Relationship of Pectolytic Enzyme Production by Isolates of Sclerotium cepivorum Berk to their Pathogenicity

Elrazik, A. A. Abd; Shatla, M.N.; Rushdi, M. H.

doi:10.1016/s0044-4057(74)80041-9

Cited by 6 publications

(8 citation statements)

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“…3, 7, 12 and 2). Variation existed among virulence of the pathogen isolates reported herein confirm the previous findings of Tims (1948) and Abd-El-Razik et al (1974).…”

Section: Resultssupporting

confidence: 91%

“…Disease severity percentage of each isolate was recorded after two months from transplanting date by using 0 -4 disease scale described by Abd-El-Razik et al (1974). Data were statistically analyzed and means were compared using the LSD test (Gomez & Gomez 1984).…”

Section: Pathogenicity Testsmentioning

confidence: 99%

“…It has been reported that Sclerotium cepivorum Berk., the incitant of onion white rot, is a variable pathogen and consists of a heterogeneous group of strains (Abd-El-Razik et al 1974;Georgy & Coly-Smith 1982;Saeed & Abou-Elseoud 1990;Couch & Kohn 2000;Patricia et al 2002;Amin 2003). Differentiation between such strains could be by means of electrophoretic and PCR analysis of esterase (Chen & Swart 2001;Cao & Ye 2001), presence of major proteins (Novak & Kohn 1988;Saeed & Abou-Elseoud 1990) and DNA fingerprints (Couch & Kohn 2000;Patricia et al 2002;Tyson et al 2002;Amin 2003).…”

Section: Introductionmentioning

confidence: 99%

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Molecular characterization of European and Egyptian isolates ofSclerotium cepivorum, the incitant of onion white rot

Sallam

Elrazik

Hassan

et al. 2009

Archives Of Phytopathology And Plant Protection

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The tested European and Egyptian isolates of Sclerotium cepivorum were able to infect Giza 6 onion cultivar causing white rot disease with a different degrees of disease severity (ranging from sever to weak). The pattern of esterase isozymes produced by the tested isolates of the pathogen showed two main bands (arrows) which were different in density. Such differences in density of bands were present in every run and therefore appear to be indicators for differences among the tested isolates. Analysis of the protein pattern of the tested isolates of the pathogen indicated that the tested isolates had major proteins of a molecular weight of 52, 36, 23 and 16 kDa. Variation between isolates was detected by presence of bands of low molecular weight. Isolate Nos.

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“…3, 7, 12 and 2). Variation existed among virulence of the pathogen isolates reported herein confirm the previous findings of Tims (1948) and Abd-El-Razik et al (1974).…”

Section: Resultssupporting

confidence: 91%

Section: Pathogenicity Testsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Molecular characterization of European and Egyptian isolates ofSclerotium cepivorum, the incitant of onion white rot

Sallam

Elrazik

Hassan

et al. 2009

Archives Of Phytopathology And Plant Protection

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“…Destruction of epidermal cell walls beneath the stem base cuticle occurs two to three cells ahead of infection hyphae ( Stewart et al ., 1989b ). Sclerotium cepivorum produces the phytotoxin oxalic acid ( Stone & Armentrout, 1985) and a range of extracellular enzymes that degrade the cell wall, including polygalacturonases (PG, EC 3.2.1.15, Mankarios & Friend, 1980; Favaron et al ., 1993 ), pectinesterases (PE, EC 3.2.1.11, Abd El‐Razik et al ., 1974 ), cellulases, arabanases and xylanases ( Mankarios & Friend, 1980). However, the relative contribution of each enzyme to cellular dissolution has not been determined.…”

Section: Introductionmentioning

confidence: 99%

Histology of Sclerotium cepivorum infection of onion roots and the spatial relationships of pectinases in the infection process

Metcalf¹,

Wilson

1999

Plant Pathology

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Sclerotium cepivorum (isolate Sc4) hyphae penetrated the epidermis and hypodermis of onion roots and grew into the cortex. Immediately following penetration only the cells through which S. cepivorum grew were lysed, but subsequently cells were killed and cell walls disintegrated ahead of the infection hyphae. Sclerotium cepivorum produced two polygalacturonases (PG) and two pectinesterases (PE) in culture. These isozymes were also found in infected onion root tissues and another PG and a PE were occasionally detected. Two isozymes of PG and three isozymes of PE diffused ahead of the infection hyphae. The spatial distribution of these enzymes was associated with cell death and cell wall degradation. The epidermis, hypodermis, endodermis and vascular tissues were more resistant to hydrolysis than the cortex, but only the endodermis and cells within it retained nuclei following hydrolysis of the surrounding cortical tissues. The cavity within the root cortex became ®lled with swollen, vacuolate S. cepivorum hyphae.

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“…It is well known that the fungal metabolite oxalic acid is produced by S. cepivorum in culture and in infected onion plants and plays a pivotal role in the progress of onion infection (Stone and Armentrout 1985). Additionally, S. cepivorum secretes a group of extracellular enzymes during invasion of onion tissues that degrade the cell wall, including polygalacturonase and pectin methylesterase (Abd El-Razik et al 1974), cellulases, arabanases and xylanases (Mankarios and Friend 1980). Conversely, many fungal metabolites have been used as a potential opportunity to control plant pathogens.…”

Section: Discussionmentioning

confidence: 99%

Efficiency assessment of the antifungal metabolites from Sclerotium cepivorum against onion white rot disease

et al. 2015

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The inhibitory effects of secondary metabolites of Sclerotium cepivorum against itself were studied both in vitro and in vivo. The highest inhibition of fungal growth and a 98.6 % reduction in the number of sclerotia was obtained with 50 % culture filtrate. No sclerotial germination was observed on media amended with culture filtrates at 10, 25 and 50 %. Methanol extract of mycelia and sclerotia, and ethyl acetate extract of culture filtrate both exhibited over 90 % inhibition of S. cepivorum growth at 1200 ppm. A chloroform extract of culture filtrate resulted in 71.1 % inhibition at 1200 ppm. All extracts completely suppressed the formation and germination of sclerotia at 400, 800 and 1200 ppm. In greenhouse experiments, no disease was observed with the ethyl acetate extract when onion seedlings were dipped in the extract for 4 or 8 h. The GC-MS analysis revealed 28 compounds in the methanol extract. The methanol extract contained mainly hexadecanoic acid methyl ester (31.16 %), whereas 5-hydroxymethylfurfural, HMF, (36.40 %) was the main constituent of the ethyl acetate extract. These results suggest that the secondary metabolites of S. cepivorum are potential and promising antifungal agents for the control of onion white rot. These results can be also applied to reduce the incidence and severity of other diseases in different crops.

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Relationship of Pectolytic Enzyme Production by Isolates of Sclerotium cepivorum Berk to their Pathogenicity

Cited by 6 publications

References 0 publications

Molecular characterization of European and Egyptian isolates ofSclerotium cepivorum, the incitant of onion white rot

Molecular characterization of European and Egyptian isolates ofSclerotium cepivorum, the incitant of onion white rot

Histology of Sclerotium cepivorum infection of onion roots and the spatial relationships of pectinases in the infection process

Efficiency assessment of the antifungal metabolites from Sclerotium cepivorum against onion white rot disease

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