Rhizosphere Microbial Community Dynamics

Kapoor, Roopam; Mukerji, K. G.

doi:10.1007/3-540-29420-1_4

Cited by 10 publications

(6 citation statements)

References 54 publications

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“…Signal molecules exchanged between plants and microorganisms have been identified that favor beneficial plant colonization [21] . Plant roots might develope defence strategies by secreting compounds into the rhizosphere that interfere with bacterial quorum sensing responses [22] . However, motile bacteria could respond to environmental cues or a specific plant to move to more favorable locations [23] .…”

Section: Discussionmentioning

confidence: 99%

Comparative Metaproteomic Analysis on Consecutively Rehmannia glutinosa-Monocultured Rhizosphere Soil

et al. 2011

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BackgroundThe consecutive monoculture for most of medicinal plants, such as Rehmannia glutinosa, results in a significant reduction in the yield and quality. There is an urgent need to study for the sustainable development of Chinese herbaceous medicine.Methodology/Principal FindingsComparative metaproteomics of rhizosphere soil was developed and used to analyze the underlying mechanism of the consecutive monoculture problems of R. glutinosa. The 2D-gel patterns of protein spots for the soil samples showed a strong matrix dependency. Among the spots, 103 spots with high resolution and repeatability were randomly selected and successfully identified by MALDI TOF-TOF MS for a rhizosphere soil metaproteomic profile analysis. These proteins originating from plants and microorganisms play important roles in nutrient cycles and energy flow in rhizospheric soil ecosystem. They function in protein, nucleotide and secondary metabolisms, signal transduction and resistance. Comparative metaproteomics analysis revealed 33 differentially expressed protein spots in rhizosphere soil in response to increasing years of monoculture. Among them, plant proteins related to carbon and nitrogen metabolism and stress response, were mostly up-regulated except a down-regulated protein (glutathione S-transferase) involving detoxification. The phenylalanine ammonia-lyase was believed to participate in the phenylpropanoid metabolism as shown with a considerable increase in total phenolic acid content with increasing years of monoculture. Microbial proteins related to protein metabolism and cell wall biosynthesis, were up-regulated except a down-regulated protein (geranylgeranyl pyrophosphate synthase) functioning in diterpenoid synthesis. The results suggest that the consecutive monoculture of R. glutinosa changes the soil microbial ecology due to the exudates accumulation, as a result, the nutrient cycles are affected, leading to the retardation of plant growth and development.Conclusions/SignificanceOur results demonstrated the interactions among plant, soil and microflora in the proteomic level are crucial for the productivity and quality of R. glutinosa in consecutive monoculture system.

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Section: Discussionmentioning

confidence: 99%

Comparative Metaproteomic Analysis on Consecutively Rehmannia glutinosa-Monocultured Rhizosphere Soil

et al. 2011

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Section: Introductionmentioning

confidence: 99%

“…It has therefore become increasingly important to investigate the bacterial community of unprocessed plant foods such as fresh herbs. To date, little is known about the microbial community of fresh herbs and its development, whereas many studies have investigated properties of various fresh herb ingredients like essential oils or have focused on the plants' rhizosphere (Kapoor and Mukerji 2006;Tamilarasi et al 2007;Bafana 2013;Solaiman and Anawar 2015). In order to understand the bacterial community development of fresh herbs' phyllosphere, it is important to analyse their production environment, which shapes the plant host's bacterial community (Knief et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Dynamics of culturable mesophilic bacterial communities of three fresh herbs and their production environment

et al. 2017

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Aim: Investigate dynamics of culturable mesophilic bacteria and selected foodcontaminating bacteria from three herbs and their production environment. Methods and Results: Marjoram, basil and thyme were investigated during one growing season by sampling plants, organic fertilizers, soil, irrigation water and marketed products. Mesophilic bacteria and selected food-contaminating bacteria (Escherichia coli, Enterococcus spp., Bacillus cereus group) were cultured and identified by MALDI biotyping. Culturable mesophilic bacteria on marjoram and basil plants decreased over time by two orders of magnitude starting at above 10 6 colony forming units per gram (CFU per g), while they remained constant on thyme (~10 4 CFU per g). Compared to the last field sample, mesophilic bacteria were increased on all market-ready products by one order of magnitude. Marjoram and basil were dominated by B. cereus group, Enterobacter spp. and Pseudomonas spp., thyme by Bacillus spp. and Pseudomonas spp. All selected food-contaminating bacteria were detected in soil and reservoir-sourced irrigation water, whereas in municipal water, only B. cereus group and rarely Enterococcus spp. were found. Escherichia coli was detected only on young marjoram and basil plants (5 9 10 2 and 5 9 10 1 CFU per g, respectively), whereas Enterococcus spp. and B. cereus group were consistently detected on these two herbs. Thyme plants only contained B. cereus group consistently (above 10 3

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“…Plants release significant amounts of photosynthetically derived carbon (C) into the rhizosphere through root exudation, making root exudates a key factor in increasing microbial abundance and activity in the rhizosphere compared with bulk soil (Lynch, 1990; Kapoor & Mukerji, 2006). Low‐molecular‐weight C compounds present in root exudates, including sugars, organic acids (OAs) and amino acids, are readily assimilated by microorganisms and are proposed to play a primary role in regulating microbial community dynamics in the rhizosphere (Bais et al ., 2006; Weisskopf et al ., 2008).…”

Section: Introductionmentioning

confidence: 99%

Effects of selected root exudate components on soil bacterial communities

Shi

Richardson

O’Callaghan

et al. 2011

FEMS Microbiology Ecology

352

181

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Low-molecular-weight organic compounds in root exudates play a key role in plant-microorganism interactions by influencing the structure and function of soil microbial communities. Model exudate solutions, based on organic acids (OAs) (quinic, lactic, maleic acids) and sugars (glucose, sucrose, fructose), previously identified in the rhizosphere of Pinus radiata, were applied to soil microcosms. Root exudate compound solutions stimulated soil dehydrogenase activity and the addition of OAs increased soil pH. The structure of active bacterial communities, based on reverse-transcribed 16S rRNA gene PCR, was assessed by denaturing gradient gel electrophoresis and PhyloChip microarrays. Bacterial taxon richness was greater in all treatments than that in control soil, with a wide range of taxa (88-1043) responding positively to exudate solutions and fewer (<24) responding negatively. OAs caused significantly greater increases than sugars in the detectable richness of the soil bacterial community and larger shifts of dominant taxa. The greater response of bacteria to OAs may be due to the higher amounts of added carbon, solubilization of soil organic matter or shifts in soil pH. Our results indicate that OAs play a significant role in shaping soil bacterial communities and this may therefore have a significant impact on plant growth.

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Rhizosphere Microbial Community Dynamics

Cited by 10 publications

References 54 publications

Comparative Metaproteomic Analysis on Consecutively Rehmannia glutinosa-Monocultured Rhizosphere Soil

Comparative Metaproteomic Analysis on Consecutively Rehmannia glutinosa-Monocultured Rhizosphere Soil

Dynamics of culturable mesophilic bacterial communities of three fresh herbs and their production environment

Effects of selected root exudate components on soil bacterial communities

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