Rhizospheric and endophyticPseudomonas aeruginosain edible vegetable plants share molecular and metabolic traits with clinical isolates

Abstract

Pseudomonas aeruginosa, a leading opportunistic pathogen causing hospital-acquired infections is predominantly present in agricultural settings. There are minimal attempts to examine the molecular and functional attributes shared by agricultural and clinical strains of P. aeruginosa. This study aims to investigate the presence of P. aeruginosa in edible vegetable plants (including salad vegetables) and analyze the evolutionary and metabolic relatedness of the agricultural and clinical strains. Eighteen rhizospheric and endophytic P. aeruginosa strains were isolated from cucumber, tomato, eggplant, and chili directly from the farms. The identity of these strains was confirmed using biochemical, and molecular markers and their genetic and metabolic traits were compared with clinical isolates. DNA fingerprinting analyses and 16S rDNA-based phylogenetic tree revealed that the plant- and human-associated strains are evolutionarily related. Both agricultural and clinical isolates possessed plant-beneficial properties, including mineral solubilization (phosphorous, potassium, and zinc), ammonification, and the ability to release extracellular siderophore and indole-3 acetic acid. These findings suggest that rhizospheric and endophytic P. aeruginosa strains are genetically and functionally analogous to the clinical isolates. This study highlights the edible plants as a potential source for human and animal transmission of P. aeruginosa.

Pathogenesis of plant-associated Pseudomonas aeruginosa in Caenorhabditis elegans model

“…So far, there have been minimal works on the biosafety of plant-associated P. aeruginosa strains [16]. Our previous studies identi ed that agricultural P. aeruginosa strains harboring plant-bene cial traits could also exhibit virulence and pathogenicity [11,12]. The present work identi ed the critical virulence factors that contribute to the eukaryotic pathogenesis of plant-associated P. aeruginosa using the C. elegans model system.…”

“…Strains and culture conditions Plant-associated P. aeruginosa strains used in this study were previously isolated by the authors from cucumber, tomato, eggplant, and chili [Table 2; [11]]. Clinical P. aeruginosa strains, PAO1, ATCC10145, and ATCC9027, were used as positive controls for pathogenicity assays [31][32][33].…”

“…Chili Endophyte [11] incubation, A660 was measured (Spectramax® i3x, USA) to estimate the planktonic population. Bio lm attached to the microtitre wells was washed with sterile water and drenched with 300 µl of 0.1 % crystal violet.…”

“…In addition, all the strains inhibited the growth of bacterial and fungal phytopathogens, including Xanthomonas oryzae, Pythium aphanidermatum, Rhizactonia solani, and Fusarium oxysporum [12]. However, these plant-associated strains had several virulence traits, such as the production of pyocyanin, rhamnolipid, and siderophore, bio lm formation, swarming motility, and multiple lytic activities [11,12]. In the current work, we hypothesized that one of these virulence factors could be used as a biomarker to detect the pathogenicity level of P. aeruginosa in agricultural systems.…”

“…In our previous study, we isolated and characterized P. aeruginosa strains (PPA01-PPA18) from rhizospheric and endophytic niches of cucumber, tomato, eggplant, and chili harvested from different farms [11]. These strains had plant-bene cial traits such as mineral solubilization and plant-growth hormone production.…”