LIBRO-CONGRESO-CITRUS

detected in the main trunk and roots. The new assay is a valuable tool to screen for resistance and a major
improvement for CPsV detection in sanitation, quarantine and certification programs.
S14P23
Improvement in diagnosis for Citrus Psorosis in Argentina by qRT-PCR
de Francesco A. 1 , Reyes C.A. 1 , Costa N. 2 , and Garcia M.L. 1
1 Instituto de Biotecnología y Biología Molecular (IBBM), La Plata, Buenos Aires, Argentina; 2 Estación Experimental Agropecuaria
Concordia (INTA EEA Concordia), Entre Rios, Argentina. agustinadefrancesco@hotmail.com
Citrus is one of the most important crops in Argentina, a leading export country of oranges and lemons.
Several diseases affect citrus in Argentina, among them Psorosis is still a serious and widespread viral disease,
making trees less productive and causing economic losses. In the field, symptoms are observed mainly in
sweet orange, showing bark scaling restricted to the main trunk and limbs, and chlorotic flecks and spots
in young leaves. Citrus psorosis virus (CPsV), the casual agent of the disease is the type member of genus
Ophiovirus, family Ophioviridae. Virus particles have filamentous circular morphology, and its genome has
three negative single-stranded RNAs encapsidated with a coat protein. CPsV can be detected by TAS-ELISA
using polyclonal and monoclonal antibodies and by RT-PCR with specific primers. These procedures are
faster and more reliable than biological indexing. Real-time RT-PCR (qRT-PCR) using Taqman probes has been
applied successfully for detection of Mexican and European CPsV isolates. In this work, we applied a new qRT-
PCR using SYBR Green and specific primers designed in a region of the coat protein gene that is conserved in
Argentinian isolates in order to improve disease control in our country. We compared our results of qRT-PCR
with TAS-ELISA and RT-PCR applied in field samples and will discuss reliability of these methods.
S14P24
Cloning and sequence analysis of the large coat protein of Satsuma dwarf virus Fengjie isolate
Sun X.C. 1 , Qing L. 1 , Yang F.Y. 2 , and Zhou C.Y. 2
1 Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing, China; and
2 National Center of Citrus Engineering and Technology Research, Citrus Research Institute of Chinese Academy of Agricultural
Sciences, Chongqing, China. xianchaosun@gmail.com
Satsuma dwarf virus (SDV) mainly infects satsuma mandarins, causing serious Satsuma Dwarf disease. In
China, Satsuma Dwarf was found in Fengjie of Chongqing, Wu city of Jiangsu province and Huangyan of
Zhejiang province since satsuma mandarins were introduced from Japan in the 1980s. However, it is unclear
whether the virus in China and the S-58 isolate reported from Japan are the same strain or whether SDV has
evolved and become adapted to the new environment and hosts. To answer this question, the large coat
protein (CPL) gene of SDV isolated from Fengjie (SDV FJ) was amplified by RT-PCR and cloned into vector
pGEM-T for sequencing. Sequence analysis showed that the SDV-FJ CPL gene had 1329 nt, encoding a protein
of 443 amino acids. Comparison of this sequence with those of other viruses of the genus Sadwavirus showed
high nucleotide and amino acid identity (98.1% and 98.6%) between SDV FJ and SDV S-58 from Japan. The
SDV FJ CPL gene had 25 nucleotide differences with the SDV S-58 CPL, the most frequent being T and C
transitions. Therefore, it is suggested that the SDV FJ and S-58 are the same strain of SDV.
S14P25
Characterization and incidence of Citrus leaf blotch virus (CLBV) in Southern Italy
Guardo M., Sorrentino G., and Caruso A.
CRA - Centro di Ricerca per l’Agrumicoltura e le Colture Mediterranee (CRA-ACM), Italy. guido.sorrentino@entecra.it
Citrus leaf blotch virus (CLBV), the type species of the new genus Citrivirus of the family Flexiviridae, has
been associated with a bud union disorder of Nagami kumquat and calamondin scions grafted on trifoliate
rootstocks. After the first report in Italy in 2007, surveys to monitor CLBV incidence were carried out in
nurseries, private collections and commercial citrus orchards with bud union disorder problems from Sicily
and Calabria using biological indexing and RT-PCR. Each positive sample was analysed by Single-Strand
XII INTERNATIONAL CITRUS CONGRESS 2012 - 247
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