Cactus virus X
Biologische Bundesanstalt für Land- und Forstwirtschaft, Braunschweig, Germany
- Described by
- Cactus virus 1 (Rev. appl. Mycol. 38: 585)
- Kakteen-Virus (Rev. appl. Mycol. 38: 192)
An RNA-containing virus with elongated particles, normal length c.
520 nm. Transmissible by inoculation of sap but no natural vector known. Reported
from Europe and USA in cultivated cacti.
Infected cacti probably show no macroscopic symptoms; those symptoms which are
occasionally observed in cacti may be caused by other viruses.
Reported from Europe and USA in cultivated cacti; in USA also in wild cacti (M.
Chessin, personal communication).
Host Range and Symptomatology
Occurs in many cultivated cacti without causing
(Milicic & Udjbinac, 1961
Transmissible by sap inoculation and
grafting. Some species in the Amaranthaceae, Chenopodiaceae and Caryophyllaceae can be
infected experimentally. Infections of species in the Caryophyllaceae are latent. After
inoculation with sap from cacti, symptoms in diagnostic test plants usually require several
weeks to develop; after inoculation with sap from test plants, however, they appear within
a few days
(Plese & Milicic, 1966
- Chenopodium quinoa. The only species consistently infected systemically. Primary
lesions necrotic or chlorotic. Systemic mottle with necrotic and chlorotic spots
Tip leaves usually without systemic symptoms.
- Chenopodium amaranticolor. Necrotic or chlorotic primary lesions. Not systemic.
- Amaranthus caudatus. Necrotic or chlorotic local lesions. Systemic infection
frequent with necrotic spots and sometimes brown veinal necrosis in tip leaves; upper
leaves may be infected without showing symptoms.
- Gomphrena globosa. Necrotic primary lesions with red margins
- Chenopodium quinoa is a useful plant for maintaining cultures and as a source
of virus for purification. The virus reaches high concentrations in systemically infected
- Gomphrena globosa
is a useful local lesion host, though Amaranthus
caudatus and Chenopodium amaranticolor are better for some strains of the virus.
- Chenopodium quinoa is useful for whole plant assay.
Isolates can be differentiated on the basis of their tendency to form either necrotic
or chlorotic local lesions in most plants or a mixture of both types. Three strains have
been clearly differentiated by serology; two of these strains also differ symptomatologically.
Transmission by Vectors
Transmission through Seed
None with cacti
Transmission by Dodder
The virus is strongly immunogenic. The slide precipitin test or the tube test give
good results; the precipitates are flocculent (flagellar). The agar gel-diffusion test
with virus fragments is less sensitive
Some strains are closely related serologically, others distantly
(Milicic et al., 1966
A very distant serological relationship exists to the
following viruses which have particles of the same or similar normal lengths:
white clover mosaic
clover yellow mosaic
potato virus X group
(Brandes & Bercks, 1963
Stability in Sap
In sap from Chenopodium quinoa,
the thermal inactivation point (10 min) is
about 82°C, dilution end-point 10-5
, and infectivity is retained at room
temperature for more than 6 weeks; in dried leaves infectivity is retained for more than
(Plese & Milicic, 1966
The following method gives good virus preparations: add ascorbic acid (to 0.2%) and
sodium sulphite (to 0.2%) to sap from infected Chenopodium quinoa,
adjust pH value
of the sap to 6.5, 7.0 or 8.0 according to the strain used
(Koenig & Bercks, 1968
shake with an equal volume of ether, centrifuge at low speed and discard ether phase.
Shake aqueous phase for 5 min with an equal volume of carbon tetrachloride, centrifuge
at low speed and discard carbon tetrachloride phase, add n
-butanol (to 8% (v/v))
to the aqueous phase and store the mixture at 4°C for 16 h. Repeat treatment with
carbon tetrachloride. Sediment and clarify by two cycles of high and low speed
Use 0.05 M sodium citrate at pH 7.5 for resuspension.
Prolonged contact with crude sap results in degradation of protein subunits
(Koenig et al., 1970
Properties of Particles
Particles are flexuous filaments
normal length c.
520 nm, diameter
(Brandes & Bercks, 1963
M. Wt 2.1 x 106
Protein: Subunits in rapidly purified preparations have a M. Wt of c.
2.0 x 104 but, after prolonged contact with crude sap, values of c. 1.7
x 104 have been found
(Koenig et al., 1970;
Relations with Cells and Tissues
Many inclusion bodies are found in the epidermis of cacti as well as in the epidermis
and sometimes also in the mesophyll of leaves from other host plants. Usually they are
In addition ring-, bow- and thread-shaped structures are formed.
all these structures develop from X-bodies which are formed
early in infection.
- Amelunxen, Protoplasma 49: 140, 1958.
- Brandes & Bercks, Phytopath. Z. 46: 291, 1963.
- Brandes & Bercks, Adv. Virus Res. 11: 1, 1965.
- Koenig, Phytopath. Z. 65: 379, 1969.
- Koenig, J. gen. Virol. 10: 111, 1971.
- Koenig & Bercks, Phytopath. Z. 61: 382, 1968.
- Koenig, Stegemann, Francksen & Paul, Biochim. biophys. Acta 207: 184, 1970.
- Milicic, Acta bot. croat. 18-19: 37, 1960.
- Milicic, Plese, Bercks, Brandes, Casper & Chessin, Phytopath. Z. 55: 211, 1966.
- Milicic & Udjbinac, Protoplasma 53: 584, 1961.
- Plese & Milicic, Phytopath. Z. 55: 197, 1966.
- Wetter, Arch. Mikrobiol. 37: 278, 1960.
Spindle-shaped inclusions in Amaranthus hybridus (x 600).
(Courtesy of D. Milicic, Zagreb.)
Upper leaf of Chenopodium quinoa, systemically infected.
Lower leaf of Chenopodium quinoa, systemically infected.
Local lesions in Gomphrena globosa.
Shadowcast virus particles from a purified preparation. Bar represents