Molecular detection and characterization of 16SrI phytoplasma associated with rice orange leaf symptom in Vietnam

Rice plants showing orange leaf disease symptoms were observed in Southern Vietnam. A nested polymerase chain reaction assay using phytoplasma-universal primer pairs P1/P7 and R16F2n/R16R2 amplified products of approximately 1.2 kb only from symptomatic rice plants. Sequence analysis of 16Sr DNA amplicons showed that the phytoplasma strain VNTG-4 shared 100% sequence homology with phytoplasma strains from rice in Thailand, members of the 16SrI group. This is the first detection and identification of a phytoplasma associated with the orange leaf disease in Vietnam.