Root growth altered by compaction of a sandy loam soil affects severity of rhizoctonia root rot of wheat seedlings

2004 ◽  
Vol 44 (6) ◽  
pp. 595 ◽  
Author(s):  
J. S. Gill ◽  
S. Hunt ◽  
K. Sivasithamparam ◽  
K. R. J. Smettem
Keyword(s):  
Root Growth ◽  
Rhizoctonia Solani ◽  
Soil Profile ◽  
Soil Compaction ◽  
Anastomosis Group ◽  
Soil Conditions ◽  
Wheat Seedlings ◽  
Bare Patch ◽  
Compacted Soil ◽  
The Impact

Rhizoctonia solani Anastomosis Group 8 damages seedling roots of wheat, causing the 'bare-patch' disease. This makes the first 4 weeks after germination the most critical period for disease development. As the field inoculum of the pathogen is mainly concentrated in the surface 10 cm of soil, the rate of root growth becomes critical for the vulnerable tissues of the root to escape the attack from the inoculum zone. To evaluate the effect of alteration of root growth by soil compaction on disease severity, a study was undertaken in 40-cm-deep pots made from PVC pipes (8.7 cm diameter). Four depths of soil compaction (whole soil profile compacted, whole soil loose, upper 10 cm loose and compacted below, upper 20 cm loose and compacted below) were tested using sieved soil. Effective root length of infected seedlings was higher in the pots where the whole soil profile was compacted than others. Reduction in dry root weights, where soil was compacted to heights of 0, 17.5, 27.5 or 37.5 cm following inoculation, were 68, 30, 74 and 56%, respectively. Reduction in shoot weights was 52, 22, 66 and 44%, respectively. Eight days after incubation, microbial activity was greater where the soil was highly compacted than where there was a low level of soil compaction. Saprophytic growth in soil of Rhizoctonia solani Anastomosis Group 8 was higher in loosely packed soil than in compacted soil. This shows that higher impact of disease under compacted soil conditions is due to reduced root growth and that disturbing the soil below seeds can reduce the impact of disease.

scholarly journals Effect of Heavy Machine Traffic on Soil CO2 Concentration and Efflux in a Pinus koraiensis Thinning Stand

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1497
Author(s):  
Ikhyun Kim ◽  
Sang-Kyun Han ◽  
Mauricio Acuna ◽  
Heesung Woo ◽  
Jae-Heun Oh ◽  
...  
Keyword(s):  
Soil Compaction ◽  
Field Measurements ◽  
Co2 Concentration ◽  
Soil Bulk Density ◽  
Timber Harvesting ◽  
Pinus Koraiensis ◽  
Soil Conditions ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
The Impact

Mechanized timber harvesting is cost efficient and highly productive. However, mechanized harvesting operations are often associated with several environmental problems, including soil compaction and disturbance. Soil compaction impedes air circulation between the soil and atmosphere, which in turn results in increased concentrations of CO2 within soil pores. In this study, we investigated the impact of forest machine traffic on soil conditions to determine soil CO2 efflux (Fc), and soil CO2 concentrations (Sc). Field measurements included soil bulk density (BD), soil temperature (ST), soil water content (SWC), Fc, and Sc over a 3-year period at a specific thinning operation site (Hwacheon-gun) in the Gangwon Province of Korea. To assess the soil impacts associated with machine traffic, we established four machine-treatment plots (MT) characterized by different geographical and traffic conditions. The results revealed that BD, Sc, and SWC increased significantly on the disturbed track areas (p < 0.05). Furthermore, reduced soil Fc values were measured on the soil-compacted (machine disturbed) tracks in comparison with undisturbed (control) areas. Variations in BD, SWC, and Sc were significantly different among the four MT plots. Additionally, in comparison with undisturbed areas, lower Fc and higher Sc values were obtained in compacted areas with high soil temperatures.

Effect of Microbial Seed Treatment on Root Growth of Wheat under Compacted Soil Condition

2019 ◽  
Vol 6 (02) ◽  
Author(s):  
SURAJIT MONDAL ◽  
DEBASHIS CHAKRABORTY ◽  
SANGEETA PAUL
Keyword(s):  
Root Growth ◽  
Root Length ◽  
Soil Compaction ◽  
Seed Treatment ◽  
Root Length Density ◽  
Average Diameter ◽  
Soil Condition ◽  
Microbial Culture ◽  
Compacted Soil ◽  
Microbial Cultures

