Mycol. Res. 108 (7): 846–848 (July 2004). f The British Mycological Society
846
DOI: 10.1017/S0953756204000681 Printed in the United Kingdom.
Aecidium kalanchoe sp. nov., a new rust on
Kalanchoe blossfeldiana (Crassulaceae)
José R. HERNÁDEZ1*, M. Catherine AIME1 and Brad NEWBRY2
1
USDA/ARS, Systematic Botany and Mycology Laboratory, 10300 Baltimore Avenue, Beltsville, MD 20705-2350, USA.
Idaho State Department of Agriculture, Plant Industry Division, 434 Shoshone Street West, Twin Falls, ID 83301, USA.
E-mail : jose@nt.ars-grin.gov
2
Received 13 February 2004; accepted 26 May 2004.
A rust fungus found on cultivars of Kalanchoe blossfeldiana (Crassulaceae) is described as a new species, Aecidium
kalanchoe sp. nov., and compared to the other described rusts on members of the Crassulaceae. Only one other rust is
known to parasitize Kalanchoe spp. A DNA sequence of A. kalanchoe suggests that the teleomorph is related to Puccinia.
INTRODUCTION
Plants of Kalanchoe blossfeldiana (Crassulaceae ; syn.
Kalanchoe globulifera var. coccinea) growing in a
greenhouse in Idaho were found to be parasitized by
a rust fungus. Kalanchoe blossfeldiana, ‘Christmas
kalanchoe’, is native to Madagascar. It is grown extensively in the USA and Europe as a prized perennial that
has succulent leaves and bears yellow, orange, red, pink
and purple flowers. Plants of K. blossfeldiana are often
propagated in greenhouses in Costa Rica and are imported as small plants usually in spring for sale and
distribution throughout North America. Although a
number of diseases are known on K. blossfeldiana and
other cultivated species of Kalanchoe (Daughtrey et al.
1995), only one rust fungus, Aecidium umbilici Trott.
1901, has previously been described on this plant genus.
The rust on plants from Idaho is unlike A. umbilici nor
does it fit the description of any of the sixteen other
species of Uredinales previously reported on Crassulaceae, thus it is described as a new species.
TAXONOMY
Aecidium kalanchoe J. R. Hern., sp. nov.
(Figs 1–6)
Spermogonia subepidermalia, typus 4, pertinentes, badia
punctia facientes, circumcincta aeciis. Aecia amphigenia, ad
0.2 mm lata, ad 1.2 mm longa, cylindrica, laceratescentes,
lutea. Cellula peridialia 21.5–33r14–24 mm, parietibus
2.5–3 mm, hyalinis. Aeciosporae catenulatae, sphaeroideae,
* Corresponding author.
ovoideae-obovoideae, 19–27r16.5–22 mm, minute verrucosae. Uredinia et telia incognita.
Typus: USA : Idaho: Twin Falls County, Buhl, on living
leaves of Kalanchoe blossfeldiana cv. ‘Colbuco ’, 7 May 2003,
E. K. Vavricka (BPI 843633 – holotypus). [DNA sequence of
the nLSUrDNA deposited in GenBank, accession no.
AY463163.]
Spermogonia subepidermal, type 4, appearing as
chestnut-brown dots, surrounded by aecia. Aecia in
chlorotic, circular lesions that measure 1–1.5 cm diam,
forming concentric circles around spermogonia, amphigenous, to 0.2 mm wide and 1.2 mm long, cylindrical,
becoming lacerate, yellowish orange. Peridial cells
21.5–33r14–24 mm, walls 2.5–3 mm thick, hyaline,
polyhedral or shield-shaped, outer surface densely and
minutely verrucose, inner surface striate verrucose.
Aeciospores catenulate, sphaeroid, ovoid to obovoid,
19–27r16.5–22 mm, minutely verrucose, contents yellowish, wall 1–2 mm thick, hyaline. Uredinia and telia
unknown.
Specimens of Aecidium umbilici examined : Portugal : São
Fiel, on Umbilicus erectus, April 1903, C. Torrend (BPI
153538) ; São Fiel near Castello Branco, on U. rupestris, April
1901, C. Zimmermann (BPI 153539).
DISCUSSION
About 20 plants of Kalanchoe blossfeldiana growing in
a greenhouse in Idaho were infected with Aecidium
kalanchoe. Infected plants gradually shed the affected
leaves. Although several cultivars of this species were
growing together, only two (cvs ‘Sofie ’ and ‘Colbuco ’)
J. R. Hernández, M. C. Aime and B. Newbry
847
Figs 1–6. Aecidium kalanchoe on Kalanchoe blossfeldiana. Fig. 1. Chlorotic leaf spot with concentrically arranged aecia.
Fig. 2. Cylindric aecia. Fig. 3. Densely and minutely verrucose outer surface of peridial cells. Fig. 4. Striate verrucose
inner surface of peridial cells. Fig. 5. Aeciospores. Fig. 6. Spermogonium. Bars: Fig. 1=25 mm ; Fig. 2=1 mm ;
Figs 3–5=20 mm; and Fig. 6=30 mm.
were infected. All of the plants of Kalanchoe had been
propagated in Costa Rica prior to being relocated to
Idaho.
