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The presence of Citrus tristeza virus can change the course of citrus industry in Syria.

The presence of Citrus tristeza virus can change the course of citrus industry in Syria.
Citrus tristeza virus (CTV) is the causal agent of the most important virus disease of citrus. CTV was detected for the first time in the Syrian citrus-growing areas of Lattakia and Tartous by Direct Tissue Print Immunobinding Assay (DTBIA) in 2006. About 2600 samples from commercial orchards and nurseries were tested, showing an infection rate of 3.5%. Sweet oranges were the most infected in both types of stands. In particular, the virus was detected in 16 Navel orange trees, used as budwood sources from Lattakia. Most of the infected trees were apparently symptomless. To determine the genetic diversity and CTV strains present in the country, infected samples were examined by single strand conformation polymorphism (SSCP) of the major coat protein (CP), multiple molecular markers analysis (MMM), and sequence analysis of the CP gene. SSCP analysis of CP yielded two distinct simple patterns and CP sequence analysis showed that both SSCP profiles belonged to viral isolates genetically related to the severe VT strain. This finding was also confirmed by MMM analysis. In fact, all infected samples reacted only with VT-specific markers (primer VTPOL, VT5’, VTK17). None of the other known CTV genotypes were detected in the survey. Since the CTVsensitive sour orange rootstock is widely used in the Syrian citrus industry, the discovery that only severe VT-like strains are spreading is especially worrying, and calls for the urgent enforcement of an effective national CTV management plan. Preventive measures such as monitoring and eradication of the pathogen as well as the control of vector populations must be prioritized as a first step towards the implementation of an efficient certification programme of citrus propagating material.
Publié en
Arab Journal of Plant Protection. Vol 27, Special Issue, V502.
24/07/13 - Introduit par: Raied Abou kubaa
Quantitative & qualitative enhancement of crop products
Thème principal: Quantitative & qualitative enhancement of crop products
Sous-catégorie Pre-harvesting