Soil compaction can seriously restrict root growth both in surface and subsurface soil layers, preventing the root system to uptake water and nutrients from deeper layers in wheat due to intensive puddling in rice. To understand the effect of compaction (BD1 = bulk density 1.4 g cm-3 and BD2 = 1.8 g cm-3) on root growth of wheat, a pot experiment was conducted in ambient condition during wheat growing period (November-April) in 2017-18. This experiment was done with microbially treated wheat seeds (M1 to M6) to observe the effects of microbial cultures on root growth under compacted soil condition in comparison to control where no seed treatment was done. BD1 registered a marginally 28% higher root length density than BD2. Among seed treatment with microbial cultures (MC), MC5 resulted in highest root length density (23% higher than the control). Unlike root length density, root volume density was influenced significantly (p less than 0.05) by microbial seed inoculation, although soil compaction had marginal impact. Average diameter of root varied significantly among treatments due to both soil compaction and microbial seed treatment (p less than 0.01). Average diameter was significantly higher (20%, p less than 0.01) in BD2 than BD1. MC2 recorded higher (45-33%, p less than 0.01) root diameter than other treatments but was comparable with MC3. It can be concluded that Seed treatment with suitable microbial culture can promote the crop growth in general and root growth in particular under compacted soil condition.

Mycelial Interactions and the Potential Use of Tuft Formation in Characterizing Rhizoctonia solani Isolates Infecting Cereals

1993 ◽  
Vol 41 (2) ◽  
pp. 253 ◽  
Author(s):  
HA Yang ◽  
K Sivasithamparam ◽  
PA Obrien
Keyword(s):  
Rhizoctonia Solani ◽  
Anastomosis Group ◽  
Potato Dextrose Agar ◽  
Bare Patch ◽  
Field Isolates ◽  
Mycelial Interactions ◽  
Causal Pathogen ◽  
Patch Disease ◽  
Potential Use ◽  
Compatible Interactions

Field isolates of Rhizoctonia solani anastomosis group (AG) 8, the most important causal pathogen of cereal bare-patch disease, were paired with each other and with tester strains of other AGs on potato-dextrose agar amended with charcoal (PDCA) to investigate mycelial interactions. Pairings among AG 8 field isolates produced compatible interactions of either tuft or merging reactions. Tufts formed between all paired field isolates from different pectic zymogram groups (ZGs) within AG 8, but pairings between genetically identical isolates showed merging reactions. Pairings of AG 8 field isolates with the tester strains of the other AGs led to incompatible interactions varying from merging line to barrage reactions. As formation of a tuft indicates that the paired isolates are able to anastomose and to form viable heterokaryons, the testing of mycelial interaction types, highlighted by tuft formation, may be used as a rapid procedure to characterise field isolates of R. solani obtained from cereals.

scholarly journals Silicon Dioxide Nanoparticles Induce Innate Immune Responses and Activate Antioxidant Machinery in Wheat Against Rhizoctonia solani

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2758
Author(s):  
Abdelrazek S. Abdelrhim ◽  
Yasser S. A. Mazrou ◽  
Yasser Nehela ◽  
Osama O. Atallah ◽  
Ranya M. El-Ashmony ◽  
...  
Keyword(s):  
Silicon Dioxide ◽  
Rhizoctonia Solani ◽  
Root Rot ◽  
Disease Suppression ◽  
Damping Off ◽  
Silicon Dioxide Nanoparticles ◽  
Destructive Effect ◽  
Wheat Seedlings ◽  
Wide Range ◽  
The Impact

The phytopathogenic basidiomycetous fungus, Rhizoctonia solani, has a wide range of host plants including members of the family Poaceae, causing damping-off and root rot diseases. In this study, we biosynthesized spherical-shaped silicon dioxide nanoparticles (SiO2 NPs; sized between 9.92 and 19.8 nm) using saffron extract and introduced them as a potential alternative therapeutic solution to protect wheat seedlings against R. solani. SiO2 NPs showed strong dose-dependent fungistatic activity on R. solani, and significantly reduced mycelial radial growth (up to 100% growth reduction), mycelium fresh and dry weight, and pre-, post-emergence damping-off, and root rot severities. Moreover, the impact of SiO2 NPs on the growth of wheat seedlings and their potential mechanism (s) for disease suppression was deciphered. SiO2 NPs application also improved the germination, vegetative growth, and vigor indexes of infected wheat seedlings which indicates no phytotoxicity on treated wheat seedlings. Moreover, SiO2 NPs enhanced the content of the photosynthetic pigments (chlorophylls and carotenoids), induced the accumulation of defense-related compounds (particularly salicylic acid), and alleviated the oxidative stress via stimulation of both enzymatic (POD, SOD, APX, CAT, and PPO) and non-enzymatic (phenolics and flavonoids) antioxidant defense machinery. Collectively, our findings demonstrated the potential therapeutic role of SiO2 NPs against R. solani infection via the simultaneous activation of a multilayered defense system to suppress the pathogen, neutralize the destructive effect of ROS, lipid peroxidation, and methylglyoxal, and maintain their homeostasis within R. solani-infected plants.

