Mycelium

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

The fatty acid composition of sporangiospores and vegetative mycelium of temperature-adapted fungi in the order mucorales.

Abstract: SUMMARY: The lipid content and fatty acid composition of sporangiospores and vegetative mycelium of mesophilic, thermotolerant and thermophilic fungi in the Mucorales were examined. In each fungus the spores contained less lipid than the vegetative mycelium. The mesophiles accumulated less lipid in spores and mycelium than did thermotolerants and thermophiles. No unusual fatty acids were detected by gas-liquid chromatography in the lipids of spores or mycelium. The fatty acid compositions of spores and vegetative mycelium were qualitatively very similar, but spore lipids were always more highly saturated than mycelial lipids. Lowering growth temperature from 48 to 25° increased the synthesis of unsaturated fatty acids in the spores and the mycelium of the thermotolerant and thermophilic fungi examined.

Antagonism of Trichoderma viride and effects of extracted water soluble compounds from Trichoderma species and benlate solution on Ceratocystis paradoxa

Abstract: Trichoderma viride was identified as a mycoparasite against Ceratocystis paradoxa. When grown near the pathogen, T. viride was seen entwining around the pathogen mycelium. It was stimulated to produce branches that grew directly to the pathogen mycelium. Firm attachment on the pathogen conidia resulted in the penetration and successful growth of T. viride. Some of the impregnated C. paradoxa were found death. Benlate solution and extracted water-soluble compounds from Trichoderma species were evaluated for the control of C. paradoxa. Trichoderma polysporum significantly reduced the growth of C. paradoxa at high concentrations (100% and 70%) followed by T. viride, T. hamatum, T. aureoviride and benlate solution recorded average performances. At (50, 30 and 10%) low concentrations, they all recorded poor performances. Minimum inhibitory concentration by T. viride was 10%, T. polysporum 25%, T. hamatum and T. aureoviride were 30% each, and benlate solution remained 50%. T. polysporum exhibited better control of the pathogen when compared with other extracted water soluble compounds from Trichoderma species and benlate solution.

Tobacco leaf spot and root rot caused by Rhizoctonia solani Kühn

Abstract: SUMMARY Rhizoctonia solani Kuhn is a soil-borne fungal pathogen that causes disease in a wide range of plants worldwide. Strains of the fungus are traditionally grouped into genetically isolated anastomosis groups (AGs) based on hyphal anastomosis reactions. This article summarizes aspects related to the infection process, colonization of the host and molecular mechanisms employed by tobacco plants in resistance against R. solani diseases. Taxonomy: Teleomorph: Thanatephorus cucumeris (Frank) Donk; anamorph: Rhizoctonia solani Kuhn; Kingdom Fungi; Phylum Basidiomycota; Class Agaricomycetes; Order Cantharellales; Family Ceratobasidiaceae; genus Thanatephorus. Identification: Somatic hyphae in culture and hyphae colonizing a substrate or host are first hyaline, then buff to dark brown in colour when aging. Hyphae tend to form at right angles at branching points that are usually constricted. Cells lack clamp connections, but possess a complex dolipore septum with continuous parenthesomes and are multinucleate. Hyphae are variable in size, ranging from 3 to 17 µm in diameter. Although the fungus does not produce any conidial structure, ellipsoid to globose, barrel-shaped cells, named monilioid cells, 10–20 µm wide, can be produced in chains and can give rise to sclerotia. Sclerotia are irregularly shaped, up to 8–10 mm in diameter and light to dark brown in colour. Disease symptoms: Symptoms in tobacco depend on AG as well as on the tissue being colonized. Rhizoctonia solani AG-2-2 and AG-3 infect tobacco seedlings and cause damping off and stem rot. Rhizoctonia solani AG-3 causes ‘sore shin’ and ‘target spot’ in mature tobacco plants. In general, water-soaked lesions start on leaves and extend up the stem. Stem lesions vary in colour from brown to black. During late stages, diseased leaves are easily separated from the plant because of severe wilting. In seed beds, disease areas are typically in the form of circular to irregular patches of poorly growing, yellowish and/or stunted seedlings. Resistance: Knowledge is scarce regarding the mechanisms associated with resistance to R. solani in tobacco. However, recent evidence suggests a complex response that involves several constitutive factors, as well as induced barriers controlled by multiple defence pathways. Management: This fungus can survive for many years in soil as mycelium, and also by producing sclerotia, which makes the management of the disease using conventional means very difficult. Integrated pest management has been most successful; it includes timely fungicide applications, crop rotation and attention to soil moisture levels. Recent developments in biocontrol may provide other tools to control R. solani in tobacco.

Discaria trinervis - Frankia symbiosis promotion by saprophytic actinomycetes.

Abstract: The influence of saprophytic actinomycetes strains on the Discaria trinervis - Frankia actinorhizal symbiosis was investigated. Three strains out of 122 isolated from the rhizosphere and rhizoplane of D. trinervis with multiple enzymatic activities, were selected for plant growth experiments: Streptomyces (BCRU-MM40), Actinoplanes (BCRU-ME3) and Micromonospora (BCRU-MM18). Inoculated seedlings of Discaria trinervis were grown in glass tubes with vermiculite-sand for 12 weeks. They were inoculated either with a single saprophytic strain or a combination of one or two of them together with the symbiotic N(2) fixing strain Frankia BCU110501. The saprophytic strains were applied in two experimental series, i.e. mycelium + supernatant simultaneously or mycelium and supernatant (growth medium free of cells) separately. Micromonospora strain MM18 showed a direct promotion effect on shoot growth, when plants were inoculated with mycelium and supernatant together. Streptomyces strain MM40 and Actinoplanes strain ME3 promoted the actinorhizal symbiosis with Frankia and consequently the development of plant shoots, when supernatant was involved as inoculum. It is supposed, that the strains MM18, MM40 and ME3 produce bioactive metabolites, which are released into the culture medium. The saprophytic strains studied could be considered as "promoting or helper rhizoactinomycetes" of the actinorhizal plant D. trinervis.