First Report of “CandidatusPhytoplasma Asteris”-Related Strains Infecting Chinaberry Trees with Leaf Yellowing Symptoms in Vietnam
During September 2003, leaves of two mature Chinaberry (Melia azedarach) trees in Vietnam displayed distinctive interveinal yellowing. Eight collected samples of yellowed leaves were extracted and assayed for phytoplasma DNA using PCR. After P1/P7-primed products were reamplified by PCR with nested phytoplasma universal 16S rRNA primer pair R16mF2/R16mR1, a 1.4-kb product of predicted size was obtained from eight samples and eastern Aster yellows positive control, while no product was obtained from DNA of seed-grown healthy periwinkle included as a negative control. Chinaberry phytoplasmas were definitively identified as group 16SrI strains after reevaluation of samples by a PCR incorporating ribosomal protein (rp) gene primer pair rpF1/rpR1 and reamplification of resulting products with nested 16SrI group-specific primer pair rp(I)F1A/rp(I)R1A. Sequence comparison and phylogenetic analysis of Chinaberry yellows phytoplasma (CbY-V) 16S rDNA (GenBank Accession No. AY863003) determined this strain to be most closely related (99.65%) to Epilobium phyllody phytoplasma, a 16SrI-B subgroup strain. However, based on analysis of rp gene sequences (GenBank Accession No. DQ321823), strain CbY-V was judged most similar (99.59%) to cabbage proliferation, a well-characterized 16SrI-B subgroup, rpI-B subgroup phytoplasma. This is thought to be the first record of phytoplasma infection of Chinaberry in Vietnam.
Harrison, N.A.; Boa, E. First Report of &#8220;CandidatusPhytoplasma Asteris&#8221;-Related Strains Infecting Chinaberry Trees with Leaf Yellowing Symptoms in Vietnam. Plant Disease (2006) 90 (4) 527-527. [DOI: 10.1094/PD-90-0527A]