Cross-Over Pathogenic Bacteria Detected in Infected Tomatoes (Solanum lycopersicum L.) and Peppers (Capsicum annuum L.) in Bulgaria

Abstract

The ability of certain human pathogens to adapt to plants without losing their virulence toward people is a major concern today. Thus, the aim of the present work was the investigation of the presence of cross-over pathogenic bacteria in infected tomato and pepper plants. The objects of the study were 21 samples from seven different parts of the plants and three from tomato rhizosphere. In total, 26 strains were isolated, identified by MALDI-TOF, and phenotypically characterized. The PCR amplification of the rpoB gene was applied as an approach for the rapid detection of cross-over pathogens in plant samples. A great bacterial diversity was revealed from tomato samples as nine species were identified (Leclercia adecarboxylata, Pseudesherichia vulneris, Enterobacter cancerogenus, Enterobacter cloacae, Enterobacter bugandensis, Acinetobacter calcoaceticus, Pantoea agglomerans, Pantoea ananatis, and Pectobacterium carotovorum). Polymicrobial contaminations were observed in samples T2 (tomato flower) and T10 (tomato fruit). Five species were identified from pepper samples (P. agglomerans, L. adecarboxylata, Pseudomonas sp., Pseudomonas putida, and Enterococcus sp.). Antibiotic resistance patterns were assigned in accordance with EFSA recommendations. All isolates showed varying resistance to the tested antibiotics. The genetic basis for the phenotypic antibiotic resistance was not revealed. No genes for the virulence factors were found among the population. To our knowledge, this is the first overall investigation of tomato and pepper cross-over pathogenic bacterial populations in Bulgaria.

Novel Endophytic Pseudescherichia sp. GSE25 Strain Significantly Controls Fusarium graminearum and Reduces Deoxynivalenol in Wheat

“…The strain GSE25 is a gram-negative bacterium and phenotypically challenging to distinguish from the family Enterobacteriaceae and other Pseudescherichia vulneris species based on 16S rRNA sequence similarity. It has been reported that P. vulneris was detected in several clinical isolates and had the potential to cause diarrheal illness by examining the genes for enterotoxins and exotoxin [ 19 , 20 , 21 ]. To ensure the availability and biosafety of GSE25 on crops, we tested the virulence factors and hemolysis of GSE25.…”

Pathogenic Potential and Antibiotic Susceptibility: A Comprehensive Study of Enterococci from Different Ecological Settings

“…The isolates were identified by three different methods: PCR with genus-and speciesspecific primers [46,47], 16S rRNA sequencing [46], and MALDI-TOF (Matrix-Assisted Laser Desorption/Ionization Time-of-Flight) mass spectrometry [8]. Genus-and species-specific PCRs were performed in a total reaction volume of 25 µL containing 16.5 µL ultrapure H 2 O, 0.5 µL (5 pmol/µL) of each primer, 6.5 µL VWR Red Taq polymerase master Mix (VWR International bvba/sprl, Haasrode Researchpark Zone 3, Geldenaaksebaan 464 B-3001, Haasrode Belgium), and 1 µL extracted DNA.…”

“…This genus of bacteria forms a part of natural biomes of soil, water, sewage, and arable land, as well as populations in the gastrointestinal tracts (GITs) of mammals, birds, fishes, invertebrates, and insects [2][3][4][5][6]. Similarly, enterococci have been isolated from fresh vegetables (olive, pepper, celery, cilantro, mustard greens, spinach, collards, parsley, dill, cabbage, and cantaloupe) and wild plants also [7][8][9][10]. Flowering plants and crops have also been known to be carriers of enterococci [11].…”

“…However, most studies assume that enterococci, as part of the natural microbiota of the gastrointestinal tract of warm-blooded animals, can enter the environment through feces, contaminate soil and water, and then colonize plants. This pathway explains why enterococci predominate on plant surfaces and are resistant to a number of antibiotics [17][18][19][20], but at the same time, they can be identified as potential cross-over agents promoting the dissemination of antibiotic resistance [8,21]. Furthermore, it has been suggested that the infection strategies of some enterococci (E. faecalis) are similar in plants, mammals, and nematodes [1].…”

“…E. faecalis has developed a significant biofilmlike pathogenic community that has colonized the root surface [1]. Enterococci have been previously reported as a component of the microbiome of pepper plants with symptoms of disease [8].…”