First report of 'Candidatus Phytoplasma mali' in oriental lilies and its association with leaf scorch in Poland
Department of Plant Protection, Research Institute of Pomology and Floriculture, 96-100 Skierniewice, Pomologiczna 18, Poland
Accepted: 21 Jun 2007
Leaf scorch or leaf burn, usually considered to be a physiological problem, is the most important disorder of lily plants occurring during production under cover. Symptoms of leaf scorch observed on oriental lily hybrids cv. Siberia in several greenhouses in Poland included leaf malformation and necrosis and flower bud abscission. Similar symptoms in lily cv. Woodriff's Memory were associated with the presence of 'Candidatus Phytoplasma asteris' (Kamińska & Dziekanowska, 2002). This phytoplasma has been reported in several lily cultivars in Poland (Kamińska & Korbin, 2000; Bertaccini et al., 2002).
Nucleic acids were extracted from bulb scales using a DNeasy Plant Mini Kit (Qiagen). In nested PCR the phytoplasma universal primer pair P1/P7 was used, followed by fA/rA, R16F2n/R16R2 or the group-16SrI (R16(I)F1/R16(I)R1) or group-16SrX (fAT/rAS) specific primer pairs. Restriction fragment length polymorphism (RFLP) analysis of R16F2n/R16R2 PCR product was done using the endonucleases MseI, HhaI, RsaI or SspI. The PCR-amplified 16S rRNA gene fragment of lily 'Siberia' phytoplasma was purified and sequenced.
Phytoplasma rDNA fragments were amplified by nested PCR fA/rA, R16F2n/R16R2 and fAT/rAS but not with R16(I)F1/R16(I)R1 primers from three lilies out of more than 75 (five cultivars) tested, all with disease symptoms. No products were amplified from three symptomless lilies or Catharanthus roseus plants. RFLP profiles indicated that lilies 'Siberia' were infected with a phytoplasma belonging to 16SrX-A subgroup ('Ca. Phytoplasma mali'). Analysis of the sequence determined in this study (GenBank acc. no. EF370450) confirmed the results of PCR-RFLP. The isolate showed the highest similarity to the members of 'Ca. Phytoplasma mali'. A BLAST analysis of the sequence from lily 'Siberia' revealed that it was most closely related to the phytoplasmas deposited in GenBank under accession numbers AY598319 and AJ542541.
16SrX-A subgroup phytoplasmas have been reported frequently from woody plants. In Poland, they have been found in ornamental crops including rose (Kamińska & Śliwa, 2004). To our knowledge, this is the first record on the occurrence of 'Ca. Phytoplasma mali' in lily plants.
This research was supported by the State Committee of Scientific Research (KBN), Grant No 2 PO6R 029 29.
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This report was formally published in Plant Pathology
©2007 The Authors