Poster for CIAT 2009 Knowledge Sharing Week

1. Viral Diseases of Tomato (Solanum lycopersicum) and their
Management in Colombia.
Francisco J. Morales1, Pablo J. Tamayo2, Mauricio Castaño1, Cristian Olaya1, Ana Karine Martínez1,
Castañ Martí
Ana C. Velasco1.
1 Virology Research Unit, International Center for Tropical Agriculture (CIAT), Palmira, Valle, y 2Corporación Colombiana de Investigación Agropecuaria
Agriculture Corporació Investigació
(CORPOICA), Rionegro, Antioquia, Colombia. Contact: f.morales@cgiar.org
Tomato is one of the most important high-value crops grown in Colombia, where it Cucumber mosaic cucumovirus (CMV):
represents 15% of all vegetables produced for internal consumption and export (9.6% of the Cucumoviruses of tomato have been detected in the departments of Caldas and Risaralda.
fresh vegetables exported). Unfortunately, only 15.000 Ha are planted to tomatoes in CMV has an extensive host range. Infected plants become yellow, bushy and are often
Colombia with a relatively modest yield average (26 TM/Ha), which is less than a third of the stunted. Leaves may be extremely distorted and malformed. Leaflets are often very
yield average in the United States, Chile or Spain. Among the various factors that affect narrowed, producing the symptom known as quot;shoestringquot;. Severely affected plants
tomato productivity in Colombia, different plant viruses are known to cause significant yield produce little fruit. CMV is transmitted in a non-persistent manner by several aphid species.
losses in Colombia. The Virology Research Unit (VRU) of CIAT, in cooperation with the The virus is apparently not seed transmitted in tomato. The management of this virus is
National Agricultural Research Corporation (CORPOICA), have been monitoring, detecting extremely difficult by means other that genetic resistance.
and identifying the plant viruses that infect tomato in Colombia.
Techniques used for virus detection:
•Electron microscopy: Negative staining and inmunosorbent electron microscopy.
•Serology: ELISA with specific monoclonal and polyclonal antibodies for tomato viruses.
•Molecular biology: ds RNA extraction, PCR and RT-PCR; cloning and sequencing.
Figure 4. CMV symptoms and isometric particles.
Viruses identified in Colombia to date:
Pepper yellow mosaic virus (PepYMV):
Tobacco mosaic and/or Tomato mosaic viruses (TMV/ToMV): This potyvirus has been detected in the departments of Cundinamarca, Santander, Valle
One or both of these highly contagious tobamoviruses have been detected in the del Cauca, Antioquia, Caldas and Cauca. Symptoms consist of intense yellow mosaic,
departments of Cesar, Norte de Santander, Risaralda, Antioquia, Valle del Cauca and weakening of the infected plants and yield reduction. This virus is transmitted by aphids in
Nariño with an incidence of 30% to 80%. However, these viruses are usually present a non-persistent manner, hence, the difficulty in controlling potyviruses, other than through
wherever tobacco and/or tomato are grown around the world. Infected plants can present the use of resistant genotypes.
mosaic or mottling on the leaves, with foliar malformations and downward curling; and plant
dwarfing. Infected tomato fruits can be small, and may show brown streaks and irregular
ripening. Tobamoviruses can be seedborne in tomato and are readily transmitted
mechanically by human activities, but these viruses do not have a known biological vector,
other than people. Care must be taken not to contaminate tomato seedlings in the nursery
stage, through proper asepsy. Smokers should not be allowed to manipulate the seedlings
in the nursery or plants in the field. The use of tobamovirus-resistant tomato varieties or
hybrids is recommended.
Figure 5. PepYMV symptoms and flexuous rod particles.
Potato yellow vein virus (PYVV):
This crinivirus has been observed in the department of Cundinamarca. Symptoms include
interveinal yellowing and severe chlorosis. Criniviruses are transmitted by the greenhouse
whitefly Trialeurodes vaporariorum Westwood. Currently, the most effective method to
control criniviruses is through the use of selective and systemic insecticides at planting time,
and up until fruit formation.
