Microorganisms in the rhizosphere of wheat colonized by the fungusGaeumannomyces graminis var.tritici

Publisher Website
Google Scholar
Abstract
The population of microorganisms in wheat rhizosphere changed in the presence of the fungusGaeumannomyces graminis var.tritici causing the take-all of wheat. In the majority of cases when the soil was artificially contaminated by the fungus, both the number of bacteria in the rhizosphere and the bacteria/ fungi ratio temporarily increased. At the beginning bacteria growing in the presence of NE4 + predominated, later bacteria utilizing organic N-substances prevailed.Pseudomonas fluorescens and the related species colonized the rhizosphere and the soil to a greater extent in the presence ofG. graminis. The wheat rhizosphere withG. graminis was found to contain a higher level of the slime-producing bacteriumAgrobacterium spp.; this microorganism occurred on hyphal surfaces (in hyphosphere) of bothG. graminis growing in soil andMucor spp. Changes in microbial populations in the wheat rhizosphere during the first stage of colonization byG. graminis can be partly explained by a simultaneous rhizosphere colonization by microorganisms which accompany this fungus in soil. In the period of increase in the number of bacteria in rhizosphere a temporary stimulation of wheat growth was observed.