Dr Roger Pearce
Guest Member of Staff

  • Email: r.s.pearce@ncl.ac.uk
  • Telephone: +44 (0) 191 222 6898
  • Address: 227
    School of Biology,
    Ridley Building,
    Newcastle University,
    Newcastle upon Tyne
    NE1 7RU

Research Interests

Adaptation of plants to environmental stresses especially cold and freezing but also drought and salt.
Includes molecular and genetic analysis of acclimation and adaptation, with the potential to explain stress physiology and identify key aspects of evolution of stress tolerance.
Also includes investigation of freezing and freezing-induced damage in plants.

Current Work

Stresses of drought, soil salinity, and cold and freezing affect plant performance substantially. We aim to understand adaptations to these stresses at the molecular level as a basis for crop improvement and ultimately to understand the future of plant distributions.

Project 1. Quantitative Trait Locus and Insertional Mutant Analysis of Adaptation of Arabidopsis to abiotic stresses.
Mohammad Vaezi-Khakiki, Helal U. Ahmed, Abobakir Elhaj and Roger S Pearce

Acclimation to freezing, drought and salt stresses involves many genes including a potentially extensive sets coding for transcription factors and other regulatory genes. Which are most important in the evolution of adaptation to stress? In the long term, QTL analysis provides an experimental means to investigate divergence within a species. In the short term, it provides data to find novel genes involved in acclimation. We used QTL analysis, in the Lister and Dean Arabidopsis mapping population, to identify a variety of loci, and we found co-located polymorphic genes by searching the Cereon/Monsanto database. Novel candidates are being identified by testing lines carrying insertional mutations in the corresponding genes.

Project 2. Acclimation of Epidermis to Freezing Stress.
Khalifa S Mohamed, M Shamsher Ali, Abobakir Elhaj and Roger S Pearce

Acclimation to stress is usually investigated in whole organs or whole shoots. However, different tissues differ in the genes they express during cold acclimation (Pearce et al, 1998, Plant Physiology 117: 787-795). This might explain some of the complexity characteristic of acclimation to stress. We use the peeled lower epidermis from Arabidopsis leaves to compare biochemical and molecular traits in the epidermis and whole leaf. Expression of stress-related genes including transcription factors differ and the role of this in acclimation is being investigated using insertional mutant lines.

Project 3. Regulation of Cold Acclimation by Sugars.
Abobakir Elhaj, Iona Rekarte-Cowie, Omar S Ebshish and Roger S Pearce

Sugar supply regulates gene expression and freezing tolerance in cell cultures in a way normally induced by cold in the whole plant (Tabaei Aghdaei et al, 2003. Journal of Experimental Botany 54: 1565-1575). To understand the relative regulatory roles of sugars and cold, we investigated the effects of sucrose supply on acclimation of Arabidopsis leaves. Testing GUS reporter expression driven by the COR78 promoter, we found that sucrose supply regulated expression and, as expected, cold was also necessary. Current work is focussed on characterising the role of sugars further and understanding the underlying mechanism.

Esteem Indicators

- Internationally used referee for grant applications (including USDA and European grant-awarding bodies) and journal manuscripts (including the high-scoring journal Plant Physiology).
- Member of CryoLetters editorial board from January 2008.

Undergraduate Teaching

Contributions at all levels. Largest contributions are:

Social Impacts of Biology/Biotechnology
BIO3015/8011 (BSc Honours year and taught masters programmes)

Modern Biology has thrown up issues that concern ordinary people, such as genetically modified foods and xenotransplantation. To decide whether or not such technologies present risks one needs facts, but even with facts the issues remain, since people may agree on the facts but still disagree as to whether or not we should use these technologies. The purpose of this module is to show how the non-scientific issues that are raised can be considered and how one could try to resolve them, and therefore presents example issues and gives students guidance and practice in organising their thinking and in presenting arguments about what should be done.

Cell Proliferation and Death (BIO3013; BSc Honours year)

The survival of organisms depends on cellular survival of environmental extremes, and on the genetic control of cell multiplication and cell death. To understand these challenges one must understand the effects of physical and chemical factors – desiccation, extreme temperature, free-radical attack – on macromolecular stability; and on the other hand one must understand the role of genetic mutation in the balance between cell survival and programmed cell death. These issues are brought together in one module to underpin understanding of the complexity of life, to illustrate the modern methodologies that can be used in understanding this complexity, and to demonstrate the common biological principles that underlie these challenges to survival to all forms of organisms.