What is sclerotia in plants?
Sclerotinia sclerotiorum is a plant pathogenic fungus and can cause a disease called white mold if conditions are conducive. S. sclerotiorum can also be known as cottony rot, watery soft rot, stem rot, drop, crown rot and blossom blight.
What do the sclerotia play in the plant disease life cycle?
Ascospores of Sclerotinia spp. infect upper portions of plants to cause diseases such as flower blights, stem rots, fruit rots, and head blight. Initially, lesions appear as water-soaked spots that expand irregularly and indeterminately. As the lesions enlarge, affected stems may be girdled (Fig.
What fungus forms sclerotia?
Examples of fungi that form sclerotia are ergot (Claviceps purpurea), Polyporus tuberaster, Psilocybe mexicana, Sclerotium delphinii and many species in Sclerotiniaceae. Although not fungal, the plasmodium of slime molds can form sclerotia in adverse environmental conditions.
How do you control Sclerotium rolfsii?
Management systems that can reduce the disease severity include the following:
- Ensure plant residues have decomposed before planting.
- Deep ploughing soil to bury host debris and sclerotia is a useful measure.
- Include non-susceptible crops such as maize and small grains in rotations to reduce inoculum levels in soil.
How is sclerotia formed?
Sclerotial development sometimes occurs when nutrients are running out, but many are formed in active cultures showing that there are other stimuli for the growth of these structures. Their development involves the repeated branching of hyphae and formation of closely spaced septa.
What is the function of Rhizomorph?
rhizomorph, a threadlike or cordlike structure in fungi (kingdom Fungi) made up of parallel hyphae, branched tubular filaments that make up the body of a typical fungus. Rhizomorphs act as an absorption and translation organ of nutrients.
What is damping off in plants?
Damping off is a disease of seedlings Quite often a large section or an entire tray of seedlings is killed. Visible damping off fungus growing on an emerging seedling. Once plants have mature leaves and a well developed root system, they are better able to naturally resist the fungus or mold that causes damping off.
How many fungi make sclerotia?
We found that sclerotium-forming fungi are ecologically diverse and phylogenetically dispersed among 85 genera in 20 orders of Dikarya, suggesting that the ability to form sclerotia probably evolved ≥14 different times in fungi.
Which type of spores is produced by Sclerotium rolfsii?
A. rolfsii produces basidia on an exposed hymenium and basidia produce four haploid basidiospores. The appressed hymenium develops in small, thin, irregular patches.
What is sclerotium gum?
Sclerotium gum is a naturally derived, gel-like polysaccharide (sugar-based) ingredient. It is produced from the fermentation of Sclerotium rolfsii, a type of fungus that gives it its name. Sclerotium gum is used in cosmetics to thicken and stabilize formulas. It also functions as a skin conditioning agent.
What is Chlamydospores in fungi?
Chlamydospores are produced by many fungi and represent enlarged, thick-walled vegetative cells with varied forms and condensed cytoplasm that form within hyphae or at hyphal tips.
What is Rhizomorph in microbiology?
rhizomorph, a threadlike or cordlike structure in fungi (kingdom Fungi) made up of parallel hyphae, branched tubular filaments that make up the body of a typical fungus. Rhizomorphs act as an absorption and translation organ of nutrients. rhizomorph.
What is the physiology of Sclerotium rolsfsii?
The physiology of Sclerotium rolsfsii is characterized by its ability to form sclerotia consisting of compact hyphal aggregates that form on nutrient-depleted media. 3–5 The sclerotia ensure survival and dissemination of the fungus.
What is the pathogenesis of S rolfsii?
S. rolfsii is a necrotrophic soil borne plant pathogen, killing plant tissues in advance of colonization by production of oxalic acid and cell-wall degrading enzymes. It survives as sclerotia in soil and as mycelium in crop debris. Sclerotia are known to survive several years in the absence of a host.
Is Sclerotium rolfsii a Kudzu?
Sclerotium rolfsii Sacc. : ‘Kudzu of the Fungal World’ Sclerotium rolfsii, an omnivorous, soilborne fungal pathogen, causes disease on a wide range of agricultural and horticultural crops. Although no worldwide compilation of host genera has been published, over 270 host genera have been reported in the United States alone.
What are the characteristics of sclerotia?
Mature sclerotia are hard, slightly pitted, and have a distinct rind. Although most sclerotia are spherical, some are slightly flattened or coalesce with others to form an irregular sclerotium. S. rolfsii does not form asexual fruiting structures or spores.