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Parasexuality
The parasexual cycle, a process restricted to fungi and single-celled organisms, is a nonsexual mechanism of parasexuality for transferring genetic material without meiosis or the development of sexual structures. It was first described by Italian geneticist Guido Pontecorvo in 1956 during studies on ''Aspergillus nidulans'' (also called ''Emericella nidulans'' when referring to its sexual form, or teleomorph). A parasexual cycle is initiated by the fusion of hyphae (anastomosis) during which nuclei and other cytoplasmic components occupy the same cell (heterokaryosis and plasmogamy). Fusion of the unlike nuclei in the cell of the heterokaryon results in formation of a diploid nucleus (karyogamy), which is believed to be unstable and can produce segregants by recombination involving mitotic crossing-over and haploidization. Mitotic crossing-over can lead to the exchange of genes on chromosomes; while haploidization probably involves mitotic nondisjunctions which randomly reassort ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from the other eukaryotic kingdoms, which by one traditional classification include Plantae, Animalia, Protozoa, and Chromista. A characteristic that places fungi in a different kingdom from plants, bacteria, and some protists is chitin in their cell walls. Fungi, like animals, are heterotrophs; they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Fungi do not photosynthesize. Growth is their means of mobility, except for spores (a few of which are flagellated), which may travel through the air or water. Fungi are the principal decomposers in ecological systems. These and other differences place fungi in a single group of related organisms, named the ''Eumycota'' (''t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somatic (biology)
The term somatic - etymologically from the Ancient Greek words of "σωματικός" (sōmatikós, “bodily”) and σῶμα (sôma, “body”) - is often used in biology to refer to the cells of the body in contrast to the reproductive (germline) cells, which usually give rise to the egg or sperm (or other gametes in other organisms). These somatic cells are diploid, containing two copies of each chromosome, whereas germ cells are haploid, as they only contain one copy of each chromosome (in preparation for fertilisation). Although under normal circumstances all somatic cells in an organism contain identical DNA, they develop a variety of tissue-specific characteristics. This process is called differentiation, through epigenetic and regulatory alterations. The grouping of similar cells and tissues creates the foundation for organs. Somatic mutations are changes to the genetics of a multicellular organism that are not passed on to its offspring through the germline. Most canc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladosporium Fulvum
''Passalora fulva'' is a fungal plant pathogen that causes tomato leaf mold ''Cladosporium fulvum'' is an Ascomycete called '' Passalora fulva'', a non-obligate pathogen that causes the disease on tomato known as the tomato leaf mold.Cladosporium fulvum–Tomato Pathosystem: Fungal Infection Strategy and Plant Responses .... References External links USDA ARS Fungal Database Fungal plant pathogens and diseases Tomato diseases Mycosphaerellaceae Fungi described in 2003 {{fungus-plant-disease-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnaporthe Grisea
''Magnaporthe grisea'', also known as rice blast fungus, rice rotten neck, rice seedling blight, blast of rice, oval leaf spot of graminea, pitting disease, ryegrass blast, Johnson spot, neck blast, wheat blast, and Imochi (Japanese:稲熱) is a plant-pathogenic fungus and model organism that causes a serious disease affecting rice. It is now known that ''M. grisea'' consists of a cryptic species complex containing at least two biological species that have clear genetic differences and do not interbreed. Complex members isolated from ''Digitaria'' have been more narrowly defined as ''M. grisea''. The remaining members of the complex isolated from rice and a variety of other hosts have been renamed ''Magnaporthe oryzae'', within the same ''M. grisea'' complex. Confusion on which of these two names to use for the rice blast pathogen remains, as both are now used by different authors. Members of the ''Magnaporthe grisea'' complex can also infect other agriculturally important cereal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ustilago Scabiosae
''Ustilago'' is a genus of approximately 200 smut fungi parasitic on grasses. Uses ''Ustilago maydis'' is eaten as a traditional Mexican food in many parts of the country, and is even available canned. Farmers have even been known to spread the spores around on purpose to create more of the fungus. It is known in central Mexico by the Nahuatl name huitlacoche. Peasants in other parts of the country call it "hongo de maíz," i.e. "maize fungus." The genome of '' U. maydis'' has beesequenced See also * Corn smut References External links *Ustilago' at Index Fungorum ''Index Fungorum'' is an international project to index all formal names ( scientific names) in the fungus kingdom. the project is based at the Royal Botanic Gardens, Kew, one of three partners along with Landcare Research and the Institute of M ... Ustilaginomycotina Fungal plant pathogens and diseases Basidiomycota genera {{fungus-plant-disease-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudocercosporella Herpotrichoides
