Endophytic Bacteria Pseudomonas aeruginosa PM389 Subsists Host’s (Triticum aestivum) Immune Response for Gaining Entry Inside the Host

Abstract

The present study was designed to compare the defense response of the host plant towards endophytic bacteria Pseudomonas aeruginosa PM389 and pathogenic bacteria Erwinia carotovora and to correlate the level of defense enzymes vis-a-vis bacterial colonization in the host. Wheat seedlings were treated with 107-108 cells ml-1 endophytic and pathogenic bacteria in the separate experimental set-up, and the level of plant defense enzyme was measured at various time intervals. Comparatively reduced level of most defense enzymes was produced in endophytic bacteria treated plants. While the endophytic bacterial population was almost constant after 24 HAI (hour after inoculation), the population of pathogenic bacteria kept fluctuating during the study period from 24 HAI. Unlike pathogenic bacteria, we observed attenuated defense response in challenged host plants towards endophytic bacteria, which helps endophytes establish inside plant. This study would be useful for understanding the mechanism of colonization and strategies of endophytes to fight against the host defense response.