Pseudomonas syringae pv. glycinea economically harmful pathogen of soybean in Vojvodina

Abstract

Pseudomonas syringae pv. glycinea (Coerper) Young causal agent of bacterial blight is important and frequent disease of soybean in Vojvodina province. Isolation of the pathogen was carried out during 2005. from infected soybean leaves of several cultivar. Pathogenicity of the obtained isolates including referent strain (National Collection of Plant Pathogenic Bacteria, United Kingdom-NCPPB 3318) was proved by inoculation soybean plants at cotyledon stage (Balkan variety) and by hypersensitive reaction (HR) on tobacco leaves. Cultural and biochemical-physiological characteristics were tested according to known methods. Bacterium identification was also confirmed by serological method (agglutination tests, IF, ELISA,) with appropriate antibodies of P. s. pv. glycinea NEOGEN Europe Ltd., Scotland, UK. All investigated isolates showed positive reaction with mentioned antibodies. Molecular technique (PCR) based on chlorosis inducing phytotoxin coronatine confirm that studied isolates belong to P. s. pv. glycinea. Differential soybean cultivars: Acme, Chippewa, Flambeau, Harosoy, Lindarin, Merit and Norchief were used to determine physiological race of the bacterium. Young plants were inoculated in two ways: by leaves rubbing with sterile cotton swab dipped into the bacterial suspension and by spraying leaves under the pressure. Based on the obtained results it was shown that strains which cause bacterial blight of soybeans in Vojvodina, belonged to P. s. pv. glycinea race 4. Reaction of 12 soybean varieties and two lines (L-220 230, P-9241) from different maturity groups were investigated under natural field infection and under glass house conditions. Statistically significant differences of sensitivity between individual genotypes and lines were determined. Genotypes 000 and 00 maturity group were the most sensitive.

Bakteriozna pegavost soje, čiji je prouzrokovač Pseudomonas syringae pv. glycinea (Coerper) Young, u Srbiji se javlja redovno, često u jakom intenzitetu. Uzorci su prikupljeni tokom 2005. godine, iz više lokaliteta u Vojvodini. Patogenost dobijenih izolata je dokazana pozitivnom hipersenzitivnom reakcijom (HR) na duvanu, kao i inokulacijom biljaka soje u fazi kotiledona (sorta Balkan). Odgajivačke i biohemijsko-fiziološke odlike ispitane su standardnim metodama. Na osnovu dobijenih rezultata, ispitivani izolati poseduju karakteristike Ia fluorescentne grupe fitopatogenih bakterija roda Pseudomonas. Za razlikovanje P. s. pv. syringae od P. s. pv. glycinea korišćeni su specijalni diferencijalni testovi. Rezultati ukazuju da prvi patogen koristi eritritol, betain, sorbitol i L-laktat, izazivajući nekrozu zelenih plodova višnje i trešnje, dok P. s. pv. glycinea pokazuje negativnu reakciju u pomenutim testovima. Identifikacija bakterija potvrđena je i serološkim testovima (metod aglutinacije, IF, ELISA), korišćenjem odgovarajućih antitela bakterije P. s. pv. glycinea, (NEOGEN Europe Ltd., Scotland, UK). Molekularnom metodom identifikacije (PCR), korišćenjem odgovarajućih prajmera, potvrđeno je da proučeni izolati sa soje pripadaju vrsti P. s. pv. glycinea. Pripadnost dobijenih izolata fiziološkim rasama određena je korišćenjem diferencijalnog sortimenta soje: Acme, Chippewa, Flambeau, Harosoy, Lindarin, Merit i Norchief. Zaključeno je da izolati bakterije P. s. pv. glycinea, sa soje u Vojvodini, pripadaju rasi 4. Reakcija 12 sorti i dve linije soje (L-220 230, P-9241), različitih grupa zrenja, prema P. s. pv. glycinea, ispitana je u uslovima spontane infekcije u polju i staklari. Genotipovi soje, obuhvaćeni ovim proučavanjima, ispoljili su različit nivo osetljivosti prema P. s. pv. glycinea. Postoje statistički značajne razlike osetljivosti između pojedinih genotipova i linija. Genotipovi sa najkraćom vegetacijom (000 i 00 grupa zrenja) pokazali su se kao najosetljiviji.