Mulberry yellow dwarf(MYD)disease is an quarantine disease and the causal agent is a phytoplasma.Two pairs of published universal primer,P1/P7 and Rm16F2/Rm16R1,based on the 16S-23S rDNA sequence of phytoplasma and to...Mulberry yellow dwarf(MYD)disease is an quarantine disease and the causal agent is a phytoplasma.Two pairs of published universal primer,P1/P7 and Rm16F2/Rm16R1,based on the 16S-23S rDNA sequence of phytoplasma and total DNA extracted from infected mulberry tissues were employed for PCR and nested-PCR detection.The results revealed that a phytoplasma-specific 1 830 bp fragment with a G+C content of 46.01% was sequenced(GenBank accession No.GQ249410).The sequence shared 99.7% and 99.8% identity with aster yellows,the representatiive phytoplasma in 16SrI group,and mulberry dwarf phytoplasma classified into subgroup B in 16SrI group and named as the MYD phytoplasma strain Anhui(MYD-Anh).A phylogenetic tree based on 16S rDNA sequences was constructed and showed that MYD-Anh was clustered into 16SrI group.Identity of 16S rDNA sequence between MYD-Anh and mulberry yellow dwarf phytoplasma strain Zhenjiang(MD-zj) was nearly 100%,and they might belong to the same strain.Nested-PCR was used to detect the pathogenic phytoplasma from the differential tissues of mulberry infected with MYD-Anh.The results showed that a phytoplasma-specific 1.4 kb fragment was amplified with total DNA extracted from bark and vein.Nested-PCR was more sensitive than PCR for detecting MYD phytoplasma.展开更多
文摘Mulberry yellow dwarf(MYD)disease is an quarantine disease and the causal agent is a phytoplasma.Two pairs of published universal primer,P1/P7 and Rm16F2/Rm16R1,based on the 16S-23S rDNA sequence of phytoplasma and total DNA extracted from infected mulberry tissues were employed for PCR and nested-PCR detection.The results revealed that a phytoplasma-specific 1 830 bp fragment with a G+C content of 46.01% was sequenced(GenBank accession No.GQ249410).The sequence shared 99.7% and 99.8% identity with aster yellows,the representatiive phytoplasma in 16SrI group,and mulberry dwarf phytoplasma classified into subgroup B in 16SrI group and named as the MYD phytoplasma strain Anhui(MYD-Anh).A phylogenetic tree based on 16S rDNA sequences was constructed and showed that MYD-Anh was clustered into 16SrI group.Identity of 16S rDNA sequence between MYD-Anh and mulberry yellow dwarf phytoplasma strain Zhenjiang(MD-zj) was nearly 100%,and they might belong to the same strain.Nested-PCR was used to detect the pathogenic phytoplasma from the differential tissues of mulberry infected with MYD-Anh.The results showed that a phytoplasma-specific 1.4 kb fragment was amplified with total DNA extracted from bark and vein.Nested-PCR was more sensitive than PCR for detecting MYD phytoplasma.
