Molecular Insight Into Cross Talks Between Phylloplane Microflora and Human Enteric Pathogen on Leaf Surface

Abstract

Phyllosphere is colonized by an array of micro-organisms like bacteria, fungi, yeasts, newlinealgae, protozoa etc. The bacterial population may include species pathogenic or nonpathogenic newlineto plants. Contamination of fresh produce like tomato, sprouts, lettuce, radish, newlinecucumber etc. Farmyard manure and irrigation water is considered to be the primary source of newlinecontamination. The HEPs enter the human system through consumption of such newlinecontaminated fresh farm produce. The study is important to understand their adaptation and molecular interaction with host plant. The cross talk study would be helpful in newlinedeveloping strategies to limit the growth of HEPs on edible plant parts and newlinesubsequently in the reduction of food-borne outbreaks. newlineIn the present study human enteric pathogens have been isolated from the leaves and newlinefruits surface of field grown tomato (Solanum lycopersicum). newlineColonization pattern and biofilm formation was studied by inoculating naturally newlinegrowing plants with individual bacterial species as well as their combinations. newlineThe results revealed the presence of Serratia fonticola, Klebsiella pneumoniae and Chryseobacterium jejuense from the phylloplane and fructoplane of field grown newlinetomato plants. Colonization assay demonstrated varying results by individual bacteria newlineand their combination.UPLC-MS studies led to identification of different newlineacyl homoserine lactone molecules in these HEPs. Two AHLs were found common in newlineall three bacteria and selected for in silico interaction with the LuxR protein. AHL newlinemolecules were found to interact at different ligand binding sites which are the amino newlineacid moieties on the protein. The presence of AHL signal molecules and subsequent biofilm formation leads to their successful colonization the phylloplane of tomato. The HEPs multiply and increase their density on a non-host environment and overcome the environmental newlinestress. As the leaves mature, the pathogens persisting on the leaves enter the fruits and newlinefind their way to into human system on consumption of contaminated fruits. Control newlineand disruption of biofilms on phylloplane can help in reduction of human pathogen newlineload and thereby decreasing the incidences of gastrointestinal disorders. newline newline