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Northern Corn Leaf Blight
Northern corn leaf blight (NCLB) or Turcicum leaf blight (TLB) is a foliar disease of corn (maize) caused by ''Exserohilum turcicum'', the anamorph of the ascomycete ''Setosphaeria turcica''. With its characteristic cigar-shaped lesions, this disease can cause significant yield loss in susceptible corn hybrids. Hosts and symptoms Lesions can eventually expand to a more oblong or “cigar” shape. They may also coalesce to form large areas of necrotic tissue. There are several host-specific forms of ''E. turcicum''. The most economically important host is corn, but other forms may infect sorghum, Johnson grass, or sudangrass. The most common diagnostic symptom of the disease on corn is cigar-shaped or elliptical necrotic gray-green lesions on the leaves that range from one to seven inches long. These lesions may first appear as narrow, tan streaks that run parallel to the leaf veins. Fully developed lesions typically have a sooty appearance during humid weather, as a result of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Corn Leaf Blight
Northern corn leaf blight (NCLB) or Turcicum leaf blight (TLB) is a foliar disease of corn (maize) caused by ''Exserohilum turcicum'', the anamorph of the ascomycete ''Setosphaeria turcica''. With its characteristic cigar-shaped lesions, this disease can cause significant yield loss in susceptible corn hybrids. Hosts and symptoms Lesions can eventually expand to a more oblong or “cigar” shape. They may also coalesce to form large areas of necrotic tissue. There are several host-specific forms of ''E. turcicum''. The most economically important host is corn, but other forms may infect sorghum, Johnson grass, or sudangrass. The most common diagnostic symptom of the disease on corn is cigar-shaped or elliptical necrotic gray-green lesions on the leaves that range from one to seven inches long. These lesions may first appear as narrow, tan streaks that run parallel to the leaf veins. Fully developed lesions typically have a sooty appearance during humid weather, as a result of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sporulation On Leaf
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, fungi and protozoa. Bacterial spores are not part of a sexual cycle, but are resistant structures used for survival under unfavourable conditions. Myxozoan spores release amoeboid infectious germs ("amoebulae") into their hosts for parasitic infection, but also reproduce within the hosts through the pairing of two nuclei within the plasmodium, which develops from the amoebula. In plants, spores are usually haploid and unicellular and are produced by meiosis in the sporangium of a diploid sporophyte. Under favourable conditions the spore can develop into a new organism using mitotic division, producing a multicellular gametophyte, which eventually goes on to produce gametes. Two gametes fuse to form a zygote which develops into a new spo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maize
Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The leafy stalk of the plant produces pollen inflorescences (or "tassels") and separate ovuliferous inflorescences called ears that when fertilized yield kernels or seeds, which are fruits. The term ''maize'' is preferred in formal, scientific, and international usage as a common name because it refers specifically to this one grain, unlike ''corn'', which has a complex variety of meanings that vary by context and geographic region. Maize has become a staple food in many parts of the world, with the total production of maize surpassing that of wheat or rice. In addition to being consumed directly by humans (often in the form of masa), maize is also used for corn ethanol, animal feed and other maize products, such as corn starch and corn s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ascomycota
Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The defining feature of this fungal group is the "ascus" (), a microscopic sexual structure in which nonmotile spores, called ascospores, are formed. However, some species of the Ascomycota are asexual, meaning that they do not have a sexual cycle and thus do not form asci or ascospores. Familiar examples of sac fungi include morels, truffles, brewers' and bakers' yeast, dead man's fingers, and cup fungi. The fungal symbionts in the majority of lichens (loosely termed "ascolichens") such as ''Cladonia'' belong to the Ascomycota. Ascomycota is a monophyletic group (it contains all descendants of one common ancestor). Previously placed in the Deuteromycota along with asexual species from other fungal taxa, asexual (or anamorphic) ascomycetes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Setosphaeria Turcica
''Setosphaeria turcica'' (anamorph ''Exserohilum turcicum''; formerly known as ''Helminthosporium turcicum'') is the causal agent of northern corn leaf blight in maize. It is a serious fungal disease prevalent in cooler climates and tropical highlands wherever corn is grown. It is characterized by large cigar shaped necrotic lesions that develop on the leaves due to the polyketide metabolite monocerin. Races Races of ''S. turcica'' are named for the maize R genes which are not effective against them. For example, the maize gene ''Ht1'' does not confer resistance against a Race 1 isolate, while genes ''Ht2'' and/or ''Ht3'' do. In contrast, genes ''Ht2'' and ''HtN'' do not confer resistance against a Race 2N isolate, while gene ''Ht1'' does. Isolates which do not overcome any known R gene are termed Race 0. Race 1, which overcomes the ''Ht1'' resistance gene, was originally discovered in Hawaii in 1973. By the time it was first noted in the continental United States, in Indiana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conidium
A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non-motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due to the way they are generated through the cellular process of mitosis. The two new haploid cells are genetically identical to the haploid parent, and can develop into new organisms if conditions are favorable, and serve in biological dispersal. Asexual reproduction in ascomycetes (the phylum Ascomycota) is by the formation of conidia, which are borne on specialized stalks called conidiophores. The morphology of these specialized conidiophores is often distinctive between species and, before the development of molecular techniques at the end of the 20th century, was widely used for identification of (''e.g.'' ''Metarhizium'') species. The terms microconidia and macroconidia are sometimes used. Conidiogenesis There are two main types of conidi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stewart's Wilt