scholarly journals First Report of Rhizoctonia solani AG2-1 on roots of wheat in Kazakhstan

Plant Disease ◽  
2021 ◽  
Author(s):  
Göksel Özer ◽  
İmren Mustafa ◽  
Tugba Bozoglu ◽  
Abdelfattah A. Dababat
Keyword(s):  
Rhizoctonia Solani ◽  
Its Region ◽  
Triticum Aestivum L ◽  
Anastomosis Group ◽  
Universal Primers ◽  
Sodium Hypochlorite Solution ◽  
First Report ◽  
Pure Cultures ◽  
The Impact ◽  
Wheat Kernels

In June 2019, approximately 20 tillers of wheat (Triticum aestivum L.) were sampled at the ripening stage (Feekes scale 11) from four different fields in Almaty, Kazakhstan. Brown lesions (3-5 mm in length) were present on the roots of sampled plants, with 20% incidence. To determine the causal agent, diseased roots were surface disinfected in sodium hypochlorite solution (1%) for 3 min, rinsed triple with sterile distilled water, air-dried in a laminar flow hood, and plated onto one-fifth strength potato dextrose agar (PDA) supplemented with 50 ppm chloramphenicol. After three days, the hyphal fragments that developed from the sections were transferred to fresh PDA and incubated at 23°C with 12-h photoperiod for 7 days to obtain pure cultures. Brown pigmented fungal colonies with a constriction at the base of hyphal branches, septa near the branching point, and right-angled branching resembling Rhizoctonia solani were observed. The identification anastomosis group (AG) of a representative isolate for each field was conducted by sequencing the internal transcribed spacer (ITS) region of rDNA with the universal primers ITS4 and ITS5 (White et al. 1990). The resulting sequences of 693 bp length were deposited in GenBank (accession nos. MW898143:MW898146). These sequences were 100% identical to the isolate 8Rs of R. solani AG2-1 (accession no. AF354063). To confirm the pathogenicity of the four isolates, the colonized wheat kernels method described by Demirci (1998) was used to inoculate a sterile potting mix containing peat, vermiculite, and soil (1:1:1 by v/v/v) into which wheat (cv. Seri) was planted. Control pots were inoculated with sterile wheat kernels using the same procedure. Wheat plants were left to grow for four weeks under controlled environmental conditions with a 23°C temperature regime. During the period that the plants remained in the glasshouse, the typical light regime was 16 h. Brown lesions were observed on the roots of plants in the inoculated pots whereas no symptoms were observed on plants grown in the control pots. R. solani was consistently reisolated from symptomatic plants, thereby confirming Koch’s postulates. To our knowledge, this is the first report of R. solani AG2-1 on roots of wheat in Kazakhstan. R. solani AG2-1 isolates have been previously reported to be a weak pathogen to wheat (Roberts and Sivasithamparam 1986; Sturrock et al. 2015; Jaaffar et al. 2016; Özer et al. 2019). We suggest further studies are required to characterize the impact of R. solani AG2-1 in wheat. Considering crop rotation, the selection of non-host crops to this AG group is important to pathogen management, by reducing the amount of inoculum in the soil.

scholarly journals Plant roots sense soil compaction through restricted ethylene diffusion

Science ◽  
2021 ◽  
Vol 371 (6526) ◽  
pp. 276-280 ◽  
Author(s):  
Bipin K. Pandey ◽  
Guoqiang Huang ◽  
Rahul Bhosale ◽  
Sjon Hartman ◽  
Craig J. Sturrock ◽  
...  
Keyword(s):  
Root Growth ◽  
Soil Compaction ◽  
Warning Signal ◽  
Gas Diffusion ◽  
Wild Type ◽  
Compacted Soils ◽  
Compacted Soil ◽  
Modern Agriculture ◽  
Hormone Responses ◽  
Root Tissues

Soil compaction represents a major challenge for modern agriculture. Compaction is intuitively thought to reduce root growth by limiting the ability of roots to penetrate harder soils. We report that root growth in compacted soil is instead actively suppressed by the volatile hormone ethylene. We found that mutant Arabidopsis and rice roots that were insensitive to ethylene penetrated compacted soil more effectively than did wild-type roots. Our results indicate that soil compaction lowers gas diffusion through a reduction in air-filled pores, thereby causing ethylene to accumulate in root tissues and trigger hormone responses that restrict growth. We propose that ethylene acts as an early warning signal for roots to avoid compacted soils, which would be relevant to research into the breeding of crops resilient to soil compaction.

