Dr Paul Dennis

Lecturer in Soil Science

School of Agriculture and Food Sciences
Faculty of Science
p.dennis@uq.edu.au
+61 7 334 69534

Overview

Paul Dennis leads an exciting research group that applies cutting-edge technologies to understand the roles of microorganisms and their responses to environmental change.

He is also a passionate educator and public speaker who advocates for the importance of biological diversity and evidence-based environmental awareness. He has talked about his research on ABC Radio and a range of other media outlets.

His teaching covers aspects of ecology, microbiology, plant and soil science, and climatology. He considers these topics to be of fundamental importance for the development of more sustainable societies and takes pride in helping others to obtain the knowledge and skills they need to build a better future.

Paul's research has taken him to Antarctica, the Amazon Rainforest, high mountains and oceans. The approaches used in his lab draw on a wide range of expertise in molecular biology, ecology, statistics, computer science, advanced imaging and soil science. He applies these skills to a wide-range of topics and systems including tropical agriculture, plant-microbe interactions, Antarctic marine and terrestrial ecology, biogeography, pollution and human health.

Qualifications

  • Doctor of Philosophy, University of London
  • BSc in Environmental Science (Hons), University of Wales

Publications

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Grants

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Supervision

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Available Projects

  • Soil microorganisms play critical roles in the functioning of terrestrial ecosystems. In this project, we will characterise the diversity of soil bacteria, archaea, fungi and other microeukarya along a pH gradient from Rothamsted, UK. Soil pH strongly influences microbial diversity. The relationship between diversity and other attributes of community structure, however, are poorly understood. In this project we will investigate the effect of species loss on community structure. This work has ramifications for conservation of terrestrial biodiversity.

  • Plants release up to 50% of photosynthetically derived carbon from their roots as a complex mixture of organic compounds known as root exudates. These compounds fuel diverse root-associated microbial communities that consist of plant growth-promoting species as well as those that cause disease or compete with plants for resources. By changing the mixture of exudates released from their roots, plants are thought to exert some level of control over the selection of their microbial symbionts.

    Current evidence indicates that most root-associated microorganisms are chemotactic, i.e. they have the ability to sense substrates released by roots and direct movement towards them. This ability enables them to respond rapidly to resources as they become available and out-compete neighboring populations. At present there is no information regarding the selectivity of different exudate components for specific groups of chemotactic organisms. Here, we will use a novel chemotaxis assay in combination with high-throughput sequencing and flow cytometry to identify and enumerate microorganisms that respond to different root exudate components. This information will identify exudates that are strongly associated with the recruitment of beneficial and/or deleterious organisms and should facilitate the development of crops that select for beneficial root-microbial communities.

  • When plants first emerged, it was into a world already colonised by microorganisms. Plant-microbe interactions influence the reproductive success of both partners and so plants have literally co-evolved with microbes for millions of years. For this reason, the plant together with its microorganisms (i.e. the holobiont) is being viewed as an appropriate unit of evolutionary selection. Mutalistic (win-win) interactions are likely to prosper within a holobiont as these enhance holobiont fitness. In the context of plants, it is likely that when stressed they release signals that attract microbes able to alleviate stress (e.g. mobilise nutrients or defend against attack). These mechanisms are likely to be encoded in plant genomes but have become weakened by crop breeding and applications of agrochemicals. For example, plant breeders typically focus on attributes like height or grain size and have not considered microbial diversity as a trait. Likewise, if plants are supplied fertiliser or pesticide, their reliance on microbes to enhance nutrition or fight disease is diminished.

    In this project we will use high-throughput sequencing to characterise the microorganisms associated with wheat, sorghum and their wild relatives. This will reveal genes associated with recruitment of the root microbiome that can be used to develop more sustainable farming systems. The project will involve input from Dr Paul Dennis (microbiomes), Dr Lee Hickey (wheat) and Prof Ian Godwin (sorghum).

View all Available Projects

Publications

Book Chapter

Journal Article

Conference Publication

Other Outputs

Grants (Administered at UQ)

PhD and MPhil Supervision

Current Supervision

  • Doctor Philosophy — Principal Advisor

    Other advisors:

  • Doctor Philosophy — Principal Advisor

    Other advisors:

  • Doctor Philosophy — Associate Advisor

  • Doctor Philosophy — Associate Advisor

  • Doctor Philosophy — Associate Advisor

  • Doctor Philosophy — Associate Advisor

Possible Research Projects

Note for students: The possible research projects listed on this page may not be comprehensive or up to date. Always feel free to contact the staff for more information, and also with your own research ideas.

  • Soil microorganisms play critical roles in the functioning of terrestrial ecosystems. In this project, we will characterise the diversity of soil bacteria, archaea, fungi and other microeukarya along a pH gradient from Rothamsted, UK. Soil pH strongly influences microbial diversity. The relationship between diversity and other attributes of community structure, however, are poorly understood. In this project we will investigate the effect of species loss on community structure. This work has ramifications for conservation of terrestrial biodiversity.

