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QUADRAT DTP CASE: The wild grass Holcus lanatus as a model organism to study plant genetics/rhizosphere microbe/soil management interaction effects


   School of Biological Sciences

  , ,  Wednesday, December 01, 2021  Competition Funded PhD Project (Students Worldwide)

Belfast United Kingdom Agricultural Sciences Bioinformatics Ecotoxicology Environmental Chemistry Genetics Microbiology Molecular Biology Soil Science

About the Project

The project aims to investigate plant-soil interactions in response to long-term nutrient fertilization either in organic or inorganic forms. The project will use a 51-year old experiment established at Hillsborough in 1970 and managed by AFBI (https://www.ecologicalcontinuitytrust.org/hillsborough-lts). The research will focus on high and low P adapted Holcus lanatus (L) and associated rhizosphere fungi, bacteria and archaea. The long-term slurry (LTS) experiment managed by the Agri-Food & Biosciences Institute (AFBI) offers an excellent research platform to better understand edaphic stress and the response of plant specific rhizosphere microbial communities. This grassland experiment has been treated with cattle slurry, pig slurry, NPK fertiliser, and an untreated control. Previous surveys of plants in each plot have already established that Holcus lanatus (L) is highly abundant in all control plots and present at various levels of abundance in all treatment plots. H. lanatus is a wild grass that is able to grow in marginal soils and is also an invasive plant species in grass pastures. Hence H. lanatus is relevant to research concerned with soil restoration, wild grassland and pastures management in the UK. Crucially, H. lanatus shows a widespread polymorphism with respect to tolerance to arsenic that is linked to differences in phosphorous use efficiency, with ~50% of the population adapted to low and 50% to higher levels of availability of P (Meharg et al., 1994, Meharg et al., 2014). It has been hypothesised that this polymorphism has pleotropic consequences on H. lanatus reproductive strategy: vegetative for low-P, sexual for high-P. This means that H. lanatus is also an excellent model to study the interaction of rhizosphere microbes and plant genetics within the context of soil management and P nutrition. For P rhizosphere bacteria and fungi are thought to have an essential role in mineralization from SOM, and given that the LTS plots vary greatly in SOM and P status (Fonara et al., 2020a), yet have the same fundamental starting soil conditions. Thus these experimental plots offer an excellent experimental design to test hypotheses regarding plant-soil interactions in relation to differences in P availability. The age of the plots offers an intriguing possibility that there will be phenotypic selection in the plants according to P-stress, and potentially reflected in soil biodiversity. Investigation of the abundance of low and high P adapted H. lanatus in each plot alongside their rhizosphere microbial communities will provide novel insights into the interactions between the applied treatments and specific plant-microbiomes of high and low P adapted H. lanatus in each plot. The focus will be on the study of the rhizosphere microbiomes of high and low P adapted H. lanatus and impact on plant uptake of toxic metals/metalloids, phosphate and other plant nutrient elements under a range of different soil management treatments. Research outcomes will be relevant for optimisation of soil restoration, wild grassland and low-input pasture management.

More project details are available here:

https://www.quadrat.ac.uk/quadrat-projects/

How to apply:

https://www.quadrat.ac.uk/how-to-apply/ 


Funding Notes

QUADRAT studentships are open to UK and International candidates (EU and non-EU). Funding will cover UK tuition fees/stipend/research & training support grant only.
Before applying please check full funding and eligibility information: View Website

References

1. Meharg AA, Bailey J, Breadmore K, Macnair MR, 1994. Biomass allocation, phosphorous nutrition and vesicular-arbuscular mycorrhizal infection in clones of Yorkshire Fog, Holcus lanatus L. (Poaceae) that differ in their phosphate uptake kinetics and tolerance to arsenate. Plant Soil, 160:11–20.
2. Meharg C, Khan B, Norton G, Deacon C, Johnson D, Reinhardt R, et al, 2014. Trait-directed de novo population transcriptome dissects genetic regulation of a balanced polymorphism in phosphorus nutrition/arsenate tolerance in a wild grass, Holcus lanatus. New Phytol, 201:144–54.
3. Young E., Carey M., Meharg A.A. et al. 2018. Microbiome and ecotypic adaption of Holcus lanatus (L.) to extremes of its soil pH range, investigated through transcriptome sequencing. Microbiome 6, 48.
4. Christie P., Beattie J. A. M., 1989. “Grassland Soil Microbial Biomass and Accumulation of Potentially Toxic Metals from Long-Term Slurry Application.” Journal of Applied Ecology, 26(2): 597–612.
5. Christie P., Kilpatric D.J. 1992. Vesicular-arbuscular mycorrhiza infection in cut grassland following long-term slurry application. Soil Biology and Biochemistry, 24( 4):325-330
6. Fornara D.A., David Flynn D., Caruso T. 2020a. Improving phosphorus sustainability in intensively managed grasslands: The potential role of arbuscular mycorrhizal fungi. Science of The Total Environment, 706:135744
7. Fornara D.A., David Flynn D., Caruso T. 2020b. Effects of nutrient fertilization on root decomposition and carbon accumulation in intensively managed grassland soils. Ecosphere 11(4):2150-8925
8. JIA, Z., ZHOU X., XIA W., Fornara D.A., et al., 2020. Evidence for niche differentiation of nitrifying communities in grassland soils after 44 years of different field fertilization scenarios. Pedosphere, 30(1):87-97.

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