A rôle for β-glucanases in the parasitism of cereals by Claviceps purpurea

Dickerson, A. G.; Mantle, Peter G.; Nisbet, Louis J.; Shaw, Barbara I.

doi:10.1016/0048-4059(78)90018-8

Cited by 15 publications

(3 citation statements)

References 26 publications

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“…These findings are consistent with the well-established principle that all these oligosaccharides containing one molecule of glucose are derived only from sucrose molecules (DICKERSON, 1972;DICKERSON et al, 1978;POLLARD & DICKERSON, 1984).…”

Section: Resultssupporting

confidence: 80%

Metabolic pathway of oligosaccharides in sorghum honeydew caused by Claviceps africana

Bogo

Mantle

2008

Cienc. Rural

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Section: Resultssupporting

confidence: 80%

Metabolic pathway of oligosaccharides in sorghum honeydew caused by Claviceps africana

Bogo

Mantle

2008

Cienc. Rural

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“…This could be explained by the high concentration of glucan in graminaceous primary cell walls (McNeil et al, 1984). This activity was detected in the rye leaf lesions infected by Claviceps purpurea and was found correlated to the pathogenicity of this fungus (Dickerson et al, 1978).…”

Section: Discussionmentioning

confidence: 97%

Mycosphaerella graminicola produces a range of cell wall-degrading enzyme activities in vitro that vary with the carbon source

et al. 2006

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In this study, two Mycosphaerella graminicola isolates produced a range of cell wall-degrading enzymes (CWDE) in vitro that can potentially degrade wheat cell walls. The influence of three carbon sources on CWDE in vitro production was tested: 1) 1 % galactose (w/v), 2) 1% wheat cell walls (w/v) and 3) a mixture of 1% galactose (w/v) and 1% wheat cell walls (w/v). Six major activities produced by both isolates were detected: xylanase, b-1,3-glucanase, polygalacturonase, cellulase, b-xylosidase and b-galactosidase. Time-course experiments showed that different levels of enzyme activities were obtained with isolates 323 and 94269. These activities levels varied also with the type of carbon source used. Principal Component Analysis showed that the enzyme activities are gathered into two groups. None of the activities of the first group was correlated to the activities of the second group. It also showed that the optimal medium that allowed the production of most of the major activities contained both galactose and wheat cell walls.

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“…Normally, during grass and cereal growth, the stem apex is inaccessible, leaving an unfertilised ovary as the only feasible port of entry, either via the stigma by mimicking pollen tubes or by direct penetration through the ovary wall [27,28]. Biochemical mechanisms for gentle avoidance of the host's wound reaction at the narrow ovary/rachilla junction, involving secretion of β-glucanase and pectinase, have been demonstrated experimentally [29]. Recent speculation [30] concerns somewhat anthropomorphic host-parasite interactions between genomic factors for a perceived 'strict organ specificity' of the rye ovary for C. purpurea attack.…”

Section: Discussionmentioning

confidence: 99%

Comparative Ergot Alkaloid Elaboration by Selected Plectenchymatic Mycelia of Claviceps purpurea through Sequential Cycles of Axenic Culture and Plant Parasitism

Mantle

2020

Biology

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Ergot alkaloids have an established place in plant pathology and toxicology. As pharmaceuticals, their sourcing is via natural or managed agricultural occurrence of sclerotia of Claviceps purpurea (Fr.) Tul. or through industrial fermentation processes with other Claviceps. The key factor for biosynthesis is differentiation of a particular mycelial anatomy. Previous study of these fungi from two disparate English grass genera, Spartina and Phragmites, has shown that only mycelia expressing a plectenchymatic sclerotium-like anatomy in specific axenic culture conditions elaborated ergot alkaloids, and then only as far as lysergic acid. The present report describes sequential cycles of axenic and parasitic cultivation for wild isolates from Dactylis and Alopecurus with intervention of a single ascospore step. This confirms the homozygous character of C. purpurea and defines several potential experimental axenic and parasitic conditions within the species for comparing genomic aspects of partial or full biosynthesis of cyclic tri-peptide alkaloids. Whereas Alopecurus ergot isolates readily parasitized rye, use of Dactylis isolates as inoculum for rye ovaries failed to cause the usual sphacelial fructification but supported growth of exceptionally thin sclerotia, sometimes two in a floret, with low alkaloid content attributed to reduced medullary component. However, after two cycles of axenic and rye-parasitic cultivation, and consistent re-selection of the plectenchymatic character in axenic mycelia, typical growth of ergot sclerotia occurred on rye. Caution thus seems necessary in tests for putative host specificity in any taxonomic realignments within the classical concept of C. purpurea. A Dactylis ergot isolate was also uniquely shown to parasitise the plumule of germinating rye seeds confirming the susceptibility of apical tissues. A key biosynthetic feature of a mycelial glyceride oil, rich in ricinoleic acid, as a prelude to axenic and parasitic formation of ergot alkaloids by C. purpurea is emphasised.

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A rôle for β-glucanases in the parasitism of cereals by Claviceps purpurea

Cited by 15 publications

References 26 publications

Metabolic pathway of oligosaccharides in sorghum honeydew caused by Claviceps africana

Metabolic pathway of oligosaccharides in sorghum honeydew caused by Claviceps africana

Mycosphaerella graminicola produces a range of cell wall-degrading enzyme activities in vitro that vary with the carbon source

Comparative Ergot Alkaloid Elaboration by Selected Plectenchymatic Mycelia of Claviceps purpurea through Sequential Cycles of Axenic Culture and Plant Parasitism

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