First Report of Barley as Host of a Phytoplasma Belonging to Group 16SrI, Subgroup B, and Ribosomal Protein Subgroup rpI-B in Lithuania

Abstract

Numerous diseased plants of barley (Hordeum vulgaris L.) exhibiting twisted, abnormally thin and yellowed awns, reduced spikelets, and general stunting and yellowing were observed in fields in the Vilnius and Kaisiadorys regions of Lithuania. The possible association of a phyto-plasma with the disease, termed barley deformation (BaDef), was assessed using polymerase chain reaction (PCR). Three phytoplasma universal primer pairs (P1/P7, R16F2n/R16R2, and rpF1/rpR1) (1,2,4) were employed to amplify ribosomal (r) RNA gene (rDNA) and ribosomal protein (rp) gene sequences. Template DNA extractions and PCR (direct and nested) were conducted as previously described (4). Although DNA was amplified in PCRs containing template extracted from diseased plants, no amplification was observed in PCRs containing DNA from symptomless plants sampled from the same fields. The BaDef phytoplasma was identified and classified according to Lee et al. (4) through restriction fragment length polymorphism (RFLP) analysis of 1.2-kbp 16S rDNA amplified in the PCR primed by primer pair R16F2n/R16R2 and analysis of the 1.2-kbp rp gene sequences amplified in PCR primed by primer pair rpF1/rpR1. On the basis of collective RFLP patterns of amplified 16S rDNA and rp gene sequences, the BaDef phytoplasma was classified as a member of group 16SrI (group I, aster yellows phytoplasma group), subgroup B (16SrI-B), and rp subgroup rpI-B. Ribosomal protein subgroup B was distinguished from other rp subgroups on the basis of the presence of a recognition site for HpaII. The 1.8-kbp rDNA product of PCR primed by P1/P7 and the 1.2-kbp rpF1/rpR1 PCR product were cloned and sequenced, and the sequences were deposited in GenBank under Accession No. AY734453 for the BaDef 16S rDNA and Accession No. AY735448 for the BaDef rp gene sequence. Previously, only oat proliferation (OatP) phytoplasma, a member of subgroup 16SrI-A, had been characterized in a cereal crop (Avena sativa L.) in Europe (3); BaDef is another phytoplasmal disease threatening cereal crops in the region. References: (1) S. Deng and D. Hiruki. J. Microbiol. Methods 14:53, 1991. (2) D. E. Gundersen and I. M. Lee. Phytopathol. Mediterr. 35:144, 1996. (3) R. Jomantiene et al. Plant Dis. 86:443, 2002. (4) I. M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998.

'Candidatus Phytoplasma fragariae', a novel phytoplasma taxon discovered in yellows diseased strawberry, Fragariaxananassa

“…Fifteen phytoplasma groups (16Sr groups) and more than 40 subgroups have been delineated on the basis of results from RFLP analysis of 16S rRNA gene sequences (Lee et al, 1998;Marcone et al, 2000;Davis et al, 2001;Jomantiene et al, 2002a). Thus far, three 16Sr groups (16SrI, 16SrIII and 16SrV) and eleven subgroups have been reported in Lithuania (Jomantiene et al, , 2002aStaniulis et al, 2000;Valiunas et al, 2000Valiunas et al, , 2001aValiunas et al, , b, 2004Urbanaviciene et al, 2005). Based on 16S rRNA gene sequences, 20 'Candidatus Phytoplasma' species have been described (IRPCM, 2004;Schneider et al, 2005).…”