Download Assessing soil and rhizosphere microbiomes of native

2017_56: Assessing soil and rhizosphere
microbiomes of native and invasive plants on South
Georgia Island
Supervisors: Dr Anne D. Jungblut ([email protected]), Dr Thomas Bell (Life
Sciences); Baruch Spiro, (Natural History Museum)
Department: Natural History Museum / Life Sciences
Microorganisms are a major component of soils, and are essential for maintaining key
terrestrial ecosystems, where they form diverse assemblages of bacteria, archaea,
fungi and other microbial eukaryotes. Plants interact with microbes, which can effect
plant growth, health, and adaptation to stressful environments. The rhizosphere
comprises microorganism and soils that are directly in contact with plant roots. It is a
selective environment with microbial communities varying between plant species likely
due to excretion of compounds including antimicrobials and organic acids. Due to the
close interaction between microorganisms and plants, the microbial diversity and
activity of the rhizosphere is a key component for plant fitness and changes in plantmicrobe interactions may have implications for plant growth.
Plant invasions are a global concern because they pose a direct threat to biodiversity
and natural resource management, in particular in protected and remote areas. This
is especially the case for the South Atlantic island, South Georgia, which is located in
the polar transition zone (northern limit of winter sea ice and the southern fringe of the
Polar Front Zone) and currently experiencing rapid climatic change. Long term
monitoring and an invasive plant eradication program has provided an understanding
of the abundance, distribution and management of some of the invasive plant
populations on South Georgia, but little is still known about the underlining
mechanisms of plant-microbe interactions and influence of invasive plants on the soil
and rhizosphere microbiomes in a colder climate such as South Georgia island.
The aims of the project are 1) to assess and compare bacteria, archaea and microbial
eukaryote composition bulk soil and rhizosphere of native and invasive plants on
South Georgia Island; 2) to characterize physical and chemical properties of soils; and
3) to evaluate how rhizosphere microbiomes and growth of native plants may be
affected by invasive species.
For more information on how to apply visit us at www.imperial.ac.uk/changingplanet
Science and Solutions for a Changing Planet
The PhD student will carry out field work to collect rhizosphere and bulk soil samples
on South Georgia for molecular and chemical analysis. Microbial community
assemblage (bacteria, archaea, fungi and microbial eukaryotes) will be analyzed using
a combination of environmental DNA and high throughput sequencing, bioinformatics,
statistical and microbial community structure analysis techniques. The chemistry of
the soils will be determined using isotope and trace elements analysis. This will enable
us to determine what nutrients are available and how much, which are limited and
where the dominant sources are. Field-based transplant manipulation experiments will
be performed in combination with DNA sequencing, soil chemistry and carbon
measurements to evaluate how rhizosphere microbiomes and growth of native plants
may be affected by invasive species.
For more information on how to apply visit us at www.imperial.ac.uk/changingplanet