During January 2010, severe stunting symptoms were observed in clonally propagated oil palm (Elaeis guineensis Jacq.) in West Godavari district, Andhra Pradesh, India. Leaf samples of symptomatic oil palms were collected, and the presence of phytoplasma was confirmed by nested polymerase chain reaction (PCR) using universal phytoplasma-specific primer pairs P1 ⁄ P7 followed by R16F2n ⁄ R16R2 for amplification of the 16S rRNA gene and semi-nested PCR using universal phytoplasma-specific primer pairs SecAfor1 ⁄ SecArev3 followed by SecAfor2 ⁄ SecArev3 for amplification of a part of the secA gene. Sequencing and BLAST analysis of the 1.25 kb and 480 bp of 16S rDNA and secA gene fragments indicated that the phytoplasma associated with oil palm stunting (OPS) disease was identical to 16SrI aster yellows group phytoplasma. Further characterization of the phytoplasma by in silico restriction enzyme digestion of 16S rDNA and virtual gel plotting of sequenced 16S rDNA of 1.25 kb using iPhyClassifier online tool indicated that OPS phytoplasma is a member of 16SrI-B subgroup and is a ÔCandidatus Phytoplasma asterisÕ-related strain. Phylogenetic analysis of 16S rDNA and secA of OPS phytoplasma also grouped it with 16SrI-B. This is the first report of association of phytoplasma of the 16SrI-B subgroup phytoplasma with oil palm in the world.
Samples from toria plants (Brassica rapa L. subsp. dichotoma (Roxb.)) exhibiting phyllody, virescence, witches broom, extensive malformation of floral parts, formation of bladder like siliquae and flower sterility were collected from four different locations in India. Sequencing and phylogenetic analysis of the 16S rRNA, a part of 23S rRNA, partial sec A genes, rp gene and 16S-23S intergenic spacer region indicated that the phytoplasmas associated with toria phyllody (TP) symptoms were identical and belonged to 16SrIX phytoplasma Pigeon pea witches'-broom (PPWB) group. The iPhyClassifier generated virtual RFLP pattern of 1.25 kb 16S rDNA sequences indicated that TP phytoplasma belongs to 16SrIX-C phytoplasma subgroup. Complete 23S rRNA gene of TP phytoplasma had 2,787 nucleotides and is the first sequence of 16SrIX phytoplasma group. Restriction digestion of 16S rDNA and 23S rDNA PCR products has also shown that TP phytoplasmas from all the four locations in India were identical. Toria is a previously unreported host for a phytoplasma in16SrIX-C subgroup.
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