The only other rust reported on a species of Kalanchoe is Aecidium umbilici, known from K. marmorata
(Canonaco 1936). A. umbilici was originally described
on Umbilicus erectus (Crassulaceae), a plant native to
Europe and the eastern Mediterranean. A. kalanchoe
differs from A. umbilici in the size and shape of both the
aecia and aeciospores. Based on the specimens examined, aecia of A. umbilici are short, less than 0.5 mm
tall, while those of A. kalanchoe are cylindrical, and to
Aecidium kalanchoe sp. nov. on Kalanchoe
1.2 mm tall. Aeciospores of A. umbilici are ovoid
to elongate, 18–25 (–34)r20–23 mm with cell walls
2–2.5 mm thick, while those of A. kalanchoe are sphaeroid, ovoid to obovoid, 19–27r16.5–22 mm, with cell
walls 1–2 mm thick. A. umbilici is known from Africa,
Italy, Portugal and Norway (Farr et al. 2003).
In addition to A. umbilici, several other rust fungi
that produce aecia are known on hosts in the Crassulaceae. Puccinia australis Koern 1873 (Cummins 1971)
that produces its aecial stage (A. erectum) on Sedum
is characterized by polyhedric aeciospores that are
smaller (18–20r16–18 mm) than those of A. kalanchoe.
Puccinia longissima Schroet. 1879 (syn. Aecidium sedi)
systemically infects species of Sedum and Rhodiola
(Cummins 1971) and has larger aeciospores, (22)–
24–27 (–31)r(18–) 21–24 (–26) mm, with thicker cell
walls (2–3 mm thick). P. sedi-triseti Dupias 1971 (Dupias
1971) on Sedum produces aecia that are caulicolous
or distributed on the leaves. The aeciospores of
P. sedi-triseti (21–28r18–22 mm) are similar in size to
those of A. kalanchoe, however, they have ten germ
pores while none were observed in aeciospores of
A. kalanchoe. A. sedi-aizoontis Tranzschel 1910 on
Sedum (Saccardo 1925) also has aeciospores with conspicuous germ pores and a thick cell wall up to 5 mm.
Uromyces sedi Gäum. 1954 (Gäumann 1954) and
Caeoma sedi Azbukina 1970 (Azbukina 1970) produce
Caeoma-like aecia, whereas in A. kalanchoe the aecia
are aecidioid.
A number of other rust fungi have been observed on
Crassulaceae but have no known aecial stage. Puccinia
umbilici Guépin ex Duby 1830 (Hiratsuka et al. 1992) is
commonly reported on various genera of the Crassulaceae including Cotyledon, Sedum and Umbilicus in
Europe, Japan, and the USA (Farr et al. 2003). P.
benkei Kusano 1904 is known on Sedum (Crassulaceae)
in Japan (Hiratsuka et al. 1992). P. umbilicicola Gjaerum & Bahcecioglu 2003 was described from U. erectus
in Turkey (Bahcecioglu & Gjaerum 2003). Aecia also
are not described for P. echeveri Linder 1938 (Linder
1938) on Echeveria, P. exanthematica McOwan 1892
on Crassula (Doidge 1927), P. rydbergii Garrett 1914
on Sedum (Arthur 1934), Puccinia sedi Körn. 1884 on
Sedum (Pantidou 1969) and Uredo tillaeae McAlp.
1906 (McAlpine 1906) on Tillaea.
The rust species Endophyllum sempervivi (Alb. &
Schwein.) de Bary 1863 (Arthur 1934) and E. sempervivi var. aecidioides Maire 1900 (Maire 1900), both
known on species of Sempervivum (Crassulaceae), and
E. sedi (DC.) Lév. 1825 on Sedum spp. (Saccardo 1888),
produce spermogonia and aecidioid telia with onecelled, catenulate teliospores. Although the telia and
teliospores of those species of Endophyllum are similar
to the aecia and aeciospores of A. kalanchoe, the teliospores of those taxa are larger than the aeciospores of
A. kalanchoe and have a thick (3–4 mm), pigmented cell
wall.
848
A nucleotide BLAST analysis (http://www.ncbi.nlm.
nih.gov/BLAST) and preliminary phylogenetic analyses (Aime, data not shown) of the nuclear ribosomal
large subunit (nLSU) DNA sequences place A. kalanchoe in the Pucciniaceae, and suggest that the teleomorph is most likely allied to Puccinia.
ACKNOWLEDGEMENTS
Many thanks are extended to Elizabeth Vavricka (Idaho Department
of Agriculture, Boise) for sending the infected material. We gratefully
acknowledge Christian Feuillet for the Latin description, and Amy
Y. Rossman for many improvements to the text and other useful
comments and suggestions.
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Corresponding Editor: R. W. S. Weber
jose hernadez