Identification of the causal agent of bacterial canker on hazelnut trees in Guilan province

Document Type : Short paper

Authors

Abstract

Two species of Pseudomonas bacteria including P. avellanae and P. syringae pv. syringae have been identified till now as pathogenic agents on hazelnut trees. During the year 2004, hazelnut trees of Guilan province were visited and samples were taken from trees showing suspicious symptoms. After culturing extracts of the infected tissues on NA and King’s B media, dark white, fluorescent colonies were isolated. The isolates were gram negative, oxidase and pectinase negative, Levan and catalase positive and obligate oxidative. They caused hypersensitive reaction on tobacco leaves and could not hydrolyze gelatin. Based on these characteristics, isolates were identified as the genus Pseudomonas. The isolates had the ability to produce ice nucleation and syringomycin toxon, but they could not produce indole, reduce nitrate, produce H2S, tolerate NaCl 7% and hydrolyze starch, but they hydrolyzed Tween 80 and casein. The isolates also could use tartarate, L-cystein, lysin, lactose, rhamnose, maltose, L-arabinose, ribose, glycin, triptophan and dextrin, but they used D-sorbitol, rafinose, trehalose and sucrose. Pathogenicity test of isolates on leaves, fruit and buds of hazelnut branches was also positive. Based on all physiological and biochemical characteristics, the isolates were identified as P. syringae pv. syringae. Comparison of protein profile of isolates with reference strain of this pathovar also showed a high similarity percentage. Pathogenicity of this pathovar on hazelnut trees in Guilan province was proved for the first time as a result of the current research. P. avellanae was not observed and isolated from any of the suspected samples and existence of it was not proved in this province.
 
 

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-       حسن زاده، ن. و مهدویان، س. ا. 1377. جداسازی باکتری Pseudomonas syringae از فندق. خلاصه مقالات سیزدهمین کنگره گیاهپزشکی ایران. صفحه 242.
-       Janse, J.D., Rossi, P., Angelucci, L., Scortichini, M., Derks, J.H.J., Akkermans, A.D.L., de Vrijer, R. and Psallidas, P.G. 1996. Reclassification of Pseudomonas syringae pv. avellanae as Pseudomonas avellanae (spec. nov.), the bacterium causing canker of hazelnut (Corylus avellana L.). Systematic and Applied Microbiology, 19, 4: 589-595.
-       Jones, A. L., 1971. Bacterial canker of sweet cherry in Michigan. Plant disease, 55: 961-965.
-       Laemmli, U.K. 1970. Cleavage of structural proteins during assembly of the head of bacteriophage T4. Nature, 227: 680-685.
-       Psallidas, P.G. 1993. Pseudomonas syringae pv. avellanae pathovar nov., the bacterium causing canker disease on Corylus avellana. Plant Pathology, 42: 358-363.
-       Psallidas, P.G. and Panagopoulos, C.G. 1979. A bacterial canker of hazelnut in Greece. Phytopathol. Z. 94: 103-111.
-       Schaad, N.W., Jones, J.B. and Chun, W. 2001. Laboratory Guide for Identification of Plant Pathogenic Bacteria, (Third edition) St. Paul, MN, APS Press, 373 pp.
-       Scortichini, M. 1999. Hazelnut tree decline. Rivista di Fruticoltura e di Ortofloricoltua, 61,11: 40-42.
-       Scortichini, M. 2002. Bacterial canker and decline of European Hazelnut. Plant disease, 86, 7: 704-709.
-       Scortichini, M. and Mehlenbacher, S.A. 2001. The problem caused by Pseudomonas avellanae on hazelnut in Italy. Proceedings of the Fifth International Congress on Hazelnut: Acta Horticulturae, 556: 503-508.
-       Scortichini, M. and Tropiano, F.G. 1994. Severe outbreak of Pseudomonas syringae pv. avellanae on hazelnut in Italy. Journal of Phytopathology, 140,1: 65-70.
-       Yessad, S., Manceau, C. and Luisetti, J. 1992. A detached leaf assay to evaluate virulence and pathogenicity of strains of Pseudomonas syringae on Pear. Plant disease, 76,4: 370-373.
-       Young, J.M. 1991. Pathogenicity and identification of the lilac pathogen, Pseudomonas syringae pv. syringae Van Hall 1902. Ann. Appl. Biol., 118: 283-298.