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@PHDTHESIS{Erdrich:1029764,
author = {Erdrich, Sebastian},
title = {{U}nderstanding the dynamic of
{P}lant-{B}acteria-{B}acteriophage interactions as a means
to improve plant performance},
volume = {287},
school = {Düsseldorf},
type = {Dissertation},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {FZJ-2024-05219},
isbn = {978-3-95806-791-2},
series = {Reihe Schlüsseltechnologien / Key Technologies},
pages = {ix, 176},
year = {2024},
note = {Dissertation, Düsseldorf, 2024},
abstract = {Plant protection is crucial in the context of a secure food
supply. With antibiotic-resistant bacteria on the rise, we
explore new, sustainable plant protection strategies and
utilise naturally occurring bacterial viruses to counter
pathogenic bacteria. These viruses, known as bacteriophages,
are highly specific and outnumber bacteria by a factor of
ten, and are present in every habitat on Earth. Despite
their abundance, the number of available isolates for plant
pathogenic bacteria is still very limited. The bacterial
genus of Xanthomonas contains many well-known plant
pathogens with the ability to infect some of the most
important crop plants, causing significant economic damage.
Unfortunately, classical pest control strategies are neither
particularly efficient nor sustainable. Investigating
phage-based strategies, we set the foundation in our lab by
isolating seven novel Xanthomonas phages (Langgrundblatt1,
Langgrundblatt2, Pfeifenkraut, Laurilin, Elanor, Mallos, and
Seregon). As part of this PhD project, we further
characterised, classified and tested them for their
biocontrol potential in vitro. Besides good prerequisites
for subsequent in planta experiments, we established four
taxonomic novel genera. With seeds being one of the major
transmission routes for bacterial pathogens in agriculture,
we tested strategies to protect plants from the early
stages. Therefore, phages for two important crop pathogens,
Pseudomonas syringae and Agrobacterium fabrum (tumefaciens),
were isolated and tested for their interaction with the seed
coat mucilage, deepening the understanding of seed-based
biocontrol. Some of the tested phages were highly dependent
on mucilage for seed binding, whereas podophage Athelas
showed the highest dependency. The significance of this
observation was broadened by testing further podoviruses of
the Autographiviridae family obtained from the systematic E.
coli (BASEL) phage collection. These showed a similar
dependence on the mucilage for seed adhesion. Phage coating
effectively increased the survival rate of plant seedlings
in the presence of the pathogen. Long-term activity tests
revealed a high stability of phages on seed surfaces. The
utilisation of non-virulent host strains was further
successfully applied to enrich the presence of infectious
phage particles on seed surfaces. Altogether, our study
highlights the potential of phage-based applications as
sustainable biocontrol strategy at the seed level. A further
part of this work aimed at gaining a molecular understanding
of the tripartite interaction between plants, bacteria, and
phages in a novel tripartite transcriptomics approach. We
aimed to fill the knowledge gap on how the plants gene
expression is responding during phage-based biocontrol. For
this purpose, a gnotobiotic system was used to study
infection of Arabidopsis thaliana with the plant pathogen
Xanthomonas campestris. Here, the application of the
Xanthomonas phage Seregon could successfully counteract the
bacterial infection almost to the level of the uninfected
control. Additionally, we observed a significant variation
in the expression of defence-related genes throughout the
tripartite interaction. While X. campestris inoculation led
to expression of several salicylic acid responsive genes
like WRKY70 and WAK1, the treatment of X. campestris with
phage Seregon led to a significantly reduced upregulation of
these genes. We also identified GRP3.1 as uniquely
upregulated in response to phage-based control of X.
campestris. In summary, this thesis offers unprecedented
insights into the molecular-level tripartite interactions
between plants, bacteria, and phages, thereby establishing a
crucial foundation for the development of sustainable
biocontrol strategies in agriculture utilizing phages.},
cin = {IBG-1 / IBG-2},
cid = {I:(DE-Juel1)IBG-1-20101118 / I:(DE-Juel1)IBG-2-20101118},
pnm = {2171 - Biological and environmental resources for
sustainable use (POF4-217)},
pid = {G:(DE-HGF)POF4-2171},
typ = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
urn = {urn:nbn:de:0001-2501281112485.44321598019},
doi = {10.34734/FZJ-2024-05219},
url = {https://juser.fz-juelich.de/record/1029764},
}