The oat, sometimes called the common oat, is a species of cereal grain grown for its seed, which is known by the same name. Oats are used for human consumption as oatmeal, including as steel cut oats or rolled oats. They appear to have been domesticated as a secondary crop as their seeds resembled those of other cereals closely enough for them to be included by early cultivators. Oats are a nutrient-rich food associated with lower blood cholesterol and reduced risk of human heart disease when consumed regularly. One of the most common uses of oats is as livestock feed; the crop can also be grown as groundcover and ploughed in as a green manure.
A heteroecious parasite is one that requires at least two hosts. The primary host is the host in which the parasite spends its adult life; the other is the secondary host. Both hosts are required for the parasite to complete its life cycle. This can be contrasted with an autoecious parasite which can complete its life cycle on a single host species. Many rust fungi have heteroecious life cycles:
Rusts are fungal plant pathogens of the order Pucciniales causing plant fungal diseases.
Phytoalexins are antimicrobial substances, some of which are antioxidative as well. They are defined, not by their having any particular chemical structure or character, but by the fact that they are defensively synthesized de novo by plants that produce the compounds rapidly at sites of pathogen infection. In general phytoalexins are broad spectrum inhibitors; they are chemically diverse, and different chemical classes of compounds are characteristic of particular plant taxa. Phytoalexins tend to fall into several chemical classes, including terpenoids, glycosteroids, and alkaloids; however the term applies to any phytochemicals that are induced by microbial infection.
Avena sterilis is a species of grass weed whose seeds are edible. Many common names of this plant refer to the movement of its panicle in the wind.
Avenanthramides are a group of phenolic alkaloids found mainly in oats, but also present in white cabbage butterfly eggs, and in fungus-infected carnation. A number of studies demonstrate that these natural products have anti-inflammatory, antioxidant, anti-itch, anti-irritant, and antiatherogenic activities. Oat kernel extracts with standardized levels of avenanthramides are used for skin, hair, baby, and sun care products. The name avenanthramides was coined by Collins when he reported the presence of these compounds in oat kernels. It was later found that three avenanthramides were the open-ring amides of avenalumins I, II, and III, which were previously reported as oat phytoalexins by Mayama and co-workers.
Stem rust, also known as cereal rust, black rust, red rust or red dust, is caused by the fungus Puccinia graminis, which causes significant disease in cereal crops. Crop species that are affected by the disease include bread wheat, durum wheat, barley and triticale. These diseases have affected cereal farming throughout history. The annual recurrence of stem rust of wheat in North Indian plains was discovered by K.C. Mehta. Since the 1950s, wheat strains bred to be resistant to stem rust have become available. Fungicides effective against stem rust are available as well.
Wheat leaf rust is a fungal disease that affects wheat, barley, rye stems, leaves and grains. In temperate zones it is destructive on winter wheat because the pathogen overwinters. Infections can lead up to 20% yield loss. The pathogen is a Puccinia rust fungus. It is the most prevalent of all the wheat rust diseases, occurring in most wheat-growing regions. It causes serious epidemics in North America, Mexico and South America and is a devastating seasonal disease in India. P. triticina is heteroecious, requiring two distinct hosts.
Lactuca serriola, also called prickly lettuce, milk thistle, compass plant, and scarole, is an annual or biennial plant in the tribe Cichorieae within the family Asteraceae. It has a slightly fetid odor and is commonly considered a weed of orchards, roadsides and field crops. It is the closest wild relative of cultivated lettuce.
The gene-for-gene relationship is a concept in plant pathology that plants and their diseases each have single genes that interact with each other during an infection. It was proposed by Harold Henry Flor who was working with rust (Melampsora lini) of flax (Linum usitatissimum). Flor showed that the inheritance of both resistance in the host and parasite ability to cause disease is controlled by pairs of matching genes. One is a plant gene called the resistance (R) gene. The other is a parasite gene called the avirulence (Avr) gene. Plants producing a specific R gene product are resistant towards a pathogen that produces the corresponding Avr gene product. Gene-for-gene relationships are a widespread and very important aspect of plant disease resistance. Another example can be seen with Lactuca serriola versus Bremia lactucae.
Leaf rust is a fungal disease of barley caused by Puccinia hordei. It is also known as brown rust and it is the most important rust disease on barley.
Puccinia hordei is a species of rust fungus. A plant pathogen, it can cause leaf rust of barley, also known as brown rust of barley. It was originally found on the dry leaves of Hordeum vulgare in Germany.
Barley stripe rust is a fungal disease of barley caused by Puccinia striiformis f. sp. hordei. a forma specialis of Puccinia striiformis. It was first detected in the United States in 1991, in northern and eastern Idaho in 1993, In 1995 it was detected for the first time in western Washington and western Oregon and is currently considered to be well established there. The disease initially develops at a small loci within a field and spreads rapidly and has caused significant losses in areas where climatic conditions are cool and wet.
Ug99 is a lineage of wheat stem rust, which is present in wheat fields in several countries in Africa and the Middle East and is predicted to spread rapidly through these regions and possibly further afield, potentially causing a wheat production disaster that would affect food security worldwide. In 2005 the noted green revolution pioneer Norman Borlaug brought great attention to the problem, and most subsequent efforts can be traced to his advocacy. It can cause up to 100% crop losses and is virulent against many resistance genes which have previously protected wheat against stem rust.
Cochliobolus victoriae is a fungal plant pathogen. It caused the disease called "victoria blight" affecting oats and similar grains.
Setosphaeria turcica 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.
Puccinia coronata is a plant pathogen and causal agent of oat and barley crown rust. The pathogen occurs worldwide, infecting both wild and cultivated oats. Crown rust poses a threat to barley production, because the first infections in barley occur early in the season from local inoculum. Crown rusts have evolved many different physiological races within different species in response to host resistance. Each pathogenic race can attack a specific line of plants within the species typical host. For example, there are over 290 races of P. coronata. Crops with resistant phenotypes are often released, but within a few years virulent races have arisen and P. coronata can infect them.
Plant disease resistance protects plants from pathogens in two ways: by pre-formed structures and chemicals, and by infection-induced responses of the immune system. Relative to a susceptible plant, disease resistance is the reduction of pathogen growth on or in the plant, while the term disease tolerance describes plants that exhibit little disease damage despite substantial pathogen levels. Disease outcome is determined by the three-way interaction of the pathogen, the plant and the environmental conditions.
Wheat yellow rust, also known as wheat stripe rust, is one of the three major wheat rust diseases, along with stem rust of wheat and leaf rust.
