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First report of Uromyces carthagenensis on Manihot
grahamii (Euphorbiaceae) in Uruguay
Sebastián Martínez Kopp &
Aníbal A. de Carvalho Júnior
Received: 16 March 2011 / Accepted: 7 November 2011 / Published online: 25 November 2011
#Australasian Plant Pathology Society Inc. 2011
Abstract A rust disease was observed on leaves of the
native tree Manihot grahamii in Uruguay. Samples were
collected in ornamental and spontaneous trees in the city of
Florida, Uruguay and the causal agent determined as
Uromyces carthagenensis.Thisisthefirstrecordof
Uromyces carthagenensis in Uruguay.
Keywords Cassava .Pucciniomycota .Rust
The genus Manihot (Euphorbiaceae) contains around 100
species which are native to the Neotropical region (Rogers
and Appan 1973) with Central Brazil having the richest
diversity (Nassar 2000). Manihot species are found mostly
in dry regions and vary in habitat from small trees to shrubs
(Rogers and Appan 1973). Manihot esculenta (cassava) is
the best known species of the genus and is cropped for the
tuberous roots that are used as human and animal feed.
Wild Manihot species have gained importance as these
species may act as sources of alleles which were lost during
domestication of cassava, and that could yield valuable
information for crop improvement (Tanksley and McCouch
1997). Manihot grahamii, is a small tree distributed in SE
South America and the only species of the genus known
from Uruguay where it is known as “falsa mandioca”
(“false cassava”) (Brussa and Grela 2007). This is a
deciduous tree reaching about 7–8 m tall and distributed
in Uruguay in N and NE regions, but naturally regenerated
trees are found in native forest in the south of the country
(Carrere 2007). This tree is used as an ornamental in parks,
streets and gardens and in crafts and musical instruments
(Carrere 2007). During March 2007, a young ornamental
tree of M.grahamii was found with symptoms of rust
infection in a private garden at Florida City, South Uruguay.
Subsequent examinations did not reveal new infections
until 2010. Samples were collected, photographed for
macroscopic characteristics and dried in a plant press.
Dried material was labeled and deposited in the herbaria
MVHC and RB. Specimens were mounted in 85% lactic acid
or aqueous phloxine for light microscopy and examined with a
compound microscope. Following morphological analysis,
the rust species was identified as Uromyces carthagenensis,
which represents a new record for Uruguay. The description
of the Uruguayan specimens is given below.
Taxonomic description
Uromyces carthagenensis Speg., Anales Mus. Nac. Hist.
Nat. Buenos Aires 6: 216. 1899.
Figures 1–6.
Pycnia and aecia not seen. Uredinia on petioles and
lower surface of leaves (Fig. 1), near circular, reddish
brown. Urediniospores ovoid to ellipsoid, 30–40 ×15–
18 μm, wall hyaline to yellowish, verrucose and 1–2μm
thick, with 4 pores, two on each side above the equatorial
region and two below (Figures 2–4). Telia on the lower
surface of leaves (Fig. 1), scattered, erumpent, 2–6mmin
diameter, reddish black to blackish, darker than uredinia.
Teliospores ellipsoid to nearly globose, 30–38×20–26 μm,
with an asymmetrical umbo, lighter in color and up to
S. Martínez Kopp (*)
Laboratorio de Patología Vegetal,
INIA Treinta y Tres, Ruta 8 Km 281,
33000 Treinta y Tres, Uruguay
e-mail: smartinez@tyt.inia.org.uy
A. A. de Carvalho Júnior
Instituto de Pesquisas, Jardim Botânico do Rio de Janeiro,
Pacheco Leão 915,
CEP 22460-030 Rio de Janeiro, RJ, Brazil
Australasian Plant Dis. Notes (2012) 7:9–11
DOI 10.1007/s13314-011-0034-6
10 μm long, external wall hyaline, internal wall reddish
brown and with small verrucae, pedicels hyaline, persistent
and up to 38 μm (Figures 5–6).
Material examined: URUGUAY, FLORIDA, Arroyo
Calleros y Camino a la Macana (S 34° 06′26,5″W56°12′
50,5″), on leaves and petioles of naturally regenerated trees of
Manihot grahamii Hook found in a riparian forest, 17 May
2010, leg. S. Martínez-Kopp (MVHC 5537); Covidef 1 #8,
leaves of M.grahamii, 9 May 2010, S. Martínez-Kopp s. n.
(MVHC 5538, RB), Covidef 1, leaves of M.grahamii,Apr.
2010, leg. S. Martínez-Kopp (MVHC 5539, RB).
This is the first record of Uromyces carthagenensis for
Uruguay. Previously it was only known from Brazil and
Argentina on Manihot sp., M.carthagenensis,M.grahamii,
(recorded under the name M.flabellifolia) and M.tweedi-
ana (Lindquist 1982; Monoson and Prose 1983; Hennen et
al. 2005). This is the third rust species recorded on
Euphorbiaceae in Uruguay. Uromyces euphorbiae (=U.
tordillensis)onEuphorbia ovalifolia and Aecidium detritum
on Phyllanthus sellowianus have been previously recorded
(Herter 1933; Koch et al. 1981). Monoson and Prose (1983)
monographed twenty autoecious Uromyces species on the
new world Euphorbiaceae. They stated that Uromyces
carthagenensis is most similar to U.tolerandus, being
differentiated mostly by the origin of the sculptures and the
appearance in median view of the teliospore. The verrucae
in the teliospores of U.carthagenensis originate internally
in the spore wall giving a sculptured appearance in median
view. The urediniospores can be differentiated by the
number of pores, four in U.carthagenensis with two on
each side (Fig. 4), as described by Lindquist (1982), and
two for U.tolerandus with one above and one below the
equator (Monoson and Prose 1983). Uromyces carthage-
nensis can become and important foliar pathogen for
Figs. 1–6Uromyces carthagenensis: 1. Detail of disease symptom on abaxial leaf surfaces. 2–4. Urediniospores. 2. Median focus. 3. Surface
focus. 4. Showing the germ pores (arrows). 5–6. Teliospores. 5. Median focus. 6. Surface focus
10 S. Martínez Kopp, A.A. de Carvalho Júnior
Manihot grahamii, since this species is increasingly
cultivated as an attractive native ornamental tree.
Acknowledgements Financial aid for some of the work came from
Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do
Rio de Janeiro (FAPERJ—Rio de Janeiro, Brazil) and our Institutions,
Instituto de Pesquisas Jardim Botânico do Rio de Janeiro (JBRJ) and
Facultad de Ciencias, Universidad de la República, Uruguay (past
address of SM). We aknowledge Eduardo Abreo for improvement to
the English text.
References
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First report of Uromyces carthagenensis on Manihot grahamii 11