''Tapesia yallundae'' is the causal agent for a variety of cereal and forage grass diseases. The anamorph of ''T. yallundae'' is the W-type strain of ''Pseudocercosporella herpotrichoides''. The R-type strain of ''Pseudocercosporella herpotrichoides'' is now known as '' Tapesia acuformis''. Morphology Produces two types of mycelium - one vegetative, yellow-brown, linear, and branching, the other dark and stromalike. Conidiophores are simple or sparingly branched. Conidia (1.5-3.5 x 37-70 μm) are hyaline, curved, and mostly five- to seven-celled. Sclerotia or sclerotialike stromatic mycelium, at first white to yellow-brown but later dark brown, may also be found on the lesions of infected plants. Black apothecia, 0.2 to 0.5 mm of diameter, form at the base of host culms. Apothecium contain cylindric to fusoid asci, of 35 to 38 µm x 5.9 to 7.4 µm. Ascospores are hyaline, fusoid, 0-1 septate, with a rounded end and an average size of 8.9 µm (7. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Verticillium Alboatrum
''Verticillium albo-atrum'' is a plant pathogen with many hosts. Infected plants See: * List of potato diseases * List of alfalfa diseases * List of African daisy diseases * List of beet diseases * List of caneberries diseases * List of tobacco diseases * List of tomato diseases * List of sunflower diseases * List of strawberry diseases * List of sapphire flower diseases * List of rose diseases * List of pocketbook plant diseases * List of Capsicum diseases * List of peanut diseases * List of mint diseases * List of mango diseases * List of Jerusalem cherry diseases * List of impatiens diseases * List of hop diseases * List of hemp diseases * List of geranium diseases * List of fuchsia diseases * List of elm diseases * List of dahlia diseases * List of cucurbit diseases * List of crucifer diseases * List of cineraria diseases * List of chickpea diseases This is a list of diseases of chickpeas (''Cicer arietinum'') Nematodes, parasitic Viral diseases Phytopl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Verticillium Dahliae
''Verticillium dahliae'' is a fungal plant pathogen. It causes verticillium wilt in many plant species, causing leaves to curl and discolor. It may cause death in some plants. Over 400 plant species are affected by ''Verticillium'' complex. Management ''Verticillium dahliae'' has a wide host range and can persist as microsclerotia in the soil for years, so management via fallowing or crop rotation generally has little success. The exception to this is rotation using broccoli, which has been shown to decrease ''Verticillium'' severity and incidence in cauliflower fields. This is likely due to the production of allyl isothiocyanate in broccoli, which can suppress the growth of plant pathogenic fungi. Seed choice may reduce disease presence. Purchasing seed stock from certified ''Verticillium''-free growers and utilizing resistant or partially resistant cultivars can decrease disease incidence. Even resistant cultivars may show symptoms if the field has a high concentration of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penicillium Roqueforti
''Penicillium roqueforti'' is a common saprotrophic fungus in the genus ''Penicillium''. Widespread in nature, it can be isolated from soil, decaying organic matter, and plants. The major industrial use of this fungus is the production of blue cheeses, flavouring agents, antifungals, polysaccharides, proteases, and other enzymes. The fungus has been a constituent of Roquefort, Stilton, Danish blue, Cabrales, Gorgonzola, and other blue cheeses. Other blue cheeses are made with ''Penicillium glaucum''. Classification First described by American mycologist Charles Thom in 1906, ''P. roqueforti'' was initially a heterogeneous species of blue-green, sporulating fungi. They were grouped into different species based on phenotypic differences, but later combined into one species by Kenneth B. Raper and Thom (1949). The ''P. roqueforti'' group got a reclassification in 1996 due to molecular analysis of ribosomal DNA sequences. Formerly divided into two varieties―cheese-maki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fusarium Monoliforme
''Fusarium'' is a large genus of filamentous fungi, part of a group often referred to as hyphomycetes, widely distributed in soil and associated with plants. Most species are harmless saprobes, and are relatively abundant members of the soil microbial community. Some species produce mycotoxins in cereal crops that can affect human and animal health if they enter the food chain. The main toxins produced by these ''Fusarium'' species are fumonisins and trichothecenes. Despite most species apparently being harmless (some existing on the skin as commensal members of the skin flora), some ''Fusarium'' species and subspecific groups are among the most important fungal pathogens of plants and animals. The name of ''Fusarium'' comes from Latin ''fusus'', meaning a spindle. Taxonomy The taxonomy of the genus is complex. A number of different schemes have been used, and up to 1,000 species have been identified at times, with approaches varying between wide and narrow concepts of speciat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nondisjunction
Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division (mitosis/meiosis). There are three forms of nondisjunction: failure of a pair of homologous chromosomes to separate in meiosis I, failure of sister chromatids to separate during meiosis II, and failure of sister chromatids to separate during mitosis. Nondisjunction results in daughter cells with abnormal chromosome numbers (aneuploidy). Calvin Bridges and Thomas Hunt Morgan are credited with discovering nondisjunction in ''Drosophila melanogaster'' sex chromosomes in the spring of 1910, while working in the Zoological Laboratory of Columbia University. Types In general, nondisjunction can occur in any form of cell division that involves ordered distribution of chromosomal material. Higher animals have three distinct forms of such cell divisions: Meiosis I and meiosis II are specialized forms of cell division occurring during generation of gametes (eggs and sperm) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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