Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 6/15/2011
Publication Date: 8/15/2011
Citation: Sudarshana, M.R., Gonzalez, A., Dave, A.M., Uyemoto, J.K. 2011. A quantitative PCR assay for the detection of phytoplasmas causing almond brownline, peach yellow leafroll, and pear decline diseases in California. Phytopathology. 101:S172.
Technical Abstract: Phytoplasmas cause several important diseases in California’s almond and fruit tree orchards. A phytoplasma associated with almond brown line (ABL) disease, peach yellow leafroll phytoplasma (PYLR-P) and pear decline phytoplasma (PD-P) are genetically related based on homology in the 16S-23S rDNA spacer region. In an attempt to detect these three phytoplasmas, a primer pair was designed to amplify a 530-bp product from the 16S-23S rDNA spacer region. Using this primer pair and SYBR Green, a quantitative PCR (qPCR) assay was developed to facilitate detection and analysis from multiple samples. A detection limit of 100 copies was achieved in assays using nucleic acid extracts from almond leaves spiked with cloned target DNA from PYLR-P. The qPCR assay detected PYLR-P in almond and peach trees, PD-phytoplasma in pear trees, but not a genetically different X-disease phytoplasma in cherry trees. This new assay was also able to detect PYLR-phytoplasma in dormant peach buds from infected trees and is expected to aid in the detection and amplification of ABL-P, PYLR-P and PD-P in almond, peach and pear trees, respectively.