Characterization of Pectobacterium carotovorum subsp. carotovorum isolates from a recent outbreak on cabbage in Bosnia and Herzegovina

Abstract

The causal agent of soft rot disease associated with a cabbage outbreak in Semberija region, Bosnia and Herzegovina, in 2018 was identified and characterized. Symptoms appeared in the form of water-soaked lesions on leaves and specific odour. Disease incidence ranged from 20% to 30%. The causal pathogen was isolated on nutrient agar (NA), King?s B and crystal violet pectate (CVP) media. Eight creamy-white, round and convex bacterial isolates, which produced characteristic pits on CVP medium were taken as representative. They were gram negative, facultative anaerobe, oxidase negative, catalase positive, nonfluorescent on King?s B medium, levan and arginine dehydrolase negative. The isolates were able to cause soft rot on cabbage and potato tuber slices 24 h after inoculation under conditions of high relative humidity. Polymerase chain reaction (PCR) was performed for preliminary identification by using three specific primer sets: F0145/E2477 (specific for Pectobacterium carotovorum subsp. carotovorum), Br1f/L1r (specific for P. carotovorum subsp. brasiliensis) and ECA1f/ECA2r (specific for P. atrosepticum). All isolates produced the band size of 666 bp with F0145/E2477 primer pair, indicating that they belong to the species P. carotovorum subsp. carotovorum. Further genetic characterization was based on sequence analysis of the gapA and mdh housekeeping genes. BLAST analysis confirmed 99.39% (Q. cover 100%, E. value 0.0) and 100% (Q. cover 100%, E. value 0.0) identity of the isolates with P. carotovorum subsp. carotovorum strains deposited in the NCBI database as M34 (KY047594) for gapA and Pcc t0437 (KC337296) for mdh genes, respectively. Phylogenetic analysis showed genetic homogeneity among the cabbage isolates. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III43010]

Diversity of Bacterial Soft Rot-Causing Pectobacterium Species Affecting Cabbage in Serbia

“…However, the extent of yield loss is influenced by pathogen−host specificity, as well as numerous external factors (temperature, humidity, etc.) [ 8 ]. Although bacterial soft rot is a disease that affects only agricultural and horticultural crops, the presence of the soft rot-causing Pectobacteriaceae is not only limited to host plants but extends to the weed species growing near the infected fields, as well as water, air, and soil, thus serving as a potent source of inoculum [ 9 ].…”

Encapsulated Clove Bud Essential Oil: A New Perspective as an Eco-Friendly Biopesticide

“…The CEO is known to be effective against soft rot bacteria [36][37][38], as well as in general against both Gram-positive and Gram-negative bacteria [57]. We found that MIC (or minimum bactericidal concentrations, MBC) of CEO was 1% concentration in controlling soft rot pathogens.…”

“…All strains belong to the laboratory collection of the Institute for Plant Protection and Environment, and were originated from cabbage in case of P. carotovorum subsp. carotovorum strain Pcc10 [38], and potato in case of strains of P. carotovorum subsp. brasiliensis Pcb62 and D. dianthicola Dd31 [39].…”

“…brasiliensis Pcb62 and D. dianthicola Dd31 [39]. All strains were molecularly identified [38,39]. For the experiments, strains were grown on Nutrient Agar (NA) for 48 h at 26 • C. The inhibitory effect was evaluated by Agar well diffusion method using holes in the medium [44].…”

“…Therefore, biological activity will be tested on selected pests and pathogens, which can be found in the open field as well as in storage conditions, (i) potato tuber moth Phthorimaea operculella Zeller [32], as one of the most destructive pests of Solanaceae, (ii) gray mold fungi pathogen Botrytis cinerea, that infects fruits (pome, stone), berries, grapes, and several vegetable species [17,30,[33][34][35], and (iii) soft rot bacterial pathogens Pectobacterium carotovorum (subsp. carotovorum and brasiliensis) and Dickeya dianthicola destructive on a wide range of plants [36][37][38][39][40]. All of these harmful organisms with broad-host-range are widely present in Serbia and known to cause severe losses on attacked plant hosts.…”