Uredinales \Uredinales\, prop. n. pl. (Biol.)
An order of fungi of the phylum Basidiomycota, comprising the
rust fungi.
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The order Uredinales includes between an estimated
5,000 and 7,000 species of diverse plant pathogens.
They have been around since the Carboniferous Age
(250-300 million years ago), and were well established
on the very first ferns. Members of Uredinales are well
enough adapted that they inhabit every continent except
for Antarctica. Commonly known as the "rust fungi,"
they attack nearly all types of plant life, and are
economically devastating to many crops. Members of
Uredinales have a very diverse and complex life
cycle-that may affect more than one host family and
include up to five different stages.
Morphological Features:
Uredinales includes both autoecious and heteroecious
parasites. Autoecious genera infect only one plant
host, while heteroecious genera carry out different
parts of their life cycle on two different hosts. One
example of a heteroecious fungus, Puccinia graminis,
the black stem rust of wheat, requires both the
barberry bush and a grass to complete its complicated
life cycle.
Life cycles of Uredinales are very diverse and complex.
Some genera have up to five stages of their life cycle:
Spermagonia, Aecia, Uredinia, Telia, and Basidia.
Spores are produced in each stage with differing
ploidy: spermatia (n), aeciospores (n+n),
unidiniospores (n+n), teliospores (n+n to 2n), and
basidiospores (n). Genera that do not exhibit all five
of these stages either show three or four instead.
Ecology:
Uredinales comprise the most devastating plant
pathogens of all Basidiomycota. Genera of Uredinales
are responsible for diseases such as: coffee rust,
cedar-apple rust, black stem rust of cereals, carnation
rust, and peanut rust. There are thousands of other
rusts that haven�t been listed that are also
responsible for being seriously detrimental to many
genera of plants.
Despite all of the ecological problems that these fungi
cause to plants, recent efforts have attempted to use
some of these rusts to control weedy pests.
--Kari Jensen (University of Wisconsin, course material)
[available at:
http://botit.botany.wisc.edu/courses/Botany_332/uredinales.html]
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