Location ofXanthomonas translucensin pistachio trees

Abstract

Xanthomonas translucens has been identified as the causal agent of pistachio dieback in Australia. Symptoms include decline, xylem staining, trunk and limb lesions, and excessive exudation of resin. Bacteria were previously isolated from stained wood in 2 year old twigs but little was known about their presence in other parts of the tree. The pattern of staining and location of X. translucens were studied following felling and dissection of asymptomatic and diseased trees. Chestnut-coloured smears and specks occurred in the 3 sapwood of diseased trees and were continuous from the trunk to 1-2 year old twigs. Xanthomonas translucens was isolated mainly from young sapwood (stained and unstained) of the main trunk, primary and younger branches and current season growth, less frequently from leaves and bunches, rarely from old, stained heartwood and not from roots and associated soil samples. Bacteria and pathogenic fungi were not found in the inner bark and cortex associated with lesions whereas the stained sapwood underlying the lesions yielded X. translucens. Scanning electron microscopy revealed bacteria in the main vessels of the xylem of stained tissue and tyloses in the proximity of colonised tissue. Information on the pattern of staining and location of the bacteria will facilitate pathogen detection, thereby improving the accuracy of disease diagnosis.

Characterization of the Xanthomonas translucens Complex Using Draft Genomes, Comparative Genomics, Phylogenetic Analysis, and Diagnostic LAMP Assays

“…undulosa has been isolated from ornamental asparagus, and a newly proposed pathovar, X. translucens pv. pistachiae, isolated from pistachio orchards, is virulent on a number of hosts outside of its natural host range (Adhikari et al 2012;Bull et al 2012;Facelli et al 2009;Marefat et al 2006;Rademaker et al 2006).…”

Effect of burning and high temperature on survival of Xanthomonas translucens pv. pistaciae in infected pistachio branches and twigs

“…, 2009), occurs mainly in woody tissue of the scion, Pistacia vera , where it usually induces staining of the xylem. The bacterium has been isolated less frequently from the rootstock, generally Pistacia integerrima (Facelli et al. , 2009).…”

“…, 2009). The distribution of Xtp in pistachio wood is often discontinuous, while the bacterium has been isolated from leaves only rarely and not from roots or associated soil samples (Facelli et al. , 2009).…”

“…pistaciae (Xtp) (Giblot-Ducray et al, 2009), occurs mainly in woody tissue of the scion, Pistacia vera, where it usually induces staining of the xylem. The bacterium has been isolated less frequently from the rootstock, generally Pistacia integerrima (Facelli et al, 2009). The distribution of Xtp in pistachio wood is often discontinuous, while the bacterium has been isolated from leaves only rarely and not from roots or associated soil samples (Facelli et al, 2009).…”

“…The bacterium has been isolated less frequently from the rootstock, generally Pistacia integerrima (Facelli et al, 2009). The distribution of Xtp in pistachio wood is often discontinuous, while the bacterium has been isolated from leaves only rarely and not from roots or associated soil samples (Facelli et al, 2009). Although the natural means of survival and dissemination are not known, transmission of Xtp via pruning has been demonstrated .…”