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ARS Home » Southeast Area » Poplarville, Mississippi » Southern Horticultural Research Unit » Research » Research Project #440407

Research Project: Development of qPCR Protocol to Detect the Bacterium Causing Loropetalum Knot from the Phylloplane of Loropetalum Stems

Location: Southern Horticultural Research Unit

Project Number: 6062-21430-004-031-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Aug 1, 2021
End Date: Sep 30, 2025

1. Recover isolates of Pseudomonas amygdali pv. loropetali and other Pseudomonas species, particularly P. amygdali and P. syringae species, present in the stem phylloplane of Loropetalum chinense. 2. Obtain whole genome sequences of several Pseudomonas amygdali pv. loropetali isolates. Identify genetic regions suitable for selection of functional molecular primer and probe candidates. 3. Design and test the specificity and sensitivity capabilities of primers and probes in detection of Pseudomonas amygdali pv. loropetali in the phylloplane of Loropetalum stems.

Pseudomonas amygdali pv. loropetali and other Pseudomonads will be recovered from container grown Loropetalum from nurseries in Alabama, Louisiana and Mississippi and the isolates grown in culture for development of molecular probes. The whole genome of the pathotype strain PDC13-208 (Harmon et al. 2018) of P. amygdali pv. loropetali will be sequenced and bioinformatic analyses conducted to identify unique regions for primer and probe designs. Quantitative PCR primers and probe will be designed with specificity to P. amygdali pv. loropetali based on genome-wide sequence analyses. PCR protocol will be optimized using the related bacteria as described by Wang et al. (2019). The specificity and sensitivity of probes will be tested on naturally infested Loropetalum to evaluate their functionality in performing spatial distribution studies of Pseudomonas amygdali pv. loropetali present on infected nursery stock of Loropetalum.