Introduction to Fungi, Third Edition

PUCCINIA AND UROMYCES
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Fig 22.13 Teliospores of rust fungi belonging to the Pucciniaceae sensu Dietel. (a) Puccinia coronata.Notethe‘crown’ofspine-like
wall extensions at the teliospore apex. (b) Uromyces appendiculatus.The teliospore is one-celled. (c,d) Phragmidium mucronatum.
(c) Teliospore freshly mounted in water. (d) Spore after about15 min in water.The base of the pedicel has broken, exuding a
large amount of mucilage which has been made visible by replacing the water with dilute Indian ink. (e) Triphragmium ulmariae.
The teliospore is three-celled. (f) Gymnosporangiumfuscum. Note the long teliospore stalk. (a,b,e) to same scale; (c,d) to same scale.
remains have been found in Israel (Kislev, 1982).
The centre of origin of P. triticina and its aecial
host, Thalictrum, is probably also in the Western
Mediterranean, as is that of Puccinia striiformis.
Rhamnus and wild oats are common in Israel,
as is P. mesnieriana, suggesting that this is where
P. coronata may have its origin. Wild barley
species, especially Hordeum spontaneum, are also
very common in Israel and adjacent countries
where barley has been cultivated since the
dawn of agriculture. Since the alternate host of
P. hordei, Ornithogalum, is also found there and is
profusely infected, this region may be where
P. hordei evolved.
22.5 Puccinia and Uromyces
The genus Puccinia is by far the largest among
the Uredinales, comprising about 4000 species
(Kirk et al., 2001). The most readily recognized
characteristic is the teliospore which usually
contains two darkly pigmented cells borne on
a thin hyaline stalk. Puccinia spp. are pathogenic
mainly on Angiosperms, and especially on
grasses as principal hosts. The genus Uromyces
(about 800 spp.) is similar in appearance to
Puccinia, differing mainly in its teliospore, which
is commonly one-celled (Fig. 22.13b). Several
Puccinia spp. also produce a certain proportion
of one-celled teliospores (called mesospores) in
their telia, and it is therefore easy to imagine how
the one-celled teliospore of Uromyces could have
evolved. DNA sequencing data support a close
relationship between the genera Puccinia and
Uromyces (Maier et al., 2003).
22.5.1 Other common Puccinia spp.
Puccinia sorghi was so named because Schweinitz,
when he first described it, erroneously believed