Telium

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Close-up of Gymnosporangium clavariiforme telia emerging from Juniperus communis bark Gymnosporangium telia macro IMGP0418.jpg
Close-up of Gymnosporangium clavariiforme telia emerging from Juniperus communis bark
Micrograph of two teliospores from telia of Gymnosporangium clavariiforme Teliospores 0433.jpg
Micrograph of two teliospores from telia of Gymnosporangium clavariiforme

Telium, plural telia, are structures produced by rust fungi as part of the reproductive cycle. [1] They are typically yellow or orange drying to brown or black and are exclusively a mechanism for the release of teliospores which are released by wind or water to infect the alternate host in the rust life-cycle. The telial stage provides an overwintering strategy in the life cycle of a parasitic heteroecious fungus by producing teliospores; this occurs on cedar trees. A primary aecial stage is spent parasitizing a separate host plant which is a precursor in the life cycle of heteroecious fungi. Teliospores are released from the telia in the spring. The spores can spread many kilometers through the air, however most are spread near the host plant. [2]

Contents

Host plants

There are a number of plants that can be infected by the telial stage. Therefore, the telial stage is considered a pathogen to those plants. A few specific plant pathogenic species are listed here with their hosts.

  1. Puccinia graminis or known commonly as black stem rust. It infects many different cereal crops.
  2. Gymnosporangium juniperi-virginianae . It infects the eastern red cedar. [3] This is shown to the right.
  3. Gymnosporangium sabinae . It infects pear trees.

Spore stages

The life cycle of rust fungi can have up to five different spore stages and can get quite complex. [4] These stages are:

Related Research Articles

<i>Gymnosporangium</i> Genus of fungi

Gymnosporangium is a genus of heteroecious plant-pathogenic fungi which alternately infect members of the family Cupressaceae, primarily species in the genus Juniperus (junipers), and members of the family Rosaceae in the subfamily Amygdaloideae. The common name cedar-apple rusts has been used for these fungi. According to the Dictionary of the Fungi, there are about 57 species in the genus.

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:

<span class="mw-page-title-main">Rust (fungus)</span> Order of fungi

Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales.

<i>Cronartium ribicola</i> Species of rust fungus

Cronartium ribicola is a species of rust fungus in the family Cronartiaceae that causes the disease white pine blister rust. Other names include: Rouille vésiculeuse du pin blanc pin (French), white pine Blasenrost (German), moho ampolla del pino blanco (Spanish).

<span class="mw-page-title-main">Stem rust</span> Cereal disease on wheat, barley, oats...

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 Prof. 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.

<span class="mw-page-title-main">Teliospore</span>

Teliospore is the thick-walled resting spore of some fungi, from which the basidium arises.

<i>Gymnosporangium globosum</i> Species of fungus

Gymnosporangium globosum is a fungal plant pathogen that causes cedar-hawthorn rust.

<i>Gymnosporangium juniperi-virginianae</i> Species of fungus

Gymnosporangium juniperi-virginianae is a plant pathogen that causes cedar-apple rust. In virtually any location where apples or crabapples (Malus) and Eastern red cedar coexist, cedar apple rust can be a destructive or disfiguring disease on both the apples and cedars. Apples, crabapples, and eastern red cedar are the most common hosts for this disease. Similar diseases can be found on Quince and hawthorn and many species of juniper can substitute for the eastern red cedars.

<i>Puccinia asparagi</i> Species of fungus

Puccinia asparagi is the causative agent of asparagus rust. It is an autoecious fungus, meaning that all stages of its life cycle – pycniospores, aeciospores, and teliospores – all develop upon the same host plant . Rust diseases are among the most destructive plant diseases, known to cause famine following destruction of grains, vegetables, and legumes. Asparagus rust occurs wherever the plant is grown and attacks asparagus plants during and after the cutting season. Asparagus spears are usually harvested before extensive rust symptoms appear. Symptoms are first noticeable on the growing shoots in early summer as light green, oval lesions, followed by tan blister spots and black, protruding blisters later in the season. The lesions are symptoms of Puccinia asparagi during early spring, mid-summer and later summer to fall, respectively. Severe rust infections stunt or kill young asparagus shoots, causing foliage to fall prematurely, and reduce the ability of the plant to store food reserves. The Puccinia asparagi fungus accomplishes this by rust lowering the amounts of root storage metabolites. The infected plant has reduced plant vigor and yield, often leading to death in severe cases. Most rust diseases have several stages, some of which may occur on different hosts; however, in asparagus rust all the life stages occur on asparagus. Because of this, many observers mistake the different stages of the Puccinia asparagi life cycle as the presence of different diseases. The effects of Puccinia asparagi are present worldwide wherever asparagus is being grown. Asparagus rust is a serious threat to the asparagus industry.

