Etiological study of sour cherry fruits bacterial necrosis in south Banat

Abstract

Characteristics of pathogenic Pseudomonas bacterial strains isolated from necrotic sour cherry fruits (Kelleris 14) in region of south Banat. First symptoms of disease appeared as dark green wet spot. Later on it turns to brown or black sunken necrosis. During rainy spring percent of affected fruits reached up 60-80. Gram negative, fluorescent, oxidative bacterial strains were isolated from the margin of necrotic tissue. All investigated strains are levan and HR positive, while negative results are recorded in oxidase, pectinase and arginin dihydrolase tests (LOPAT+- - - +). Investigated strains cause severe necrosis of artificially sour cherry fruits (Kelleris 14) as well as necroses on artificially inoculated cherry, pear and lemon fruits, lilac leaves and bean pods. Positive results were recorded in gelatin and aesculin hydrolysis tests while, tyrosinase and tartrate tests were negative (typical characteristics of P.s. pv.syringae). According the obtained results it was concluded that severe necrosis of sour cherry fruits (Kelleris 14) in South Banat is caused by Pseudomonas syringae pv syringae.

U radu su saopštene karakteristike izolata bakterije Pseudomonas syringae izolovane iz nekrozom zahvaćenih plodova višnje (Kelleris 14) na području Južnog Banata. Simptomi sa karakterističnim crnomrkim ulegnutim nekrozama prikupljani su u periodu 2008-2010 godine. Iz obolelog tkiva izolavani su gramnegativni, fluorescentni sojevi bakterija, koji glukozu metabolišu isključivo u aerobnim uslovima (oksidativno); prouzrokuju HR duvana i stvaraju levan, ali ne proizvode oksidazu, pektinazu i arginindehidrolazu (LOPAT I). Proučeni izolati prouzrokuju nekrozu plodova višnje, trešnje, kruške i limuna, listova jorgovana i mahuna boranije. U pogledu diferencijalnih testova za patogene varijetete P. syringae, rezultati ukazuju da dobijeni sojevi hidrolizuju želatin i eskulin, ali ne stvaraju tirozinazu i ne metabolišu tartarate. Na osnovu dobijenih rezultata i odlika izolovanih sojeva zaključeno je, da nekrozu plodova višnje veoma visokog intenziteta, zapaženu poslednjih godina u Južnom Banatu, prouzrokuje bakterija Pseudomonas syringae pv. syringae.