Study on the Etiology and Insect Vectors of Pear Decline Disease in Taiwan
Date Issued
2007
Date
2007
Author(s)
Liu, Hsiu-Lin
DOI
zh-TW
Abstract
Pear decline (PD) is an important phytoplasmal disease that occurs mainly in Europe and North America. In 1994, pear trees exhibiting typical symptoms of PD disease were observed in orchards of central Taiwan. The sequences of 16S rDNA and 16S-23S rDNA intergenic spacer region of the causative agent of pear decline in Taiwan (PDTW) were amplified with polymerase chain reaction (PCR) using a DNA template prepared from the diseased leaves. Sequence analysis of 16S rDNA revealed that the causative agent of PDTW, group 16SrX-PDTW phytoplasma (PDTW phytoplasma), was closely related to the phytoplasmas of the apple proliferation group (group 16SrX) that cause diseases in stone fruits, pear and apple. Consistent with the result of 16S rDNA sequence analysis, sequence analysis of the 16S-23S rDNA intergenic spacer region and putative restriction site analyses of 16S rDNA and 16S-23S rDNA intergenic spacer region sequences provided the further support for the view that the PDTW phytoplasma causing PDTW may be a new subgroup of the apple proliferation group. According to the rDNA sequence of PDTW phytoplasma, various polymerase chain reaction (PCR) primers and PCR-based strategies including specific booster PCR, multiplex PCR, nested PCR and PCR-RFLP were developed and applied in this study for the detection of the causative agent in pear trees and insect vectors. The study of the seasonal variation in the detection of the PDTW phytoplasma was conducted in four pear orchards in Dungshr and Heping. Samples collected from 7-20 infected trees were detected by booster PCR monthly in three consecutive years from 2002 to 2004. Unless there is no leaf sample can be collected from the pear trees in the winter, the PDTW phytoplasma in the pear trees can be detected readily. And the maximum detection rates of PDTW phytoplasma were obtained in the summer. Based on the sequence analyses of the PCR-amplified fragments, two species of pear psyllas, Cacopsylla qianli and Cacopsylla chinensis, were found to carry PDTW phytoplasma.
Subjects
媒介昆蟲
物菌質體
聚合酵素連鎖反應
核醣體RNA基因
insect vector
pear decline-Taiwan (PDTW)
phytoplasma
polymerase chain reaction
ribosomal RNA gene
Type
other
File(s)![Thumbnail Image]()
Loading...
Name
ntu-96-D90633004-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):5121d13089e8cb4f9034fdba06f86c70