<i>Puccinia coronata</i> Species of fungus

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.

<i>Gymnosporangium sabinae</i> Species of fungus

Gymnosporangium sabinae is a fungal heteroecious plant pathogen with Juniperus as the primary (telial) host and only Pyrus as secondary (aecial) hosts. It is one of many types of rust fungi affecting plants.

<i>Puccinia horiana</i> Species of fungus

Puccinia horiana is a species of fungus that causes chrysanthemum white rust, is a disease of plant species of the genus Chrysanthemum.

<i>Puccinia poarum</i> Species of fungus

Puccinia poarum, the coltsfoot gall rust or meadow grass rust, is a plant pathogen. This fungal parasite forms a yellow to orange gall, 1–2 cm in diameter, on the underside of leaves of coltsfoot. It also infects, but does not gall grasses of the family Poaceae. P. poarum is a genetically diverse species that has been reported on at least seventy plant hosts.

Ruth Florence Allen (1879–1963) was an American botanist and plant pathologist and the first woman to earn her Ph.D. in botany from the University of Wisconsin. Her doctorate research focused on the reproduction and cell biology of ferns, particularly the phenomenon of apogamy. Later in her career, Allen shifted her focus to plant pathology. Her major contribution to the field of mycology was furthering the understanding of rust fungi, a group of economically important plant pathogens. Allen completed many studies on Puccinia graminis, once considered a catastrophically damaging disease-causing agent in cereal crops before the discovery of current management measures.

<i>Gymnosporangium clavariiforme</i> Species of fungus

Gymnosporangium clavariiforme is a species of rust fungus which alternately infects Juniperus and hawthorns.

Spruce broom rust or yellow witches' broom rust is a fungal plant disease caused by the basidiomycete fungus known as Chrysomyxa arctostaphyli. It occurs exclusively in North America, with the most concentrated outbreaks occurring in northern Arizona and southern Colorado on blue and Engelmann spruce, as well as in Alaska on black and white spruce. This disease alternates its life cycle between two hosts, with the spruce serving as the primary host and bearberry serving as the secondary or alternate host. The name for the disease comes from the distinctive “witches broom”, commonly yellow in color, which forms on the spruce after young needles have been infected. Management must be carried out through physical or mechanical methods, such as the pruning of brooms or the removal of the secondary host from the area, because no chemical control measures have yet been determined to be economically effective. Generally, spruce broom rust is seen as a mostly cosmetic issue, and it is very rarely the direct cause of tree death; however, research has shown a reduction in overall productivity and health of infected trees, making it an important issue for logging and timber companies.

Puccinia libanotidis, common name moon carrot rust, is a species of rust that infects the moon carrot, Seseli libanotis. It is restricted to the same range as its host plant across Eurasia.

Phakopsora euvitis is a rust fungus that causes disease of grape leaves. This rust fungus has been seen in regions including: Eastern Asia, Southern Asia, Southwestern Brazil, the Americas, and northern Australia. It is widely distributed in eastern and southern Asia but was first discovered on grapevines in Darwin, Australia in 2001 and was identified as Asian grapevine leaf rust by July 2007.

<i>Puccinia sorghi</i> Common rust of maize/corn fungal disease

Puccinia sorghi, or common rust of maize, is a species of rust fungus that infects corn and species from the plant genus Oxalis.

<i>Cronartium quercuum</i> Fungal disease of pine and oak trees

Cronartium quercuum, also known as pine-oak gall rust is a fungal disease of pine and oak trees. Similar to pine-pine gall rust, this disease is found on pine trees but its second host is an oak tree rather than another pine.

References

  1. Brand g, Brand R & Shattock R,.Sorting out Gymnosporangium species - the aecial stage, October 2006, Field Mycology Volume 7(4)
  2. Brand, A.W. et al. 2004. The Other Half: The telial stage of the rust fungus Gymnosporangium confusum. Field Mycology. Vol 5:14-16
  3. Volk, T.J. Tom Volk's Fungus of the Month for May 1999. University of Wisconsin La Crosse. http://botit.botany.wisc.edu/toms_fungi/may99.html, December 5, 2010
  4. Schumann, G.L. et al. 2010. Essential Plant Pathology. American Phytopathological Society. Second Edition. St. Paul. pp. 43–44