Evidence that each Rhizoctonia bare patch is dominated by an individual zymogram group (ZG) of Rhizoctonia solani AG-8

1993 ◽  
Vol 44 (6) ◽  
pp. 1175 ◽  
Author(s):  
GC MacNish ◽  
MW Sweetingham
Keyword(s):  
Rhizoctonia Solani ◽  
Western Australia ◽  
Soil Cores ◽  
Undisturbed Soil ◽  
Wheat Seedlings ◽  
Bare Patch ◽  
Infection Focus ◽  
Undisturbed Soil Cores

Studies of rhizoctonia bare patches in the southern part of the cereal belt of Western Australia indicate that each patch is dominated by an individual pectic zymogram group (ZG) of R. solani AG-8. R. solani was isolated from plants sampled from patches or from wheat seedlings grown in undisturbed soil cores removed from patches. The Rhizoctonia spp. isolated were characterized using electrophoresis in pectin-acrylamide gels. Four patch-forming zymogram groups (ZG1-1, ZG1-2. ZG1-4 and ZG1-5) were isolated. Of 121 patches examined, only five yielded more than one ZG. Two of these were due to the coalescing of two patches dominated by different zymogram groups. For the remaining three, there was only an occasional isolation of a ZG different from the dominant ZG. This may indicate a new infection focus endeavouring to establish in soil that another ZG occupies. Occasionally, patch-forming ZG1-1, ZG1-2, ZG1-4 and ZG1-5 were isolated from non-patch sites.

Temperature and water potential effects on growth and pathogenicity of Rhizoctonia solani AG-11 to lupin

1999 ◽  
Vol 45 (5) ◽  
pp. 389-395 ◽  
Author(s):  
S Kumar ◽  
K Sivasithamparam ◽  
J S Gill ◽  
M W Sweetingham
Keyword(s):  
Rhizoctonia Solani ◽  
Western Australia ◽  
Small Area ◽  
Linear Growth ◽  
Anastomosis Group ◽  
Potato Dextrose Agar ◽  
Wide Spread ◽  
Damping Off ◽  
Bare Patch ◽  
Ph Range

Rhizoctonia solani anastomosis group (AG) 11 causes serious damping-off and hypocotyl rot of lupins (Lupinus angustifolius L.) and is wide-spread in the northern grain-belt of Western Australia. We compared growth of AG-11 to AG-8, which causes bare-patch of grain crops including lupin. AG-11 grew significantly faster than AG-8 on potato dextrose agar (PDA) at several temperatures (10, 15, 20, 25, or 30°C) and also grew best within the pH range of 4-7. Growth of AG-8 was best at pH 7. There was no difference in the linear growth in soil of both AGs at 10°C, but AG-11 grew at a significantly faster rate at 20°C. Reduction in growth of AG-11 on osmotically adjusted PDA at temperatures between 10 and 30°C was more pronounced than that of AG-8. AG-11 caused very little lupin pre-emergence damping-off and hypocotyl rot at 10°C, and most severe hypocotyl rot was recorded at 20 and 25°C. Severity of hypocotyl rot caused by AG-11 at soil water potentials of -0.1, -0.07, and -0.05 MPa was higher than at -0.03 MPa. It appears that AG-11 is well suited to the environmental conditions of the relatively small area in Western Australia from which it is readily isolated.Key words: Rhizoctonia solani, anastomosis groups, osmotic potential, lupin.

The use of zymogram and anastomosis techniques to follow the expansion and demise of two coalescing bare patches caused by Rhizoctonia solani AG-8

1993 ◽  
Vol 44 (6) ◽  
pp. 1161 ◽  
Author(s):  
GC MacNish ◽  
CK McLernon ◽  
DA Wood
Keyword(s):  
Rhizoctonia Solani ◽  
Growing Season ◽  
Soil Cores ◽  
Undisturbed Soil ◽  
Wheat Seedlings ◽  
Bare Patch ◽  
Apparent Death ◽  
Low Levels ◽  
Undisturbed Soil Cores

Pectic zymogram characterization and anastomosis techniques were used to study the distribution of strains of R. solani AG-8 in a large rhizoctonia bare patch. Undisturbed soil cores were removed on nine occasions during the period 1988 to 1992. Identification of the isolates of R. solani from wheat seedlings grown in the cores demonstrated that the patch was a coalescence of two patches, each colonized by isolates of R. solani AG-8 representing different zymogram groups (ZG1-1 and ZG1-5). The demarcation between the two patches remained unchanged while both patches were active. Between the 1989 and 1990 seasons, the pathogen in half of the ZG1-5 patch died, or was reduced to such low levels that it was difficult to detect. In the remainder of the ZG1-5 patch, the pathogen died or was reduced to undetectable levels between the 1990-91 seasons. The ZG1-1 patch was evident at the beginning of the 1991 growing season and the pathogen could be isolated; however, by the end of the season the pathogen could not be isolated. In all these instances the demise of the patch was associated with the disappearance of field symptoms and an inability to isolate the pathogen and therefore the apparent death of the fungus in the soil.

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