Earth Sciences Division Staff: Stéphanie M. Bernard

Biographical Summary

I am a plant biologist with a particular interest in plant carbon and nitrogen metabolism, plant-microbe interactions and the use of molecular techniques to investigate the plant response to changing environmental conditions. Within Gary Andersen’s lab, I work mainly on a DOE funded project (See Current Research) also involving Prof. David Ackerly from the Integrative Biology Department at UC Berkeley. This project is a collaboration amongst scientists from multiple disciplines (plant molecular biology, biochemistry, physiology, microbiology and soil carbon and nitrogen cycling) and is a great opportunity for me to learn more about the plants’ environment and how it can affect their metabolism.  

Current Research

An annual grassland mesocosm exploration of scaling from genomes to ecosystem function

PIs: Mary Firestone, Adam Arkin, David Ackerly, Gary Andersen, Margaret Torn

This multidisciplinary project investigates the effect of climatic changes on plants and soil microorganisms from an annual grassland ecosystem typical of California. We aim to gain a mechanistic understanding of the coordinated response of these two major players of the ecosystem and scale their responses from gene to whole ecosystem function.

As part of this project, we have set up greenhouses experiments using mesocosms filled with natural soil collected at Hopland Field Station (CA). The mesocosms were seeded with seven plants species (grasses and forbs) found in abundance in many California annual grasslands. Our focal species, Avena barbata, was grown as a monoculture and in a mixed community. The environmental factors studied with these greenhouses experiments are: three rainfall patterns (increase and decrease of water availability), two soil types (collected from two different California grasslands) and two temperature levels (ambient and +3°C). We have just finished the third and last season for these experiments and are currently analysing the samples collected.

Within this project, I am interested in studying the response of the plant at the molecular level. Particularly, my studies have involved cloning genes important in plant carbon and nitrogen metabolism and studying their expression in both roots and leaves using real-time RT-PCR. In collaboration with the Joint Genome Institute, I am analyzing ESTs from Avena barbata and plan on designing a high-density microarray specific of this species.

Professional Experience

Post-doctoral fellow, Earth Sciences Division, Lawrence Berkeley National Laboratory.

September 2005- present

Project: An annual grassland mesocosm exploration of scaling from genomes to ecosystem function

• Investigation of the coordinated responses to climate change of plants and soil microorganisms from a California annual grassland ecosystem with the aim of linking the responses from gene to ecosystem
• Cloning of genes associated with plant carbon and nitrogen metabolism and analysis of transcript abundance using real-time RT-PCR in both the roots and leaves of plants grown under differing climatic conditions
• Analysis of four cDNA libraries of Avena barbata sequenced using Sanger and 454-pyrosequencing method in collaboration with the Joint Genome Institute 

Graduate Studies, Crop Performance and Improvement division, Rothamsted Research (UK) and School of Biological Sciences, Lancaster University.

March 2002- September 2005

Project: Developing wheat with enhanced nitrogen use efficiency towards sustainable system of production

• Manipulation of the expression of cytosolic glutamine synthetase (GS) in wheat using particle bombardment
• Characterization of the wheat GS genes transcript profile and identification of two cytosolic GS genes involved in nitrogen remobilisation in senescing wheat leaves
• Phylogenetic analyses of the GS sequences from plants of the Poaceae family lead to the identification of three phylogenetically and functionally distinct GS sub-families

Research assistant, Crop Performance and Improvement division, Rothamsted Research (UK). March 2001- February 2002

• Analysis of the transcripts of two antioxidant enzymes, ascorbate peroxidase and catalase, in drought-stressed wheat and Arabidopsis thaliana (wild type and the Vtc-1 mutant deficient in ascorbate). This works suggested a role for ascorbate as a signalling molecule in plants
• As part of an a EU funded project entitled ‘Senescence and Oxidative Stress’ I carried out some measurements of enzymes activity and metabolites involved in oxidative stress during the senescence of pea (Pisum sativum) nodules

Education

2002-2005

PhD Rothamsted Research and School of Biological Sciences, Lancaster University

Advisors: Dimah Z. Habash, Christine H. Foyer and Brian G. Forde

2000-2001

Maitrise (Master’s degree by instruction; with honours), Université de Nantes (France), Engineering School in Chemistry-Biology and Rothamsted Research.

1999-2000

Licence (Bachelor’s degree; with honours), Université de Nantes (France), Engineering School in Chemistry-Biology

Grants & Awards

2007

Divisional Program Development Grant: ‘Genomic Basis of Plant Response to Soil Heterogeneity’ ($20k)

2006

Prize for best presentation awarded at the Rank Prize symposium ‘Can We Improve the Utilisation of Nitrogen in Cereals?’

Professional Activities & Associations

Member of the American Society of Plant Biologists

Journal reviewer:  New Phytologist (2007, 2009)