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Detection and identification of ‘Candidatus Phytoplasma asteris’-related phytoplasma associated with a witches’broom disease of cassava in Cambodia
E. ALVAREZ (1), J. M. Pardo (2), M. J. Truke (2). (1) CIAT, Cali, Colombia; (2) CIAT, Palmira, Colombia

Cassava witches’ broom (CWB) is an important disease of <i>Manihot esculenta </i>Crantz that is widely cultivated across South East Asia. In 2012, cassava farms were affected in Cambodia with significant crop losses up to 50% and reductions in yield and starch content. The disease was observed in Kampong Cham, Kratie and Prey Veng provinces of Cambodia affecting the availability of clean planting material. Understanding the etiology of this disease is critical for managing infection by the pathogen. Restriction fragment length polymorphism analyses of nested PCR-amplified fragments from Cambodian CWB phytoplasma isolates and representative phytoplasmas from other phytoplasma groups using <i>Mse</i>I restriction enzyme indicated that the cassava phytoplasma isolates are related to the aster yellows (16SrI) group. Sequence analyses of partial 16S rRNA fragments showed that Cambodian CWB phyoplasmas have 99% to 100% similarity with ‘<i>Candidatus</i> phytoplasma Asteris’(16SrI) phytoplasma group. To our knowledge, this is the first report of cassava infection with a phytoplasma related to the 16SrI group in Cambodia.

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