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Dynamics of root microorganisms in closed hydroponic cropping systems

Rosberg, Anna Karin (2014). Dynamics of root microorganisms in closed hydroponic cropping systems. Diss. (sammanfattning/summary) Alnarp : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2014:51
ISBN 978-91-576-8050-1
eISBN 978-91-576-8051-8
[Doctoral thesis]

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Greenhouse production of vegetables in closed hydroponic cropping systems is a resource-efficient technique for the production of high-quality produce with a high yield per unit area. While this type of cropping system allows savings in terms of water and nutrient use, the recirculation of water increases the risk of pathogen dispersal. Oomycetous pathogens in particular, such as Pythium, thrive in aquatic environments and are among the most destructive pathogens. Root pathogen outbreaks could be controlled by sustaining a stable and high level of general microbiota. It is therefore of utmost importance to understand how biotic and abiotic factors affect the indigenous root-associated microbiota.

In the present thesis, the impact of pathogen inoculation, plant age, nutrient availability and use of plant protection products on microbial communities associated with root and nutrient solution was investigated. It was demonstrated that all these factors had an effect on the indigenous microorganisms. Plant age in particular was a significant driver of microbial community structure due to its significant impact on root exudation patterns. Using 454-pyrosequencing, the effect on bacterial communities of the inoculation of P. ultimum was visualized. Although the effect was strongest at the fruit-bearing plant stage, clear differences were seen also in the seedling and flowering stages. Nutrient availability was revealed to have an impact on the number of colony-forming units of bacteria, fungi and fluorescent pseudomonads. Organic carbon specifically was shown to be the main driving force of microbial growth. However, not only the quantity, but also the quality and ratios between the different organic and inorganic nutrients had an effect on microbial numbers. Through DGGE analysis, a shift in the bacterial community structure was seen after the addition of a fungicide in the nutrient solution. The microorganisms present in the nutrient solution were not able to degrade the fungicide.

This thesis also demonstrates the importance of combining culture-dependent and culture-independent methods in the analysis of microbial communities.

Authors/Creators:Rosberg, Anna Karin
Title:Dynamics of root microorganisms in closed hydroponic cropping systems
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2014
Number of Pages:62
I.Rosberg, A.K., Gruyer, N., Hultberg, M., Wohanka, W. & Alsanius, B.W. (2014). Monitoring rhizosphere microbial communities in healthy and Pythium ultimum inoculated tomato plants in soilless growing systems. Scientia Horticulturae 173, 106-113.
II.Rosberg, A.K., Wohanka, W., Hultberg, M. & Alsanius B.W. (2014). Impacts of Pythium ultimum inoculation on tomato root-associated bacterial communities, as examined by 454 pyrosequencing (submitted).
III.Rosberg, A.K., Wohanka, W., Hultberg, M. & Alsanius B.W. (2014). Organic carbon and micronutrients have an effect on microbial dynamics in nutrient solutions of diseased and non-diseased hydroponic systems (manuscript).
IV.Rosberg, A.K., Wohanka, W., Hultberg, M. & Alsanius B.W. (2014). Organic carbon and micronutrients have an effect on microbial dynamics in nutrient solutions of diseased and non-diseased hydroponic systems (manuscript).
V.Alsanius, B.W., Rosberg, A.K., Hultberg, M., Khalil, S. & Jung, V. (2014). Understanding and utilizing naturally-occurring microbes against plant pathogens in irrigation reservoirs. In: Hong, C. et al. Biology, Detection, and Management of Plant Pathogens in Irrigation Water. Chapter 28; 347-364. APS (in press).
Place of Publication:Alnarp
Publisher:Dept. of Biosystems and Technology, Swedish University of Agricultural Sciences
Associated Programs and Other Stakeholders:Z - SLU - Library > Odla mera
ISBN for printed version:978-91-576-8050-1
ISBN for electronic version:978-91-576-8051-8
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:F Plant production > F01 Crop husbandry
H Protection of plants and stored products > H20 Plant diseases
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Microbiology (Microbiology in the medical area to be 30109)
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Horticulture
Agrovoc terms:cropping systems, hydroponics, nutrient solutions, greenhouse crops, lycopersicon esculentum, tomatoes, rhizosphere, roots, pathogens, bacteria, fungi, pythium, age, carbon, nutrient availability, monitoring
Keywords:bacteria, fungi, microbial communities, nutrient solution, organic carbon, plant age, Pythium ultimum, rhizosphere, root pathogens, tomato
Permanent URL:
ID Code:11393
Faculty:LTV - Fakulteten för landskapsarkitektur, trädgårds- och växtproduktionsvetenskap
Department:(LTJ, LTV) > Department of Biosystems and Technology (from 130101)
External funders:FORMAS
Deposited By: Anna Karin Rosberg
Deposited On:05 Aug 2014 12:32
Metadata Last Modified:21 Oct 2015 14:01

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