Comparative Identification Of Tow Phytoplasma Strains Associated With Chinaberry Tree Witches'-broom

Using universal primers (R16mF2/Rl and R16F2/R2) for 16S rRNA and primers (rpF1/rpR1) for ribosomal protein gene to detect phytoplasmas associated with of chinaberry tree witches'-broom from Yunnan and Guizhou Province by polymerase chain reaction. This indicated they were phytoplasma diseases and the phytoplasma strains were designed as CWB-YN and CWB-GZh, repectively.The amplified fragments of 16S rRNA gene and ribosomal protein gene of CWB-YN and CWB-GZh were cloned and sequenced,repectively. The results showed that the nucleotide sequences of 16S rRNA genes and ribosomal protein gene were comprised of 1248 base pairs and 1242 base pairs, respectively. Comparing the nucleotide sequences of 16S rRNA gene and ribosomal protein gene, we could find that these two strains have the highest homology of 99.4% and 99.8%, respectively. The nucleotide sequences of 16S rRNA gene for the CWB-YN strain shared higher homology (98.5%,98.9% and 98.0%) with phytoplasma strains in Tomato big bug (16SrI-A group, Western aster yellow (16SrI-B group) and Clover phyllody (16SrI-C group). But it is obviously under 97.0% with other phytoplasma groups. The CWB-GZh strain shared higher homology (98.7%,99.1% and 98.3%) with phytoplasma strains in Tomato big bug(16SrI-A group ),Western aster yellow (16SrI-B group) and Clover phyllody (16SrI-C group). But it is obviously under 97.0% with other groups. With further comparing the rps3 gene of ribosomal protein gene for the CWB-YN strain,the results show that these strains shared highest homology (98.1% and 100%)with Aster yellows and Periwinkle yellows (rp-B group).The rps3 gene of ribosomal protein gene for the CWB-GZh shared highest homology (98.1% and 100%) with phytoplasma strains in Aster yellows (16SrI-B group) and Periwinkle yellows (16SrI-B group). So the results made it clear that this phytoplasma strain is one of the members of Aster yellows phytoplasma group (16SrI-B group).So the results made it clear that these two phytoplasma strains are one of the members of Aster yellows phytoplasma group (16SrI-B, rp-B group).