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First report of phytoplasmas affecting organoponic crops in central and eastern Cuba

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Publication date
Type of Publication:
Articles & Journals
Focus Region:
Latin America & the Caribbean
Focus Topic:
Agricultural Value Chains / Agri-Businesses
Arocha, Y.; Pi??ol, B.; Almeida, R.; Acosta, K.; Qui??ones, M.; Zayas, T.; Varela, M.; Marrero, Y.; Boa, E.; Lucas, J.A.

Surveys of organoponics (organic and hydroponic systems) in Matanzas, Las Tunas and Stgo de Cuba provinces revealed the occurrence of phytoplasma diseases with a 20-30% incidence, whose patchy distribution suggested an insect vector role in disease spread. Symptoms were observed in cabbage (Brassica oleracea), beetroot (Beta vulgaris) and cassava (Manihot esculenta), mostly associated with leaf yellowing, small fruits, and stunting. Radish (Raphanus sativus) plants showed leaf yellowing, mosaic, crinkling, and smaller leaves, whereas carrot (Daucus carota) plants exhibited yellowing and purpling of leaf tips, resulting in progressive necrosis with little leaves and shortening of internodes. Thirty-two symptomatic and 12 asymptomatic plants were randomly surveyed for total DNA extraction and indexing in a nested PCR with generic phytoplasma 16S rRNA primers R16mF2/R1 and fU5/rU3. Nested PCR amplicons (~880 bp) were obtained for 26 of the 32 samples from the symptomatic species surveyed, with no amplicons from the asymptomatic plants. PCR products were purified, cloned and sequenced. All samples showed that Sau3AI, HpaII and HaeIII RFLP patterns identical to the 16SrI-C reference control ‘Candidatus Phytoplasma asteris’ [Phytoplasma asteris], except those from radish that were identical to the 16SrII-A reference control ‘Ca. Phytoplasma aurantifolia’ [P. aurantiifolia]. The phytoplasma 16S rRNA sequences scored 99% identity for carrot (GenBank Accession No. EU328254), cabbage (EU328252), beetroot (EU328251), and cassava (EU328256) with those of members of group 16SrI; and for the radish phytoplasma (EU328253) with members of group 16SrII. This is thought to be the first report of both a 16SrI phytoplasma affecting carrot, cabbage, beetroot and cassava, and 16SrII phytoplasma in radish under organoponics in central and eastern Cuba