, AG-2 2-1, and AG-2 2IIIB tester strains of Rhizoctonia solani that includes isolates reported to be pathogenic on ornamentals (1). Anastomosis was observed only with strains of AG-4 HG II. Pathogenicity on this isolate was conducted on potted, healthy, adult plants that were 10 to 22 cm high and flowering. Thirty-five plants were inoculated by placing 1 cm2 pieces of PDA from 7-day-old mycelial cultures near the base of the stem. Twelve control plants were treated with 1 cm2 PDA plugs. Plants were kept at 22 to 24°C, >95% relative humidity, and 12 h of fluorescent light. Wilt symptoms due to basal stem rot appeared 7 days after inoculation, and all the inoculated plants died within 27 days. Control plants remained disease free. The pathogen was reisolated from symptomatic tissues, completing Koch's postulates. To our knowledge, this is the first report of R. solani causing disease on petunia in Argentina. References: (1) D. M. Benson and D. K. Cartwright. Ornamental diseases incited by Rhizoctonia spp. Pages 303–314 in: Rhizoctonia species: Taxonomy, Molecular Biology, Ecology, Pathology and Disease Control. B. Sneh et al., eds. Kluwer Academic Publishers, London, England, 1996. (2) C. C. Tu and J. W. Kimbrough. Mycologia 65:941, 1973.

scholarly journals Synergy of Anaerobic Soil Disinfestation and Trichoderma spp. in Rhizoctonia Root Rot Suppression

2021 ◽  
Vol 5 ◽  
Author(s):  
Ram B. Khadka ◽  
Sally A. Miller
Keyword(s):  
Carbon Source ◽  
Rhizoctonia Solani ◽  
Wheat Bran ◽  
Root Rot ◽  
Carbon Sources ◽  
Chicken Manure ◽  
Treated Soil ◽  
Soil Disinfestation ◽  
Anaerobic Soil Disinfestation ◽  
Rhizoctonia Root Rot

Potential synergy between anaerobic soil disinfestation (ASD) and Trichoderma spp. in suppression of Rhizoctonia root rot in radish was evaluated. A split-plot design with three replications was used; main plots were Trichoderma harzianum T22, Trichoderma asperellum NT25 and a non-Trichoderma control. Subplots were ASD carbon sources wheat bran, molasses, chicken manure, and mustard greens and two non-amended controls: anaerobic (covered and flooded) and aerobic (not covered or flooded). Carbon sources and Rhizoctonia solani inoculant were mixed with soil, placed in pots, and flooded, followed by drenching Trichoderma spore suspensions and sealing the pots in zip-lock bags. After 3 weeks, bags were removed, soil was aired for 1 week and radish “SSR-RR-27” was seeded. Rhizoctonia root rot severity and incidence were lowest in radish plants grown in ASD-treated soil amended with wheat bran, molasses, or mustard greens across all Trichoderma treatments. Disease severity was lower in radish plants treated with NT25 than with T22 or the non-Trichoderma control across all ASD treatments, and in radish grown in ASD-treated soil amended with wheat bran plus NT25 compared to ASD-wheat bran or NT25 alone. Rhizoctonia solani populations were significantly reduced by ASD treatment regardless of carbon source, while Trichoderma populations were not affected by ASD treatment with the exception of ASD-mustard greens. The interactions of either Trichoderma isolate and ASD with most carbon sources were additive, while T22 with ASD-molasses and NT25 with ASD–wheat bran interactions were synergistic in reducing disease severity. One interaction, T22 with ASD-chicken manure was antagonistic. Enhancement of ASD efficacy in suppressing soilborne diseases such as Rhizoctonia root rot by additional soil amendment with Trichoderma spp. during the process appears to be dependent on both Trichoderma isolate and ASD carbon source.

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