First Record of Pseudomonas syringae pv. syringae in Iraq using Conventional and Specific PCR Protocol

Abstract

Bacterial canker and gummosis of stone fruits caused by Pseudomonas syringae pv. syringae Van Hall (Pss) were mostly found on dormant buds, blossoms, twigs and trunks rather than leaves and fruits in Duhok, Northern of Iraq. In this work, 262 symptomatic diseased samples collected from apricot, plum and peach trees (dormant buds, flowers, twigs and trunks) during early spring and late summer 2012. The conventional and Polymerase Chain Reaction (PCR) techniques managed to detect and characterize Pss. PCR protocol described uses specific primers C-Duhok B1 and B2 to identification main virulence factor Syringomycin (syrB) gene for the detection of Pss. Diseased samples were initially screened on 5% Nutrient Agar Sucrose (NAS) and 5% Nutrient Broth Sucrose (NBS), selective media of Pseudomonas Agar Base (PAB). Therefore, 139 samples were considered P. syringae. Subsequently, confirmations of 62 isolates from 139 were considered to be of P. syringae on Cetrimide Agar (CA). These isolates found to be gram negative bacilli, short rods and non spore-form and characterized by negative oxidase and leaven positive on 5% NAS. PCR was carried out for 62 P. syringae isolates for detection of Pss , using syrB primer with size 752 bp. Results showed that 13 of 62 (21%) isolates carried syrB gene and similarly in the biochemical characters using Analytical Profile Index (API 20NE). Thus, characterization of Pss strains to hydrolysis Esculin, Gelatin and fruit contents of Glucose, Arabinose, Mannose, Mannitol, Capric and Malic acid. Other biochemical analysis was also documented. PCR identification of Pss considers the first certified record for these suspected and serious phytopathogenic bacteria in Iraq.