Abstract

FIGUEROA, Julia et al. Confirmation of the presence of citrus viroids in citrus orchards in Northwestern Argentina. Rev. ind. agric. Tucumán [online]. 2010, vol.87, n.1, pp.45-48. ISSN 1851-3018.

Citrus viroids cause two well known diseases: exocortis and cachexia. In the citrus area of Northwestern Argentina, the presence of viroids was reported in the 1960's and diagnosis was based only on visual symptoms on susceptible rootstocks. From 2004 onwards, budwood samples from citrus trees showing viroid symptoms have been collected in Tucumán, Salta and Jujuy provinces. Biological indexing has been performed using Etrog citron Arizona 861-S1 grafted on rough lemon seedlings as the indicator plant. Since 2006, molecular diagnosis has also been performed using sequential polyacrylamide gel electrophoresis (sPAGE). The presence of viroids has been confirmed for the first time in northwestern region, using both techniques. Symptoms obtained in inoculated Etrog citron vary from mild to very severe. sPAGE utilization showed that most infections consisted of mixtures of two or more viroids. All viroid isolates are kept in the virus bank at the Citrus Sanitation Center of EEAOC in Tucumán. Currently, 22 isolates from Northwestern Argentina are stored and further characterization of these viroids will be done using PCR.

Keywords : Exocortis; Cachexia; Indexing.

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