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Endophytic fungi in elms

implications for the integrated management of Dutch elm disease

Blumenstein, Kathrin (2015). Endophytic fungi in elms. Diss. (sammanfattning/summary) Alnarp : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2015:106
ISBN 978-91-576-8410-3
eISBN 978-91-576-8411-0
[Doctoral thesis]

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Integrated pest management calls for new biocontrol solutions in management of forest diseases. Endophytic fungi that are commonly found in tree tissue may have potential in biocontrol. However, the links between endophyte status and disease tolerance are still unclear, and we know little about the mechanisms by which the endophytes can influence tree pathogens.

The first goal of the thesis was to compare the endophyte status in elm (Ulmus spp.) trees with low vs. high susceptibility to Dutch elm disease (DED), caused by Ophiostoma fungi, and to find correlations between endophytes and the susceptibility pattern of the trees. The second goal was to investigate the potential mechanisms of antagonism by the endophytes towards the pathogen. Thus, endophytes were isolated from leaves, bark and xylem of elms that differed in DED susceptibility. The isolates were screened for their potential to counteract the pathogen in dual cultures. Selected strains were investigated using Phenotype MicroArrays to obtain the substrate utilization profiles that reflect the endophytes’ ability to compete with the pathogen for a nutritional niche. To test for a protective effect against the disease, promising isolates were injected into young elms. Preliminary analyses were done to identify the extracellular chemicals that some of the endophytes released into the growth medium.

The results showed that the frequency and diversity of endophytes was higher in xylem of elms with high susceptibility to DED. Some endophytes deadlocked the pathogen with extracellular chemicals in vitro, while others had a faster growth rate. Several endophytes were able to utilize substrates more effectively than the pathogen. A preventive treatment with endophytes protected elms against DED, but the effect was unstable across years. Bioactive fungal extracts had a complex chemical profile, and the individual compounds in the extracts remain to be identified. Because endophytes antagonized the pathogen through different mechanisms, I suggest that an endophyte-based biocontrol of DED could be best achieved through a synergistic effect of several endophyte strains.

Authors/Creators:Blumenstein, Kathrin
Title:Endophytic fungi in elms
Subtitle:implications for the integrated management of Dutch elm disease
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :26 November 2015
Depositing date:26 November 2015
Number of Pages:84
IMartín, J.A., Witzell, J., Blumenstein, K., Rozpedowska, E., Helander, M., Sieber, T.N. & Gil, L. (2013). Resistance to Dutch Elm Disease reduces presence of xylem endophytic fungi in elms (Ulmus spp.). Plos One, 8(2).
IIMartín, J.A., Macaya-Sanz, D., Witzell, J., Blumenstein, K. & Gil, L. (2015). Strong in vitro antagonism by elm xylem endophytes is not accompanied by temporally stable in planta protection against a vascular pathogen under field conditions. Eur J Plant Pathol, 142(1), pp. 185-196.
IIIBlumenstein, K., Macaya-Sanz, D., Martín, J.A., Albrectsen, B.R. & Witzell, J. (2015). Phenotype MicroArrays as a complementary tool to next generation sequencing for characterization of tree endophytes. Front Microbiol, 6.
IVBlumenstein, K., Albrectsen, B.R., Martín, J.A., Hultberg, M., Sieber, T.N., Helander, M. & Witzell, J. (2015). Nutritional niche overlap potentiates the use of endophytes in biocontrol of a tree disease. Biocontrol.
Place of Publication:Alnarp
Publisher:Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-8410-3
ISBN for electronic version:978-91-576-8411-0
Additional Information:The project was funded by FONASO, an Erasmus Mundus Joint Doctoral Degree Programme (granted by the European Commission).
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:H Protection of plants and stored products > H20 Plant diseases
K Forestry > K70 Forest injuries and protection
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 > Forest Science
Agrovoc terms:ulmus, forest trees, fungal diseases, endophytes, fungi, ophiostoma, disease resistance, defence mechanisms, biological control, integrated pest management
Keywords:Biocontrol, Phenotype MicroArray, Nutrient utilization, Fungus-fungus interactions, Antagonism, Niche differentiation, Ophiostoma spp., Ulmus spp.
Permanent URL:
ID Code:12862
Faculty:S - Faculty of Forest Sciences
Department:(S) > Southern Swedish Forest Research Centre
External funders:European Commission
Deposited By: Kathrin Blumenstein
Deposited On:27 Nov 2015 09:14
Metadata Last Modified:10 Sep 2020 13:41

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