Manipulating the soil microbiome for improved plant response to nitrogenand drought stress

The frequency of extreme weather events such as
drought is predicted to increase (IPPC, 2014) and yet crops in Australia and
the UK are already being adversely affected. Drought not only causes
water limitation, but also changes the cycling and availability of essential
nutrients (especially N) in the soil (e.g. Jackson et al., 2008). In response,
plants alter their root system architecture (Lynch, 2007), however, root
traits for maximizing water uptake (e.g. deep roots) can be poorly adapted
to acquiring nutrients and limited by sub-soil strength. In addition the root
system of cereals, such as wheat, is comprised of root types which are
genetically distinct (Hochholdinger et al., 2004) and yet the functional
importance for nutrient and water uptake of each type remains unknown.
It is increasingly recognized that the interactions between roots and the
soil microbiome heavily impact on plant growth through shaping the
structure of the soil surrounding roots, controlling root-soil contact,
releasing nutrients from organic matter and regulating important
mechanisms like water and nutrient uptake efficiency (Daly et al., 2015).
Building on joint and complementary expertise of both partners in soil
ecology, soil biophysics, root science and modelling, we will explore the
link between soil microbial communities, nutrient cycling and crop drought
and nutrient resilience in wheat (a major crop for both countries) across a
range of UK & Australian soil types.
Aims & Objectives: 1 – To determine the dynamic physiological responses
leading to drought and nutrient stress tolerance in wheat varieties.
Comparing nutrient and drought tolerant wheat varieties to non-tolerant
varieties the student will investigate dynamic processes including nutrient
and water uptake by different root classes (e.g. using labelled uptake
studies) and root growth rates and responsiveness to replete and deficient
nutrient/water conditions (quantified using X-ray μCT).
2 – To investigate how soil nutrient cycling and the soil microbiome
influence the tolerance of selected wheat varieties to the combination of
nutrient deficiency and drought stress. A range of traditional and cutting
edge genomic techniques will be used to measure nutrient cycling
processes and microbial community dynamics in the soil surrounding roots
of tolerant and intolerant wheat varieties. This will be related to how
plants respond to drought and nutrient stress.
Facilities & Training: The student will receive training in several areas
including imaging and modelling (recognized as vital skills for biosciences
by research councils) utilizing the new state of the art Hounsfield μCT
Facility (UoN) to image microscopic 3-D root-soil dynamics through space
and time. This will be coupled with studies of soil nutrient cycling,
genomics and plant nutrient and water uptake (UoA), under a range of
future climate and nutrient availability scenarios.
Student Mobility: We anticipate a truly joint research project with the
student spending an equal length of study with each partner. The initial 12
months will be at UoA, screening wheat varieties under drought and
nutrient deficiency and undertaking nutrient uptake studies. The next 24
months will be based at UoN, μCT imaging the tolerant and intolerant lines
for developmental dynamics of the root systems in combinations with soil
microbes (e.g. mycorrhizae) selected at UoA. The final 12 months will be
spent at UoA investigating the role of soil nutrient cycling and the soil
microbiome, and writing up. Either institute could act as primary host,
however we propose UoA as the student will start there.