Production of Oxalic Acid by Sclerotium cepivorum during Infection of Onion

Stone, Harriet; Armentrout, V. N.

doi:10.2307/3793350

Cited by 23 publications

(7 citation statements)

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“…However, Micales and Highley (26) could not establish a correlation between the wood-decaying ability of various isolates of Poria placenta (Postia placenta) and their oxalic acid production. The importance of oxalic acid during the invasion of host tissue by phytopathogenic fungi has been reported previously (5,24,25,33). It has been suggested that the oxalic acid produced by Sclerotium rolfsii during pathogenesis acts synergistically with endopolygalacturonase, lowering the pH of the infected tissues to a level optimal for the activity of this enzyme.…”

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confidence: 68%

Production and Degradation of Oxalic Acid by Brown Rot Fungi

Espejo

Agosín

1991

Appl Environ Microbiol

114

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Our results show that all of the brown rot fungi tested produce oxalic acid in liquid as well as in semisolid cultures. Gloeophyllum trabeum, which accumulates the lowest amount of oxalic acid during decay of pine holocellulose, showed the highest polysaccharide-depolymerizing activity. Semisolid cultures inoculated with this fungus rapidly converted '4C-labeled oxalic acid to CO2 during cellulose depolymerization. The other brown rot fungi also oxidized '4C-labeled oxalic acid, although less rapidly. In contrast, semisolid cultures inoculated with the white rot fungus Coriolus versicolor did not significantly catabolize the acid and did not depolymerize the holocellulose during decay. Semisolid cultures of G. trabeum amended with desferrioxamine, a specific iron-chelating agent, were unable to lower the degree of polymerization of cellulose or to oxidize "4C-labeled oxalic acid to the extent or at the rate that control cultures did. These results suggest that both iron and oxalic acid are involved in cellulose depolymerization by brown rot fungi.

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confidence: 68%

Production and Degradation of Oxalic Acid by Brown Rot Fungi

Espejo

Agosín

1991

Appl Environ Microbiol

114

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“…Many nuclei were not stainable by the Feulgen method in this tissue, but there is no evidence that PE and PG are primary agents of cell death. Sclerotium cepivorum produces phytotoxic oxalic acid, which is known to act synergistically with PG by lowering the pH to the optimum for enzyme activity ( Stone & Armentrout, 1985), and in Sclerotium rolfsii infections oxalic acid has been shown to move systemically ahead of the hyphae ( Bateman & Beer, 1965). Metcalf (1993) noted that large numbers of tetragonal crystals of similar form to calcium oxalate were precipitated in the cortex and the xylem of onion roots in advance of hyphae.…”

Section: Discussionmentioning

confidence: 99%

“…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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“…Following penetration of the root epidermis, S. cepivorum invades cortical parenchyma both intra‐ and intercellularly causing extensive tissue degradation (Abd‐El‐Razik et al ., 1973). S. cepivorum produces the phytotoxin oxalic acid (Stone & Armentrout, 1985) and pectin‐degrading isoenzymes of polygalacturonase (PG) and pectinesterase (PE), which diffuse several millimetres ahead of infection hyphae, and are associated with extensive disintegration of the cortical tissues. Adjacent epidermal and stele tissues remain intact.…”

Section: Introductionmentioning

confidence: 99%

The process of antagonism of Sclerotium cepivorum in white rot affected onion roots by Trichoderma koningii

Metcalf

Wilson

2001

Plant Pathology

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Trichoderma koningii (strain Tr5) grew in the epidermal mucilage of onion roots without entering healthy epidermal tissue. When placed on the epidermis of Sclerotium cepivorum‐infected roots, T. koningii colonized epidermal passage cells, with little colonization of other epidermal tissues, then branched and spread throughout the root cortical tissues damaged by enzymes and toxins which diffused ahead of S. cepivorum hyphae, and impeded the path of the infection. When T. koningii colonized infected tissue, many S. cepivorum hyphae became detached at septa, cell walls dissolved and many hyphal apices burst. Contact between hyphae was not necessary for lysis to occur. T. koningii produced two endochitinases (Rf 0·15 and 0·24) and two exo‐acting chitinolytic enzymes (Rf 0·46 and 0·62) during degradation of crabshell chitin and S. cepivorum cell walls. The Rf 0·24 and 0·46 proteins were detected when T. koningii colonized S. cepivorum‐infected roots and are likely to be a component of the antagonism process.

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Production of Oxalic Acid by Sclerotium cepivorum during Infection of Onion

Cited by 23 publications

References 0 publications

Production and Degradation of Oxalic Acid by Brown Rot Fungi

Production and Degradation of Oxalic Acid by Brown Rot Fungi

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

The process of antagonism of Sclerotium cepivorum in white rot affected onion roots by Trichoderma koningii

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