Mycelium

About: Mycelium is a research topic. Over the lifetime, 8923 publications have been published within this topic receiving 170993 citations.

VdNEP, an Elicitor from Verticillium dahliae, Induces Cotton Plant Wilting

Abstract: Verticillium wilt is a vascular disease of cotton. The causal fungus, Verticillium dahliae, secretes elicitors in culture. We have generated approximately 1,000 5'-terminal expressed sequence tags (ESTs) from a cultured mycelium of V. dahliae. A number of ESTs were found to encode proteins harboring putative signal peptides for secretion, and their cDNAs were isolated. Heterologous expression led to the identification of a protein with elicitor activities. This protein, named V. dahliae necrosis- and ethylene-inducing protein (VdNEP), is composed of 233 amino acids and has high sequence identities with fungal necrosis- and ethylene-inducing proteins. Infiltration of the bacterially expressed His-VdNEP into Nicotiana benthamiana leaves resulted in necrotic lesion formation. In Arabidopsis thaliana, the fusion protein also triggered production of reactive oxygen species and induced the expression of PR genes. When added into suspension cultured cells of cotton (Gossypium arboreum), the fusion protein elicited the biosynthesis of gossypol and related sesquiterpene phytoalexins at low concentrations, and it induced cell death at higher concentrations. On cotton cotyledons and leaves, His-VdNEP induced dehydration and wilting, similar to symptoms caused by a crude preparation of V. dahliae elicitors. Northern blotting showed a low level of VdNEP expression in the mycelium during culture. These data suggest that VdNEP is a wilt-inducing factor and that it participates in cotton-V. dahliae interactions.

A new hypothesis to explain allocation of dry matter between mycorrhizal fungi and pine seedlings in relation to nutrient supply

Abstract: Nutrient uptake by forest trees is largely dependent on their associated ectomycorrhizal fungi. The presence of extramatrical mycelium produced by ectomycorrhizal fungi allows trees to exploit a larger soil volume. In this paper the effects of macronutrients on the production of extramatrical mycelium are reviewed. It is concluded that elevated levels of nitrogen and, to some extent, phosphorus strongly inhibit the development of extramatrical mycelium. A deficiency of phosphorus, on the other hand, stimulates ectomycorrhizal development. Low levels of phosphorus may offset the negative influence of nitrogen, indicating that the nitrogen effect is indirect. No other macronutrients have been shown to affect extramatrical mycelium significantly, however, very few studies have been made.

Anti-tumor polysaccharide from the mycelium of liquid-cultured Agaricus blazei mill.

Abstract: SUMMARY: Anti-tumor active polysaccharide against Sarcoma 180 was isolated by DEAESepharose CL-6B and Sepharose 4B column chromatography from the hot-water soluble fraction of the mycelium of liquid-cultured Agaricus blazei mill. This polysaccharide did not react with antibodies of anti-tumor polysaccharides such as lentinan, gliforan, and FIII-2-b which is one of anti-tumor polysaccharides from Agaricus blazei. Moreover, the analyses of 13C-NMR and GC-MS suggested that this polysaccharide was preliminarily glucomannan with a main chain of [g-l,2-1inked D-mannopyranosyl residues and 13-D-glucopyranosyl-3-O13-D-glucopyranosyl residues as a side chain. This polysaccharide was completely different from the anti-tumor polysaccharide from fruiting body ofAgaricus blazei, ~-1,6-glucan.