  • Plants release up to 50% of photosynthetically derived carbon from their roots as a complex mixture of organic compounds known as root exudates. These compounds fuel diverse root-associated microbial communities that consist of plant growth-promoting species as well as those that cause disease or compete with plants for resources. By changing the mixture of exudates released from their roots, plants are thought to exert some level of control over the selection of their microbial symbionts.

    Current evidence indicates that most root-associated microorganisms are chemotactic, i.e. they have the ability to sense substrates released by roots and direct movement towards them. This ability enables them to respond rapidly to resources as they become available and out-compete neighboring populations. At present there is no information regarding the selectivity of different exudate components for specific groups of chemotactic organisms. Here, we will use a novel chemotaxis assay in combination with high-throughput sequencing and flow cytometry to identify and enumerate microorganisms that respond to different root exudate components. This information will identify exudates that are strongly associated with the recruitment of beneficial and/or deleterious organisms and should facilitate the development of crops that select for beneficial root-microbial communities.

  • When plants first emerged, it was into a world already colonised by microorganisms. Plant-microbe interactions influence the reproductive success of both partners and so plants have literally co-evolved with microbes for millions of years. For this reason, the plant together with its microorganisms (i.e. the holobiont) is being viewed as an appropriate unit of evolutionary selection. Mutalistic (win-win) interactions are likely to prosper within a holobiont as these enhance holobiont fitness. In the context of plants, it is likely that when stressed they release signals that attract microbes able to alleviate stress (e.g. mobilise nutrients or defend against attack). These mechanisms are likely to be encoded in plant genomes but have become weakened by crop breeding and applications of agrochemicals. For example, plant breeders typically focus on attributes like height or grain size and have not considered microbial diversity as a trait. Likewise, if plants are supplied fertiliser or pesticide, their reliance on microbes to enhance nutrition or fight disease is diminished.

    In this project we will use high-throughput sequencing to characterise the microorganisms associated with wheat, sorghum and their wild relatives. This will reveal genes associated with recruitment of the root microbiome that can be used to develop more sustainable farming systems. The project will involve input from Dr Paul Dennis (microbiomes), Dr Lee Hickey (wheat) and Prof Ian Godwin (sorghum).

  • Nanotechnological materials are used extensively in a wide-range of consumer products and exhibit strong antimicrobial properties. Their use has increased dramatically in recent years along with their inevitable release into natural and managed ecosystems. Surprisingly, the environmental fate and behaviour of nano-materials is poorly understood despite evidence that they may suppress microbially driven ecosystem services such as nutrient cycling. In this project we will characterise the influence of nano-materials on the diversity of microorganisms that underpin the functioning of Earth’s terrestrial ecosystems. This work will help to determine the environmental impacts of nano-materials and facilitate the development of regulation to protect future environmental and human health.

  • Plants exude a complex mixture of organic compounds from their roots, which alter the availability of plant nutrients and fuel diverse microbial communities that influence plant health and nutrition. Nutrient deficiencies affect large areas of agricultural land. Nutrient deficiencies are known to strongly influence root exudation but these effects are poorly understood. Changes in root exudation could reduce crop yields by negatively affecting plant nutrient uptake and plant-microbe interactions. For this reason, better understanding of the effects of nutrient deficiencies on root exudation is needed to predict future food security. In this project, plants will be grown under differ nutrient deficiencies and root exudates will be collected and analyses using advanced chromatography and mass spectrometry methods.

  • Nutrient deficiencies and drought are major agricultural constraints. Fertilisers and irrigation help to alleviate these issues, but rely on non-renewable resources and contribute to environmental degradation. By 2050 there will be nine billion people on Earth, which places food security at the top of society’s challenges for the 21st century1. Soils harbour a wide variety of microbial taxa that significantly enhance plant nutrient acquisition and drought tolerance. These organisms could be used to more sustainably maintain, or enhance, global food security. In this project, microbes will be isolated from the roots of stressed plants and then screened for attributes that promote plant fitness under drought and nutrient stress.

  • Soil microorganisms play critical roles in the functioning of terrestrial ecosystems. In this project, we will characterise the diversity of soil bacteria, archaea, fungi and other microeukarya along a 750 km moisture gradient in South Australia. The incidence of drought is predicted to increase with climate change so better understanding of how drought influences microbially mediated ecosystems processes is key to our ability to maintain food security in the future.

  • Banana’s are one of Queensland’s main agricultural products. Microorganisms influence the health and nutrition of banana’s but the identities of microbes that live in association with banana’s are largely unknown. In his project we will apply high throughput sequencing technologies to characterise the banana microbiome and its role in plant growth promotion and disease prevention.