A Molecular Insight into the Occurrence Colonization and Interaction of Human Pathogenic Bacteria with Solanum Lycopersicum

Abstract

During last two decades an increasing number of gastrointestinal outbreaks related to consumption of raw and contaminated fresh farm produce including tomato, radish, sprouts, lettuce, cucumber, leafy greens etc. have been reported from Canada, US and European countries. Epidemical studies have revealed that an array of human enteric pathogens (HEPs) colonize edible plant parts. The present study provides an insight into the extent of HEPs colonizing such organically grown fruits and vegetables. The study of molecular aspects of adaptations of these microbes on plant surfaces and their interactions with other microbes are extremely important to understand how these microbes that are adapted to colonize human gastrointestinal tract can effectively survive and colonize on plant surfaces. Such studies should help in developing suitable strategies for controlling HEPs on fresh farm produce. In the present study vegetable samples were collected from fields utilizing animal dung based manure and contaminated water for crop cultivation. Radish (Raphanus sativus) and tomato (Solanum lycopersicum) were selected for the study as these vegetables are commonly consumed raw as salads in India. Human pathogenic bacteria contaminating edible parts of the two vegetables were isolated and identified. Their colonization and adherence pattern on leaf surface of tomato were investigated to understand the extent of their persistence and respective pathogen load. Antibiotic susceptibility of identified pathogens was tested to understand the clinical significance and potent health concerns related to the consumption of such contaminated vegetables. To understand the epiphytic fitness of HEPs, effect of their colonization on defense response of tomato was studied. The presence of an HEP primes the defense response in tomato plant against infection by P. syringae pv. tomato thereby making it healthy and disease free to ensure the colonization and survival of HEP. newline