Stewart's wilt is a serious bacterial disease of corn caused by the bacterium '' Pantoea stewartii''. This bacterium affects plants, particularly types of maize such as sweet, flint, dent, flour, and popcorn. The disease is also known as bacterial wilt or bacterial leaf blight and has shown to be quite problematic in sweet corn. The disease is endemic in the mid-Atlantic and Ohio River Valley regions and in the southern portion of the Corn Belt. Hosts and symptoms Stewart's wilt can be a serious disease of many corn types, including: sweet, dent, flint, flour, and popcorn. Sweet corn and popcorn cultivars are more susceptible to Stewart's wilt than field (dent) corn, but some dent corn inbreds and hybrids are susceptible. The production of virulence factors can be caused by the communication system between the bacteria known as quorum sensing. Stewart's wilt causes yield reductions by decreasing the size of corn stand or by limiting its production, resulting in fewer and smaller ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Goss's Wilt
''Clavibacter michiganensis'' is an aerobic non-sporulating Gram-positive plant pathogenic actinomycete of the genus ''Clavibacter''. ''Clavibacter michiganensis'' has several subspecies. ''Clavibacter michiganensis'' subsp. ''michiganensis'' causes substantial economic losses worldwide by damaging tomatoes and potatoes.Gartemann et al. "''Clavibacter michiganensis'' subsp. ''michiganensis'': First steps in the understanding of virulence of a Gram-positive phytopathogenic bacterium", ''Journal of Biotechnology'', Germany, 16 July 2003. Retrieved on 2011-10-26. Context ''Clavibacter michiganensis'', also known as Ring Rot, is an unusual genus of phytopathogenic bacteria in that it is gram-positive and does not have a type three secretion system. All ''Clavibacter'' species and subspecies have a type B2γ cell wall crosslinked at a diaminobutyrate residue. ''Clavibacter'' is an aerobic bacterium with a coryneform morphology. There is no mycelium and no spores are produced. '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NCLB Disease Cycle
The No Child Left Behind Act of 2001 (NCLB) was a U.S. Act of Congress that reauthorized the Elementary and Secondary Education Act; it included Title I provisions applying to disadvantaged students. It supported standards-based education reform based on the premise that setting high standards and establishing measurable goals could improve individual outcomes in education. The Act required states to develop assessments in basic skills. To receive federal school funding, states had to give these assessments to all students at select grade levels. The act did not assert a national achievement standard—each state developed its own standards. NCLB expanded the federal role in public education through further emphasis on annual testing, annual academic progress, report cards, and teacher qualifications, as well as significant changes in funding. While the bill faced challenges from both Democrats and Republicans, it passed in both chambers of the legislature with significan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlamydospore
A chlamydospore is the thick-walled large resting spore of several kinds of fungi, including Ascomycota such as '' Candida'', Basidiomycota such as '' Panus'', and various Mortierellales species. It is the life-stage which survives in unfavourable conditions, such as dry or hot seasons. '' Fusarium oxysporum'' which causes the plant disease Fusarium wilt is one which forms chlamydospores in response to stresses like nutrient depletion. Mycelia of the pathogen can survive in this manner and germinate in favorable conditions. Chlamydospores are usually dark-coloured, spherical, and have a smooth (non-ornamented) surface. They are multicellular, with cells connected by pores in the septae between cells. Chlamydospores are a result of asexual reproduction (in which case they are conidia called chlamydoconidia) or sexual reproduction (rare). Teliospores are special kind of chlamydospores formed by rusts and smuts. File:Candida pseudohyphae, chlamydospores, blastospores.png, Pseudo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hokkaido
is Japan's second largest island and comprises the largest and northernmost prefecture, making up its own region. The Tsugaru Strait separates Hokkaidō from Honshu; the two islands are connected by the undersea railway Seikan Tunnel. The largest city on Hokkaidō is its capital, Sapporo, which is also its only ordinance-designated city. Sakhalin lies about 43 kilometers (26 mi) to the north of Hokkaidō, and to the east and northeast are the Kuril Islands, which are administered by Russia, though the four most southerly are claimed by Japan. Hokkaidō was formerly known as '' Ezo'', ''Yezo'', ''Yeso'', or ''Yesso''. Nussbaum, Louis-Frédéric. (2005). "Hokkaidō" in Although there were Japanese settlers who ruled the southern tip of the island since the 16th century, Hokkaido was considered foreign territory that was inhabited by the indigenous people of the island, known as the Ainu people. While geographers such as Mogami Tokunai and Mamiya Rinzō explored the is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Appressorium
An appressorium is a specialized cell typical of many fungal plant pathogens that is used to infect host plants. It is a flattened, hyphal "pressing" organ, from which a minute infection peg grows and enters the host, using turgor pressure capable of punching through even Mylar. Following spore attachment and germination on the host surface, the emerging germ tube perceives physical cues such as surface hardness and hydrophobicity, as well as chemical signals including wax monomers that trigger appressorium formation. Appressorium formation begins when the tip of the germ tube ceases polar growth, hooks, and begins to swell. The contents of the spore are then mobilized into the developing appressorium, a septum develops at the neck of the appressorium, and the germ tube and spore collapse and die. As the appressorium matures, it becomes firmly attached to the plant surface and a dense layer of melanin is laid down in the appressorium wall, except across a pore at the plant interface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
