Rhizoctonia solani

The PNL exhibits an optimum pH of 9.5 (figure 6) and an optimum temperature of 55" C (figure 7). Lyases catalyze the reaction in an alkaline or in a neutral medium at high temperatures [32] pectin lyase from Phoma medicaginis var. pinodella showed an optimum pH of 7.5 [25], endopectate lyase from Fusarium solani f sp. pisi showed an optimum pH of 9.4 [31], and pectate lyase fi om Rhizoctonia solani showed an optimum pH of 8.0 [34]. 

The enzyme had a requirement for calcium. The addition of EDTA to the reaction mixtures, resulted in complete loss of activity, whereas the addition of CaCl2 increased the activity (figure 8). Presumably, sufficient contaminating calcium ions were present in the dialyzed enzyme and substrate mixture to permit the limited activity of the controls, but apparently these were removed by chelation with EDTA. The optimum concentration was in the range of 5 to 15 M, and higher concentration resulted in a decrease in activity. Phoma medicaginis var. pinodella synthesizes a pectin lyase that lacked an absolute requirement for calcium ions but maximum enzyme activity required the presence of 1 mM Ca [25]. The lyase from Fusarium solani f sp. phaseoli, that is active on pectin and pectic acid, is calcium-dependent [30]. Most of the pectate lyases characterized are calcium-dependent the pectate lyase from Rhizoctonia solani [34] and the endopectate lyase fi om Fusarium solani f sp. pisi [31]. 

Many rhizobacteria are classified as chitinolytic and, for example, Serratki marsescens, which excretes chitinase, was found to be an effective biocontrol agent against Sclerotium rolfsii (135). Similarly, Aeromonas caviae was found to reduce disease caused by Rhizoctonia solani, Fusarium oxysporuin, and Sclerotium rolfsii (136). There is also evidence to support the role of P-l,3 glucanase in biocontrol of soil-borne plant pathogens (137). 

C. R. Howell and R. D. Stipanovic, Control of Rhizoctonia solani on cotton seedlings with Pseudomonas fluorescens and with an antibiotic produced by the bacterium, Phytopathology 69 480 (1979). 

Flutolanil is a benzanilide fungicide discovered and developed by Nihon Nohyaku Co., Ltd. Flutolanil exhibits excellent control against the following pathogens at rates of 300-1000gha (foliar spray), 1.5-3.0gkg (seed treatment) and 2.5-10.0 kg ha (soil incorporation) Rhizoctonia solani on rice. 

All the pectin lyases so far described are of fungal origin and are secreted extracellularly. Production of pectin lyase by Rhizoctonia solani, Botrytis cinerea, and Fusarium oxysporum f. lycopersici was induced by pectate with D-glucose,265 pectin showing a lower inductive effect.231... 

Pullman GS, DeVay JE, Garber RH, Weinhold AR (1981b) Soil solarization Effects on Verticillium wilt of cotton and soilbome populations of Verticillium dahliae, Pythium spp., Rhizoctonia solani, and Thielaviopsis basicola. Phytopathology 71 954-959 Rabinowitch HD, Katan J, Ben David B, Rotem L, Zig U (1985) Soil solarization in onion effects in successive years. Hassadeh 65 1792... 

Rodriguez Perez A, Diaz Hernandez S, Gallo Llobet L (2004) Eradication of Phytophthora nico-tianae and Rhizoctonia solani by double layer solarization in tomato seedbeds. Acta Hortic (ISHS) 698 207-211... 

Iron toxicity is a syndrome of disorders associated with large concentrations of Fe + in the soil solution. It is only found in flooded soils. A wide range of concentrations produce the symptoms, from 1000 to only 10mgL in soils with poor nutrient status—especially of P or K—or with respiration inhibitors such as H2S. There are large differences in tolerance between rice varieties. The effects include internal damage of tissues due to excessive uptake of Fe + impaired nutrient uptake, especially of P, K, Ca and Mg and increased diseases associated with imbalanced nutrition, such as brown leaf spot (caused by Helminthospo-rium oryzae), sheath blight (caused by Rhizoctonia solani) and blast (caused by Pyricularia oryzae). 

Wood SG, Gottheb D (1978) Evidence from mycelial studies for differences in the sterol biosynthetic pathway of Rhizoctonia solani and Phytophthora cinnamomi. Biochem J 170 343 Nes WD et al (1986) A comparison of cycloartenol and lanosterol biosynthesis and metabolism by the Oomycetes. Expeiientia 42 556... 

Gliotoxin, isolated by Winding in 1932 from Gliocladium fimbriaturn was found anatagonistic to Rhizoctonia solani, thus helpful against the root-rot of potato and tomato. 

Antimycin A is effective against Altemaria solani spores(42)5 karumin is effective against Rhizoctonia solani ( iD. Nikkomycin is being used to cure trees of Dutch elm disease in Hamden, Connecticut(44). It inhibits the formation of chitin and stops the myceTia of Ceratocy-stis ulmi from growing normally. 

Antifungal activity. Ethanol (50%) extract of the dried leaf was active on Rhizoctonia solani, mycelial inhibition was 65.99% . Water extract of the fresh leaf on agar plate... 

CS229 Renu. Fungitoxicity of leaf extracts of CS241 some higher plants against Rhizoctonia solani Kuehn. Nat Acad Sci Lett 1983 ... 

Guenoune, D. et al.. The defense response elicited by the pathogen Rhizoctonia solani is suppressed by colonization of the AM-fungus Glomus intraradices, Plant ScL, 160, 925, 2001. 

Two known dihydroflavonols, 3-hydroxy-5-methoxy-6,7-methylenedioxyflavanone and 3,5,7,4 -tetrahydroxy-3 -methoxyflavanone, are produced as phytoalexins by sugarbeet roots Beta vulgaris, Chenopodiaceae) when inoculated with Rhizoctonia solani. They had not been previously reported for B. vulgaris ... 

Elliger, C.A. and Halloin, J.M., Phenolics induced in Beta vulgaris by Rhizoctonia solani infection. Phytochemistry, 37, 691, 1994. 

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