Community Structure of Actively Growing Bacterial Populations in Plant Pathogen Suppressive Soil

Abstract

The bacterial community in soil was screened by using various molecular approaches for bacterial populations that were activated upon addition of different supplements. Plasmodiophora brassicae spores, chitin, sodium acetate, and cabbage plants were added to activate specific bacterial populations as an aid in screening for novel antagonists to plant pathogens. DNA from growing bacteria was specifically extracted from the soil by bromodeoxyuridine immunocapture. The captured DNA was fingerprinted by terminal restriction fragment length polymorphism (T-RFLP). The composition of the dominant bacterial community was also analyzed directly by T-RFLP and by denaturing gradient gel electrophoresis (DGGE). After chitin addition to the soil, some bacterial populations increased dramatically and became dominant both in the total and in the actively growing community. Some of the emerging bands on DGGE gels from chitin-amended soil were sequenced and found to be similar to known chitin-degrading genera such as Oerskovia, Kitasatospora, and Streptomyces species. Some of these sequences could be matched to specific terminal restriction fragments on the T-RFLP output. After addition of Plasmodiophora spores, an increase in specific Pseudomonads could be observed with Pseudomonas-specific primers for DGGE. These results demonstrate the utility of microbiomics, or a combination of molecular approaches, for investigating the composition of complex microbial communities in soil.

Molecular Fingerprinting of the Fecal Microbiota of Children Raised According to Different Lifestyles

“…(Amersham Biosciences). The efficiency of restriction digestion was confirmed by agarose gel electrophoresis, and the digested fragments were separated on an ABI 3700 capillary sequencer, as described previously (16). The sizes of the fluorescently labeled fragments were determined by comparison with the internal GS ROX-500 size standard (ABI).…”

Molecular analysis of the gut microbiota of identical twins with Crohn's disease

“…Terminal-restriction fragment length polymorphism PCR products were digested with the HaeIII restriction enzyme (GE Healthcare, Uppsala, Sweden) and the digested fragments were separated on an ABI 3700 capillary sequencer (ABI Applied Biosystems, Foster City, CA, USA), as described previously (Hjort et al, 2007). The sizes of the fluorescently labeled fragments were determined by comparison with the internal GS ROX-500 size standard (ABI).…”

Microbial community diversity analysis of <i>Panax ginseng</i> rhizosphere and non-rhizosphere soil using randomly amplified polymorphic DNA method

“…Unfortunately, the importance of rhizosphere microbial diversity is almost unknown. More recently, there is an increasing interest in the analysis of soil microbial community structure [7,8]. Among different methods, Random Amplified Polymorphic DNA (RAPD), has been widely used in species classification and phylogenetic analysis [9], species identification [10], and genetic analysis of populations [11].…”