Figure 1. Leafs and fruit exhibid TMV/ToMV symptoms, and rigid rod particles.
Tomato yellow mosaic virus (ToYMV):
This begomovirus has been detected in the departments of Cundinamarca, Santander,
Valle del Cauca, Tolima and Caldas, with incidences ranging from 50-70%. The virus
usually causes yellowing, mosaic, leaf distortion, leaf curling and stunting. ToYMV is
transmitted by the whitefly Bemisia tabaci. Tomato seedlings should be produced under
protected conditions (e.g. screen- or glass-houses) and with a seed treatment before
transplanting. Further use of systemic insecticides or physical protection may be necessary
in regions with a high whitefly and virus incidence. The planting of virus-resistant varieties
or hybrids should be the best virus control strategy, but these varieties are yet to be
developed. Figure 6. PYVV symptoms and flexuous particles.
Tobacco ringspot virus (TRSV) and Impatiens necrotic spot virus (INSV) were reported
before by other researchers in Colombia. (Sánchez de Luque, 1989; Figueroa et al, 1994;
1995).
A new virus was also recently detected in the department of Antioquia, and is currently
under investigation. Virions are isometric particles c. 30 nm in diameter, and infected
tomato plants show mosaic, fruit and leaf malformation. A cytopathological study of
infected leaf cells, revealed the presence of isometric virus-like particles contained in
cytoplasmic vesicles, and chloroplasts with vesicles and vacuoles of different sizes. ds-
RNA extractions of infected plant showed the presence of three bands of approximately
6.4, 3.5 and 0.8 kb in size.
Figure 2. ToYMV symptoms in leaf, whitefly Bemisia tabaci, geminate
particles and physical protection
Tomato spotted wilt virus (TSWV): M L L F F
6392 bp
Detected in the departments of Antioquia, Cundinamarca and Boyacá. Characteristic 3461 bp
symptoms are ringspots (yellow or brown rings) or other line patterns, black or dark brown
streaks on petioles or stems, necrotic leaf spots, or tip dieback. Young leaves may show
small dark-brown spots and eventually die. Dark brown streaks may also appear on stems
and leaf petioles, together with systemic necrosis and greatly stunted growth. Tomato fruits
813
on severely infected plants usually display rugose skin, necrotic spots, deformation, bp
discoloration and green, yellow or red rings with raised centers. TSWV is transmitted in a
persistent manner by various species of thrips. The use of resistant varieties, destruction of
affected plants, and thrip control at the source of their population, are highly recommended.
Figure 7. New virus symptoms in leaf and fruit, isometric particles, bands of ds RNA
extraction and vesicle containing virions.
References
Figueroa, A., Márquez, l., Vallejo, F.A., Huertas, C.A. & B. Pineda. 1994. La
“Chamusquina” del tomate, enfermedad ocasionada por un tospovirus en aují y Regaderos
(Cerrito, Valle). ASCOLFI Informa 20 (6): 81-83
Morales, F.J., Martínez, A.K. & A.C. Velasco. 2002. Nuevos brotes de begomovirus en
Colombia. Fitopatología Colombiana 26(2): 75-79
Morales, F.J., Martínez, A.K., Olaya, C. & A.C. Velasco. 2004. Detección en tomate
(Lycopersicon esculentum Mill.) del virus del amarillamiento de las nervaduras de la papa
(Potato yellow vein virus) en Cundinamarca, Colombia. Fitopatología Colombiana 28(1):
40-44
Figure 3. TSWV symptoms in leaf and fruit, roughly spherical particles detected by
ISEM. Sánchez de Luque, C. 1989. El virus de la mancha anular del tabaco en cultivos de
tomate en Risaralda. ASCOLFI Informa 15(4): 35-37