Deciphering the dual effect oflipopolysaccharides from plant pathogenicPectobacterium

摘要

Lipopolysaccharides (LPS) are a component of the outer cell surface of almost all Gram-negative bacteria and play anessential role for bacterial growth and survival. Lipopolysaccharides represent typical microbe-associated molecularpattern (MAMP) molecules and have been reported to induce defense-related responses, including the expression ofdefense genes and the suppression of the hypersensitive response in plants. However, depending on their origin andthe challenged plant, LPS were shown to have complex and different roles. In this study we showed that LPS from plantpathogensPectobacterium atrosepticumandPectobacterium carotovorum subsp. carotovoruminduce common anddifferent responses inA. thalianacells when compared to those induced by LPS from non-phytopathogensEscherichiacoliandPseudomonas aeruginosa. Among common responses to both types of LPS are the transcription of defensegenes and their ability to limit of cell death induced byPectobacterium carotovorum subsp carotovorum. However, thedifferential kinetics and amplitude in reactive oxygen species (ROS) generation seemed to regulate defense genetranscription and be determinant to induce programmed cell death in response to LPS from the plant pathogenicPectobacterium. These data suggest that different signaling pathways could be activated by LPS inA. thalianacells.