Phytoplasmas of Two Different 16S rDNA Groups are Associated with Pear Decline in Taiwan
| Autor: | Shu-Ling Liu, 劉淑玲 |
|---|---|
| Rok vydání: | 2007 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 95 PCR-based detection strategies were applied in the etiology and vectorship studies of pear decline in Taiwan (PDTW). The 16S rDNA sequences were amplified from the total DNAs prepared from PDTW-affected pear trees and pear psylla Cacopsylla chinensis (Yang and Li) with PCR. Based on the sequence analyses, phytoplasmas of two different 16S rDNA groups, 16SrII and 16SrX, were revealed to be associated with PDTW-affected pear trees and carried by C. chinensis (Yang and Li). For detection purposes, specific primers IIPf1/ IIPr1 along with IIPf2/ IIPr1 for group 16SrII-PDTW phytoplasma, PDTWII phytoplasma, and fPD2/ rPDs1 along with APf3/ rPDs1 for group 16SrX-PDTW phytoplasma, PDTW phytoplasma, had been developed and applied in semi-nested PCR. The 16S rDNA sequences of PDTW and PDTWII phytoplasmas amplified from diseased pear tree and those amplified from C. chinensis were identical. Transmission trials of phytoplasmas associated with PDTW to healthy pear plants were carried out with C. chinensis. One of the 17 tested plants was affected with both PDTW and PDTWII phytoplasmas and ten of the 17 tested plants were affected with PDTWII phytoplasma. In grafting tests, PDTW and PDTWII phytoplasmas were transmitted from the same diseased pear to periwinkle plants (Catharanthus roseus (L.) G. Don). Phytoplasma bodies were examined in the sieve tube elements and phloem parenchyma cells of the diseased plants and in cells of intestine wall of C. chinensis and C. qianli by using transmission electron microscopy. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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