An in vitro bioassay for evaluating the virulence of Pseudomonas savastonoi pv savastanoi isolates on olive

Authors: SALMAN, MAZEN - Palestine Technical University- Kadoorie; McClean, Ali; Kluepfel, Daniel

Submitted to: Australasian Plant Disease Notes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/4/2022
Publication Date: 1/7/2022
Citation: Salman, M., McClean, A.E., Kluepfel, D.A. 2022. An in vitro bioassay for evaluating the virulence of Pseudomonas savastonoi pv savastanoi isolates on olive. Australasian Plant Disease Notes. 17:1. https://doi.org/10.1007/s13314-022-00448-0.
DOI: https://doi.org/10.1007/s13314-022-00448-0

Interpretive Summary:

Technical Abstract: Pseudomonas savastanoi pv. savastanoi is the causal agent of olive knot disease that afflicts olive trees globally. Understanding the mechanism of disease development by Psav requires reliable isolation and purification methods that facilitate rapid recovery of Psav from the knots as well as a sensitive and reproducible in vitro pathogenicity bioassay. We developed an enhanced selective medium for the isolation and purification of Psav from plant tissue which consisted of KB medium amended with Vancomycin, Cephalexin and Cycloheximide at 150, 50 and 50 µg ml-1, respectively. Eighty Psav isolates were obtained from 15 olive genotypes. A virulent Psav strain was used to develop a quick and non-destructive in vitro pathogenicity bioassay using detached leaf segments of the olive cultivar “Manzanillo”. Symptom development was obvious under 20X magnification after 10 days of incubation at 25°C. This bioassay will facilitate the rapid screening of the olive germplasm collection for resistance to OK.