Tim is a plant physiologist/soil scientist and has worked on the dynamics of nutrients in the rhizosphere of plants and variation in root traits for the last 24 years.
Understanding how plants react to and alter their external environment is key to optimising their nutrition and therefore the sustainability of agriculture and natural ecosystems. He is specifically interested in understanding the physiology of and genetic controls on plant responses to P-deficiency and drought. He has specific expertise in understanding how the external environment mitigates plant physiological and genetic responses to a lack of phosphorus in the rhizosphere. In addition, he is interested in how plants interact with the soil chemical, biological and physical environment to impact nutrient cycles. His recent research includes work on the ability of Bere barley to cope with extreme micronutrient deficiency, the role of root exuded enzymes and mycorrhizae in making organic P available and the impact of root hairs on the ability of barley to acquire soil resources.
The direction of his research is moving towards investigating the use of barley diversity for climate change mitigation and adaptation. The aim is to discover genes and traits to both optimize rhizosphere N and P cycles, promote C sequestration to soils and help adapt crops to abiotic stress associated with climate change. Understanding the rhizosphere processes involved in the N, P and C cycle and how these are affected by genotypic variation in root exudate composition will be key to managing both fertilizer use efficiency and in reducing greenhouse gas emissions from agriculture.
My personal research and that of the group which I manage, has produced a number of research highlights in the last 5 years:
Exudation of phytase and citrate by plants:Demonstration that plants exuding phytase and citrate change rhizosphere biochemistry to the plants benefit and that interactions between plants with different traits is important. We are currently developing 2D techniques for assessing organic P dynamics in-situ and in the future will apply knowledge into designing tools which allow better management of the rhizosphere.
Root hairs and rhizosheaths: Demonstration that root hairs are critical to the ability of cereals to yield under P-deficient conditions and that their absence is not compensated by mycorrhizae. In addition, the presence of root hairs is implicit in the development of rhizosheaths. We know that the rhizosheath trait is highly heritable, making it a good target for breeding of improved cultivars of cereal crops for future agricultural environments. In the future we aim to identify the genetic control and evolutionary origin of this trait and understand the physiology of how root hairs generate rhizopsheres.
Using traditional landraces for sustainability: Demonstration that extant barley landraces selected over many generations on marginal soils have adapted to tolerate limited micronutrient availability. We show that Bere barley has unprecedented abilities to tolerate Mn deficiency and constitutes a valuable resource of untapped adaptive genetic variation. In the future we will use genetics approaches to identify useful cultivars and genes controlling the key adaptive traits to underpin crop improvement in marginal soils
In the last five years I have supervised 8 Ph.D. students and have hosted visiting scientists from China, Australia, Turkey and Denmark. I am section editor for Plant and Soil and have examined 10 PhD theses in five different countries. Also in the last 5 years, the group has attracted over £5m in grants to fund our research and have produced over 50 peer reviewed journal articles and book chapters.
Links:
[1] https://orcid.org/0000-0003-3231-2159